rebase from master

2024-09-24 18:50:49 +00:00 · 2019-11-07 08:38:55 +01:00 · 2019-11-07 08:38:55 +01:00 · 5994d551a6
commit 5994d551a6
parent 6986fe2ec1 31aff291e6
614 changed files with 16072 additions and 5062 deletions
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@ -1,3 +1,4 @@
 dbms/* @ClickHouse/core-assigner
+utils/* @ClickHouse/core-assigner
 docs/* @ClickHouse/docs
 docs/zh/* @ClickHouse/docs-zh
--- a/.github/PULL_REQUEST_TEMPLATE.md
+++ b/.github/PULL_REQUEST_TEMPLATE.md
@ -1,8 +1,6 @@
 I hereby agree to the terms of the CLA available at: https://yandex.ru/legal/cla/?lang=en

-For changelog. Remove if this is non-significant change.
-
-Category (leave one):
+Changelog category (leave one):
 - New Feature
 - Bug Fix
 - Improvement
@ -11,11 +9,14 @@ Category (leave one):
 - Build/Testing/Packaging Improvement
 - Documentation
 - Other
+- Non-significant (changelog entry is not needed)

-Short description (up to few sentences):
+
+Changelog entry (up to few sentences, not needed for non-significant PRs):

 ...

+
 Detailed description (optional):

 ...
--- a/.github/labeler.keywords.yml
+++ b/.github/labeler.keywords.yml
@ -1 +0,0 @@
-pr-feature: "New Feature"
--- a/.github/labeler.yml
+++ b/.github/labeler.yml
@ -1,19 +0,0 @@
-# Documentation PRs
-documentation:
-  - "**/*.md"
-  - "docs/**/*"
-pr-documentation:
-  - "**/*.md"
-  - "docs/**/*"
-
-# Component labels
-comp-mutations:
-  - "**/*Mutation*"
-comp-matview:
-  - "**/*MaterializedView*"
-comp-skipidx:
-  - "**/*Indices*"
-comp-kafka:
-  - "dbms/src/Storages/Kafka/**/*"
-  - "dbms/tests/integration/test_storage_kafka/**/*"
-  - "utils/kafka/**/*"
--- a/.github/stale.yml
+++ b/.github/stale.yml
@ -1,67 +0,0 @@
-# Configuration for probot-stale - https://github.com/probot/stale
-
-# Number of days of inactivity before an Issue or Pull Request becomes stale
-daysUntilStale: 45
-
-# Number of days of inactivity before an Issue or Pull Request with the stale label is closed.
-# Set to false to disable. If disabled, issues still need to be closed manually, but will remain marked as stale.
-daysUntilClose: 30
-
-# Only issues or pull requests with all of these labels are check if stale. Defaults to `[]` (disabled)
-onlyLabels: []
-
-# Issues or Pull Requests with these labels will never be considered stale. Set to `[]` to disable
-exemptLabels:
-  - bug
-  - feature
-  - memory
-  - performance
-  - prio-crit
-  - prio-major
-  - st-accepted
-  - st-in-progress
-  - st-waiting-for-fix
-
-# Set to true to ignore issues in a project (defaults to false)
-exemptProjects: false
-
-# Set to true to ignore issues in a milestone (defaults to false)
-exemptMilestones: false
-
-# Set to true to ignore issues with an assignee (defaults to false)
-exemptAssignees: false
-
-# Label to use when marking as stale
-staleLabel: stale
-
-# Comment to post when marking as stale. Set to `false` to disable
-markComment: >
-  This issue has been automatically marked as stale because it has not had
-  recent activity. It will be closed if no further activity occurs. Thank you
-  for your contributions.
-
-# Comment to post when removing the stale label.
-# unmarkComment: >
-#   Your comment here.
-
-# Comment to post when closing a stale Issue or Pull Request.
-# closeComment: >
-#   Your comment here.
-
-# Limit the number of actions per hour, from 1-30. Default is 30
-limitPerRun: 30
-
-# Limit to only `issues` or `pulls`
-# only: issues
-
-# Optionally, specify configuration settings that are specific to just 'issues' or 'pulls':
-pulls:
-  daysUntilStale: 365
-  markComment: >
-    This pull request has been automatically marked as stale because it has not had
-    any activity for over a year. It will be closed if no further activity occurs. Thank you
-    for your contributions.
-
-# issues:
-#   exemptLabels:
-#     - confirmed
--- a/.github/workflows/labeler.yml
+++ b/.github/workflows/labeler.yml
@ -1,11 +0,0 @@
-name: "Pull Request Labeler"
-on:
-  pull_request
-
-jobs:
-  by-filename:
-    runs-on: ubuntu-latest
-    steps:
-    - uses: "actions/labeler@v2"
-      with:
-        repo-token: "${{ secrets.GITHUB_TOKEN }}"
--- a/.gitignore
+++ b/.gitignore
@ -245,3 +245,6 @@ website/package-lock.json
 /.ccls-cache

 /compile_commands.json
+
+# Toolchains
+/cmake/toolchain/*
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@ -1,3 +1,294 @@
+## ClickHouse release v19.16.2.2, 2019-10-30
+
+### Backward Incompatible Change
+* Add missing arity validation for count/counIf.
+  [#7095](https://github.com/ClickHouse/ClickHouse/issues/7095)
+[#7298](https://github.com/ClickHouse/ClickHouse/pull/7298) ([Vdimir](https://github.com/Vdimir))
+* Remove legacy `asterisk_left_columns_only` setting (it was disabled by default).
+  [#7335](https://github.com/ClickHouse/ClickHouse/pull/7335) ([Artem
+Zuikov](https://github.com/4ertus2))
+* Format strings for Template data format are now specified in files.
+  [#7118](https://github.com/ClickHouse/ClickHouse/pull/7118)
+([tavplubix](https://github.com/tavplubix))
+
+### New Feature
+* Introduce uniqCombined64() to calculate cardinality greater than UINT_MAX.
+  [#7213](https://github.com/ClickHouse/ClickHouse/pull/7213),
+[#7222](https://github.com/ClickHouse/ClickHouse/pull/7222) ([Azat
+Khuzhin](https://github.com/azat))
+* Support Bloom filter indexes on Array columns.
+  [#6984](https://github.com/ClickHouse/ClickHouse/pull/6984)
+([achimbab](https://github.com/achimbab))
+* Add a function `getMacro(name)` that returns String with the value of corresponding `<macros>`
+  from server configuration.  [#7240](https://github.com/ClickHouse/ClickHouse/pull/7240)
+([alexey-milovidov](https://github.com/alexey-milovidov))
+* Set two configuration options for a dictionary based on an HTTP source: `credentials` and
+  `http-headers`. [#7092](https://github.com/ClickHouse/ClickHouse/pull/7092) ([Guillaume
+Tassery](https://github.com/YiuRULE))
+* Add a new ProfileEvent `Merge` that counts the number of launched background merges.
+  [#7093](https://github.com/ClickHouse/ClickHouse/pull/7093) ([Mikhail
+Korotov](https://github.com/millb))
+* Add fullHostName function that returns a fully qualified domain name.
+  [#7263](https://github.com/ClickHouse/ClickHouse/issues/7263)
+[#7291](https://github.com/ClickHouse/ClickHouse/pull/7291) ([sundyli](https://github.com/sundy-li))
+* Add function `arraySplit` and `arrayReverseSplit` which split an array by "cut off"
+  conditions. They are useful in time sequence handling.
+[#7294](https://github.com/ClickHouse/ClickHouse/pull/7294) ([hcz](https://github.com/hczhcz))
+* Add new functions that return the Array of all matched indices in multiMatch family of functions.
+  [#7299](https://github.com/ClickHouse/ClickHouse/pull/7299) ([Danila
+Kutenin](https://github.com/danlark1))
+* Add a new database engine `Lazy` that is optimized for storing a large number of small -Log
+  tables.  [#7171](https://github.com/ClickHouse/ClickHouse/pull/7171) ([Nikita
+Vasilev](https://github.com/nikvas0))
+* Add aggregate functions groupBitmapAnd, -Or, -Xor for bitmap columns. [#7109](https://github.com/ClickHouse/ClickHouse/pull/7109) ([Zhichang
+Yu](https://github.com/yuzhichang))
+* Add aggregate function combinators -OrNull and -OrDefault, which return null
+  or default values when there is nothing to aggregate.
+[#7331](https://github.com/ClickHouse/ClickHouse/pull/7331)
+([hcz](https://github.com/hczhcz))
+* Introduce CustomSeparated data format that supports custom escaping and
+  delimiter rules.  [#7118](https://github.com/ClickHouse/ClickHouse/pull/7118)
+([tavplubix](https://github.com/tavplubix))
+
+### Bug Fix
+* Fix wrong query result if it has `WHERE IN (SELECT ...)` section and `optimize_read_in_order` is
+  used. [#7371](https://github.com/ClickHouse/ClickHouse/pull/7371) ([Anton
+Popov](https://github.com/CurtizJ))
+* Disabled MariaDB authentication plugin, which depends on files outside of project.
+  [#7140](https://github.com/ClickHouse/ClickHouse/pull/7140) ([Yuriy
+Baranov](https://github.com/yurriy))
+* Fix exception `Cannot convert column ... because it is constant but values of constants are
+  different in source and result` which could rarely happen when functions `now()`, `today()`,
+`yesterday()`, `randConstant()` are used.
+[#7156](https://github.com/ClickHouse/ClickHouse/pull/7156) ([Nikolai
+Kochetov](https://github.com/KochetovNicolai))
+* Fixed issue of using HTTP keep alive timeout instead of TCP keep alive timeout.
+  [#7351](https://github.com/ClickHouse/ClickHouse/pull/7351) ([Vasily
+Nemkov](https://github.com/Enmk))
+* Fixed a segmentation fault in groupBitmapOr (issue [#7109](https://github.com/ClickHouse/ClickHouse/issues/7109)).
+  [#7289](https://github.com/ClickHouse/ClickHouse/pull/7289) ([Zhichang
+Yu](https://github.com/yuzhichang))
+* For materialized views the commit for Kafka is called after all data were written.
+  [#7175](https://github.com/ClickHouse/ClickHouse/pull/7175) ([Ivan](https://github.com/abyss7))
+* Fixed wrong `duration_ms` value in `system.part_log` table. It was ten times off.
+  [#7172](https://github.com/ClickHouse/ClickHouse/pull/7172) ([Vladimir
+Chebotarev](https://github.com/excitoon))
+* A quick fix to resolve crash in LIVE VIEW table and re-enabling all LIVE VIEW tests.
+  [#7201](https://github.com/ClickHouse/ClickHouse/pull/7201)
+([vzakaznikov](https://github.com/vzakaznikov))
+* Serialize NULL values correctly in min/max indexes of MergeTree parts.
+  [#7234](https://github.com/ClickHouse/ClickHouse/pull/7234) ([Alexander
+Kuzmenkov](https://github.com/akuzm))
+* Don't put virtual columns to .sql metadata when table is created as `CREATE TABLE AS`.
+  [#7183](https://github.com/ClickHouse/ClickHouse/pull/7183) ([Ivan](https://github.com/abyss7))
+* Fix segmentation fault in `ATTACH PART` query.
+  [#7185](https://github.com/ClickHouse/ClickHouse/pull/7185)
+([alesapin](https://github.com/alesapin))
+* Fix wrong result for some queries given by the optimization of empty IN subqueries and empty
+  INNER/RIGHT JOIN. [#7284](https://github.com/ClickHouse/ClickHouse/pull/7284) ([Nikolai
+Kochetov](https://github.com/KochetovNicolai))
+* Fixing AddressSanitizer error in the LIVE VIEW getHeader() method.
+  [#7271](https://github.com/ClickHouse/ClickHouse/pull/7271)
+([vzakaznikov](https://github.com/vzakaznikov))
+
+### Improvement
+* Add a message in case of queue_wait_max_ms wait takes place.
+  [#7390](https://github.com/ClickHouse/ClickHouse/pull/7390) ([Azat
+Khuzhin](https://github.com/azat))
+* Made setting `s3_min_upload_part_size` table-level.
+  [#7059](https://github.com/ClickHouse/ClickHouse/pull/7059) ([Vladimir
+Chebotarev](https://github.com/excitoon))
+* Check TTL in StorageFactory. [#7304](https://github.com/ClickHouse/ClickHouse/pull/7304)
+  ([sundyli](https://github.com/sundy-li))
+* Squash left-hand blocks in partial merge join (optimization).
+  [#7122](https://github.com/ClickHouse/ClickHouse/pull/7122) ([Artem
+Zuikov](https://github.com/4ertus2))
+* Do not allow non-deterministic functions in mutations of Replicated table engines, because this
+  can introduce inconsistencies between replicas.
+[#7247](https://github.com/ClickHouse/ClickHouse/pull/7247) ([Alexander
+Kazakov](https://github.com/Akazz))
+* Disable memory tracker while converting exception stack trace to string. It can prevent the loss
+  of error messages of type `Memory limit exceeded` on server, which caused the `Attempt to read
+after eof` exception on client. [#7264](https://github.com/ClickHouse/ClickHouse/pull/7264)
+([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Miscellaneous format improvements. Resolves
+  [#6033](https://github.com/ClickHouse/ClickHouse/issues/6033),
+[#2633](https://github.com/ClickHouse/ClickHouse/issues/2633),
+[#6611](https://github.com/ClickHouse/ClickHouse/issues/6611),
+[#6742](https://github.com/ClickHouse/ClickHouse/issues/6742)
+[#7215](https://github.com/ClickHouse/ClickHouse/pull/7215)
+([tavplubix](https://github.com/tavplubix))
+* ClickHouse ignores values on the right side of IN operator that are not convertible to the left
+  side type. Make it work properly for compound types -- Array and Tuple.
+[#7283](https://github.com/ClickHouse/ClickHouse/pull/7283) ([Alexander
+Kuzmenkov](https://github.com/akuzm))
+* Support missing inequalities for ASOF JOIN. It's possible to join less-or-equal variant and strict
+  greater and less variants for ASOF column in ON syntax.
+[#7282](https://github.com/ClickHouse/ClickHouse/pull/7282) ([Artem
+Zuikov](https://github.com/4ertus2))
+* Optimize partial merge join. [#7070](https://github.com/ClickHouse/ClickHouse/pull/7070)
+  ([Artem Zuikov](https://github.com/4ertus2))
+* Do not use more then 98K of memory in uniqCombined functions.
+  [#7236](https://github.com/ClickHouse/ClickHouse/pull/7236),
+[#7270](https://github.com/ClickHouse/ClickHouse/pull/7270) ([Azat
+Khuzhin](https://github.com/azat))
+* Flush parts of right-hand joining table on disk in PartialMergeJoin (if there is not enough
+  memory). Load data back when needed.  [#7186](https://github.com/ClickHouse/ClickHouse/pull/7186)
+([Artem Zuikov](https://github.com/4ertus2))
+
+### Performance Improvement
+* Speed up joinGet with const arguments by avoiding data duplication.
+  [#7359](https://github.com/ClickHouse/ClickHouse/pull/7359) ([Amos
+Bird](https://github.com/amosbird))
+* Return early if the subquery is empty.
+  [#7007](https://github.com/ClickHouse/ClickHouse/pull/7007) ([小路](https://github.com/nicelulu))
+* Optimize parsing of SQL expression in Values.
+  [#6781](https://github.com/ClickHouse/ClickHouse/pull/6781)
+([tavplubix](https://github.com/tavplubix))
+
+### Build/Testing/Packaging Improvement
+* Disable some contribs for cross-compilation to Mac OS.
+  [#7101](https://github.com/ClickHouse/ClickHouse/pull/7101) ([Ivan](https://github.com/abyss7))
+* Add missing linking with PocoXML for clickhouse_common_io.
+  [#7200](https://github.com/ClickHouse/ClickHouse/pull/7200) ([Azat
+Khuzhin](https://github.com/azat))
+* Accept multiple test filter arguments in clickhouse-test.
+  [#7226](https://github.com/ClickHouse/ClickHouse/pull/7226) ([Alexander
+Kuzmenkov](https://github.com/akuzm))
+* Enable musl and jemalloc for ARM.  [#7300](https://github.com/ClickHouse/ClickHouse/pull/7300)
+  ([Amos Bird](https://github.com/amosbird))
+* Added `--client-option` parameter to `clickhouse-test` to pass additional parameters to client.
+  [#7277](https://github.com/ClickHouse/ClickHouse/pull/7277) ([Nikolai
+Kochetov](https://github.com/KochetovNicolai))
+* Preserve existing configs on rpm package upgrade.
+  [#7103](https://github.com/ClickHouse/ClickHouse/pull/7103)
+([filimonov](https://github.com/filimonov))
+* Fix errors detected by PVS. [#7153](https://github.com/ClickHouse/ClickHouse/pull/7153) ([Artem
+  Zuikov](https://github.com/4ertus2))
+* Fix build for Darwin. [#7149](https://github.com/ClickHouse/ClickHouse/pull/7149)
+  ([Ivan](https://github.com/abyss7))
+* glibc 2.29 compatibility. [#7142](https://github.com/ClickHouse/ClickHouse/pull/7142) ([Amos
+  Bird](https://github.com/amosbird))
+* Make sure dh_clean does not touch potential source files.
+  [#7205](https://github.com/ClickHouse/ClickHouse/pull/7205) ([Amos
+Bird](https://github.com/amosbird))
+* Attempt to avoid conflict when updating from altinity rpm - it has config file packaged separately
+  in clickhouse-server-common.  [#7073](https://github.com/ClickHouse/ClickHouse/pull/7073)
+([filimonov](https://github.com/filimonov))
+* Optimize some header files for faster rebuilds.
+  [#7212](https://github.com/ClickHouse/ClickHouse/pull/7212),
+[#7231](https://github.com/ClickHouse/ClickHouse/pull/7231) ([Alexander
+Kuzmenkov](https://github.com/akuzm))
+* Add performance tests for Date and DateTime. [#7332](https://github.com/ClickHouse/ClickHouse/pull/7332) ([Vasily
+  Nemkov](https://github.com/Enmk))
+* Fix some tests that contained non-deterministic mutations.
+  [#7132](https://github.com/ClickHouse/ClickHouse/pull/7132) ([Alexander
+Kazakov](https://github.com/Akazz))
+* Add build with MemorySanitizer to CI.  [#7066](https://github.com/ClickHouse/ClickHouse/pull/7066)
+  ([Alexander Kuzmenkov](https://github.com/akuzm))
+* Avoid use of uninitialized values in MetricsTransmitter.
+  [#7158](https://github.com/ClickHouse/ClickHouse/pull/7158) ([Azat
+Khuzhin](https://github.com/azat))
+* Fix some issues in Fields found by MemorySanitizer.
+  [#7135](https://github.com/ClickHouse/ClickHouse/pull/7135),
+[#7179](https://github.com/ClickHouse/ClickHouse/pull/7179) ([Alexander
+Kuzmenkov](https://github.com/akuzm)), [#7376](https://github.com/ClickHouse/ClickHouse/pull/7376)
+([Amos Bird](https://github.com/amosbird))
+* Fix undefined behavior in murmurhash32. [#7388](https://github.com/ClickHouse/ClickHouse/pull/7388) ([Amos
+  Bird](https://github.com/amosbird))
+* Fix undefined behavior in StoragesInfoStream. [#7384](https://github.com/ClickHouse/ClickHouse/pull/7384)
+  ([tavplubix](https://github.com/tavplubix))
+* Fixed constant expressions folding for external database engines (MySQL, ODBC, JDBC). In previous
+  versions it wasn't working for multiple constant expressions and was not working at all for Date,
+DateTime and UUID. This fixes [#7245](https://github.com/ClickHouse/ClickHouse/issues/7245)
+[#7252](https://github.com/ClickHouse/ClickHouse/pull/7252)
+([alexey-milovidov](https://github.com/alexey-milovidov))
+* Fixing ThreadSanitizer data race error in the LIVE VIEW when accessing no_users_thread variable.
+  [#7353](https://github.com/ClickHouse/ClickHouse/pull/7353)
+([vzakaznikov](https://github.com/vzakaznikov))
+* Get rid of malloc symbols in libcommon
+  [#7134](https://github.com/ClickHouse/ClickHouse/pull/7134),
+[#7065](https://github.com/ClickHouse/ClickHouse/pull/7065) ([Amos
+Bird](https://github.com/amosbird))
+* Add global flag ENABLE_LIBRARIES for disabling all libraries.
+  [#7063](https://github.com/ClickHouse/ClickHouse/pull/7063)
+([proller](https://github.com/proller))
+
+### Code cleanup
+* Generalize configuration repository to prepare for DDL for Dictionaries.  [#7155](https://github.com/ClickHouse/ClickHouse/pull/7155)
+  ([alesapin](https://github.com/alesapin))
+* Parser for dictionaries DDL without any semantic.
+  [#7209](https://github.com/ClickHouse/ClickHouse/pull/7209)
+([alesapin](https://github.com/alesapin))
+* Split ParserCreateQuery into different smaller parsers.
+  [#7253](https://github.com/ClickHouse/ClickHouse/pull/7253)
+([alesapin](https://github.com/alesapin))
+* Small refactoring and renaming near external dictionaries.
+  [#7111](https://github.com/ClickHouse/ClickHouse/pull/7111)
+([alesapin](https://github.com/alesapin))
+* Refactor some code to prepare for role-based access control. [#7235](https://github.com/ClickHouse/ClickHouse/pull/7235) ([Vitaly
+  Baranov](https://github.com/vitlibar))
+* Some improvements in DatabaseOrdinary code.
+  [#7086](https://github.com/ClickHouse/ClickHouse/pull/7086) ([Nikita
+Vasilev](https://github.com/nikvas0))
+* Do not use iterators in find() and emplace() methods of hash tables.
+[#7026](https://github.com/ClickHouse/ClickHouse/pull/7026) ([Alexander
+Kuzmenkov](https://github.com/akuzm))
+* Fix getMultipleValuesFromConfig in case when parameter root is not empty. [#7374](https://github.com/ClickHouse/ClickHouse/pull/7374)
+([Mikhail Korotov](https://github.com/millb))
+* Remove some copy-paste (TemporaryFile and TemporaryFileStream)
+  [#7166](https://github.com/ClickHouse/ClickHouse/pull/7166) ([Artem
+Zuikov](https://github.com/4ertus2))
+* Improved code readability a little bit (`MergeTreeData::getActiveContainingPart`).
+  [#7361](https://github.com/ClickHouse/ClickHouse/pull/7361) ([Vladimir
+Chebotarev](https://github.com/excitoon))
+* Wait for all scheduled jobs, which are using local objects, if `ThreadPool::schedule(...)` throws
+  an exception. Rename `ThreadPool::schedule(...)` to `ThreadPool::scheduleOrThrowOnError(...)` and
+fix comments to make obvious that it may throw.
+[#7350](https://github.com/ClickHouse/ClickHouse/pull/7350)
+([tavplubix](https://github.com/tavplubix))
+
+## ClickHouse release 19.15.4.10, 2019-10-31
+
+### Bug Fix
+* Added handling of SQL_TINYINT and SQL_BIGINT, and fix handling of SQL_FLOAT data source types in ODBC Bridge.
+[#7491](https://github.com/ClickHouse/ClickHouse/pull/7491) ([Denis Glazachev](https://github.com/traceon))
+* Allowed to have some parts on destination disk or volume in MOVE PARTITION.
+[#7434](https://github.com/ClickHouse/ClickHouse/pull/7434) ([Vladimir Chebotarev](https://github.com/excitoon))
+* Fixed NULL-values in nullable columns through ODBC-bridge.
+[#7402](https://github.com/ClickHouse/ClickHouse/pull/7402) ([Vasily Nemkov](https://github.com/Enmk))
+* Fixed INSERT into Distributed non local node with MATERIALIZED columns.
+[#7377](https://github.com/ClickHouse/ClickHouse/pull/7377) ([Azat Khuzhin](https://github.com/azat))
+* Fixed function getMultipleValuesFromConfig.
+[#7374](https://github.com/ClickHouse/ClickHouse/pull/7374) ([Mikhail Korotov](https://github.com/millb))
+* Fixed issue of using HTTP keep alive timeout instead of TCP keep alive timeout.
+[#7351](https://github.com/ClickHouse/ClickHouse/pull/7351) ([Vasily Nemkov](https://github.com/Enmk))
+* Wait for all jobs to finish on exception (fixes rare segfaults).
+[#7350](https://github.com/ClickHouse/ClickHouse/pull/7350) ([tavplubix](https://github.com/tavplubix))
+* Don't push to MVs when inserting into Kafka table.
+[#7265](https://github.com/ClickHouse/ClickHouse/pull/7265) ([Ivan](https://github.com/abyss7))
+* Disable memory tracker for exception stack.
+[#7264](https://github.com/ClickHouse/ClickHouse/pull/7264) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
+* Fixed bad code in transforming query for external database.
+[#7252](https://github.com/ClickHouse/ClickHouse/pull/7252) ([alexey-milovidov](https://github.com/alexey-milovidov))
+* Avoid use of uninitialized values in MetricsTransmitter.
+[#7158](https://github.com/ClickHouse/ClickHouse/pull/7158) ([Azat Khuzhin](https://github.com/azat))
+* Added example config with macros for tests ([alexey-milovidov](https://github.com/alexey-milovidov))
+
+## ClickHouse release 19.15.3.6, 2019-10-09
+
+### Bug Fix
+* Fixed bad_variant in hashed dictionary.
+([alesapin](https://github.com/alesapin))
+* Fixed up bug with segmentation fault in ATTACH PART query.
+([alesapin](https://github.com/alesapin))
+* Fixed time calculation in `MergeTreeData`.
+([Vladimir Chebotarev](https://github.com/excitoon))
+* Commit to Kafka explicitly after the writing is finalized.
+[#7175](https://github.com/ClickHouse/ClickHouse/pull/7175) ([Ivan](https://github.com/abyss7))
+* Serialize NULL values correctly in min/max indexes of MergeTree parts.
+[#7234](https://github.com/ClickHouse/ClickHouse/pull/7234) ([Alexander Kuzmenkov](https://github.com/akuzm))
+
 ## ClickHouse release 19.15.2.2, 2019-10-01

 ### New Feature
@ -345,6 +636,13 @@
 ### Security Fix
 * Fix two vulnerabilities in codecs in decompression phase (malicious user can fabricate compressed data that will lead to buffer overflow in decompression). [#6670](https://github.com/ClickHouse/ClickHouse/pull/6670) ([Artem Zuikov](https://github.com/4ertus2))

+## ClickHouse release 19.11.13.74, 2019-11-01
+
+### Bug Fix
+* Fixed rare crash in `ALTER MODIFY COLUMN` and vertical merge when one of merged/altered parts is empty (0 rows). [#6780](https://github.com/ClickHouse/ClickHouse/pull/6780) ([alesapin](https://github.com/alesapin))
+* Manual update of `SIMDJSON`. This fixes possible flooding of stderr files with bogus json diagnostic messages. [#7548](https://github.com/ClickHouse/ClickHouse/pull/7548) ([Alexander Kazakov](https://github.com/Akazz))
+* Fixed bug with `mrk` file extension for mutations ([alesapin](https://github.com/alesapin))
+
 ## ClickHouse release 19.11.12.69, 2019-10-02

 ### Bug Fix
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@ -13,7 +13,10 @@ foreach(policy
 endforeach()

 project(ClickHouse)
+
+include (cmake/arch.cmake)
 include (cmake/target.cmake)
+include (cmake/tools.cmake)

 # Ignore export() since we don't use it,
 # but it gets broken with a global targets via link_libraries()
@ -26,8 +29,6 @@ set(CMAKE_LINK_DEPENDS_NO_SHARED 1) # Do not relink all depended targets on .so
 set(CMAKE_CONFIGURATION_TYPES "RelWithDebInfo;Debug;Release;MinSizeRel" CACHE STRING "" FORCE)
 set(CMAKE_DEBUG_POSTFIX "d" CACHE STRING "Generate debug library name with a postfix.")    # To be consistent with CMakeLists from contrib libs.

-include (cmake/arch.cmake)
-
 option(ENABLE_IPO "Enable inter-procedural optimization (aka LTO)" OFF) # need cmake 3.9+
 if(ENABLE_IPO)
    cmake_policy(SET CMP0069 NEW)
@ -230,7 +231,6 @@ include(cmake/dbms_glob_sources.cmake)
 if (OS_LINUX)
    include(cmake/linux/default_libs.cmake)
 elseif (OS_DARWIN)
-    include(cmake/darwin/sdk.cmake)
    include(cmake/darwin/default_libs.cmake)
 endif ()

--- a/README.md
+++ b/README.md
@ -13,8 +13,9 @@ ClickHouse is an open-source column-oriented database management system that all
 * You can also [fill this form](https://forms.yandex.com/surveys/meet-yandex-clickhouse-team/) to meet Yandex ClickHouse team in person.

 ## Upcoming Events
-* [ClickHouse Meetup in Shanghai](https://www.huodongxing.com/event/4483760336000) on October 27.
 * [ClickHouse Meetup in Tokyo](https://clickhouse.connpass.com/event/147001/) on November 14.
 * [ClickHouse Meetup in Istanbul](https://www.eventbrite.com/e/clickhouse-meetup-istanbul-create-blazing-fast-experiences-w-clickhouse-tickets-73101120419) on November 19.
 * [ClickHouse Meetup in Ankara](https://www.eventbrite.com/e/clickhouse-meetup-ankara-create-blazing-fast-experiences-w-clickhouse-tickets-73100530655) on November 21.
 * [ClickHouse Meetup in Singapore](https://www.meetup.com/Singapore-Clickhouse-Meetup-Group/events/265085331/) on November 23.
+* [ClickHouse Meetup in San Francisco](https://www.eventbrite.com/e/clickhouse-december-meetup-registration-78642047481) on December 3.
+
--- a/cmake/arch.cmake
+++ b/cmake/arch.cmake
@ -17,6 +17,7 @@ endif ()

 if (CMAKE_SYSTEM_PROCESSOR MATCHES "^(ppc64le.*|PPC64LE.*)")
    set (ARCH_PPC64LE 1)
+    # FIXME: move this check into tools.cmake
    if (COMPILER_CLANG OR (COMPILER_GCC AND CMAKE_CXX_COMPILER_VERSION VERSION_LESS 8))
        message(FATAL_ERROR "Only gcc-8 is supported for powerpc architecture")
    endif ()
--- a/cmake/darwin/default_libs.cmake
+++ b/cmake/darwin/default_libs.cmake
@ -11,6 +11,14 @@ message(STATUS "Default libraries: ${DEFAULT_LIBS}")
 set(CMAKE_CXX_STANDARD_LIBRARIES ${DEFAULT_LIBS})
 set(CMAKE_C_STANDARD_LIBRARIES ${DEFAULT_LIBS})

+# Minimal supported SDK version
+
+set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -mmacosx-version-min=10.14")
+set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mmacosx-version-min=10.14")
+
+set (CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -mmacosx-version-min=10.14")
+set (CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -mmacosx-version-min=10.14")
+
 # Global libraries

 add_library(global-libs INTERFACE)
--- a/cmake/darwin/sdk.cmake
+++ b/cmake/darwin/sdk.cmake
@ -1,11 +0,0 @@
-option (SDK_PATH "Path to the SDK to build with" "")
-
-if (NOT EXISTS "${SDK_PATH}/SDKSettings.plist")
-    message (FATAL_ERROR "Wrong SDK path provided: ${SDK_PATH}")
-endif ()
-
-set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -isysroot ${SDK_PATH} -mmacosx-version-min=10.14")
-set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -isysroot ${SDK_PATH} -mmacosx-version-min=10.14")
-
-set (CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -isysroot ${SDK_PATH} -mmacosx-version-min=10.14")
-set (CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -isysroot ${SDK_PATH} -mmacosx-version-min=10.14")
--- a/cmake/darwin/toolchain-x86_64.cmake
+++ b/cmake/darwin/toolchain-x86_64.cmake
@ -0,0 +1,13 @@
+set (CMAKE_SYSTEM_NAME "Darwin")
+set (CMAKE_SYSTEM_PROCESSOR "x86_64")
+set (CMAKE_C_COMPILER_TARGET "x86_64-apple-darwin")
+set (CMAKE_CXX_COMPILER_TARGET "x86_64-apple-darwin")
+set (CMAKE_OSX_SYSROOT "${CMAKE_CURRENT_LIST_DIR}/../toolchain/darwin-x86_64")
+
+set (CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)  # disable linkage check - it doesn't work in CMake
+
+set (HAS_PRE_1970_EXITCODE "0" CACHE STRING "Result from TRY_RUN" FORCE)
+set (HAS_PRE_1970_EXITCODE__TRYRUN_OUTPUT "" CACHE STRING "Output from TRY_RUN" FORCE)
+
+set (HAS_POST_2038_EXITCODE "0" CACHE STRING "Result from TRY_RUN" FORCE)
+set (HAS_POST_2038_EXITCODE__TRYRUN_OUTPUT "" CACHE STRING "Output from TRY_RUN" FORCE)
--- a/cmake/dbms_glob_sources.cmake
+++ b/cmake/dbms_glob_sources.cmake
@ -1,13 +1,20 @@
-macro(add_glob cur_list)
-    file(GLOB __tmp RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} ${ARGN})
-    list(APPEND ${cur_list} ${__tmp})
-endmacro()
+if (CMAKE_VERSION VERSION_GREATER_EQUAL "3.12")
+    macro(add_glob cur_list)
+        file(GLOB __tmp RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} CONFIGURE_DEPENDS ${ARGN})
+        list(APPEND ${cur_list} ${__tmp})
+    endmacro()
+else ()
+    macro(add_glob cur_list)
+        file(GLOB __tmp RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} ${ARGN})
+        list(APPEND ${cur_list} ${__tmp})
+    endmacro()
+endif ()

 macro(add_headers_and_sources prefix common_path)
-    add_glob(${prefix}_headers RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} ${common_path}/*.h)
+    add_glob(${prefix}_headers ${CMAKE_CURRENT_SOURCE_DIR} ${common_path}/*.h)
    add_glob(${prefix}_sources ${common_path}/*.cpp ${common_path}/*.c ${common_path}/*.h)
 endmacro()

 macro(add_headers_only prefix common_path)
-    add_glob(${prefix}_headers RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} ${common_path}/*.h)
+    add_glob(${prefix}_headers ${CMAKE_CURRENT_SOURCE_DIR} ${common_path}/*.h)
 endmacro()
--- a/cmake/find/capnp.cmake
+++ b/cmake/find/capnp.cmake
@ -4,6 +4,14 @@ if (ENABLE_CAPNP)

 option (USE_INTERNAL_CAPNP_LIBRARY "Set to FALSE to use system capnproto library instead of bundled" ${NOT_UNBUNDLED})

+if(NOT EXISTS "${ClickHouse_SOURCE_DIR}/contrib/capnproto/CMakeLists.txt")
+    if(USE_INTERNAL_CAPNP_LIBRARY)
+        message(WARNING "submodule contrib/capnproto is missing. to fix try run: \n git submodule update --init --recursive")
+    endif()
+    set(MISSING_INTERNAL_CAPNP_LIBRARY 1)
+    set(USE_INTERNAL_CAPNP_LIBRARY 0)
+endif()
+
 # FIXME: refactor to use `add_library(… IMPORTED)` if possible.
 if (NOT USE_INTERNAL_CAPNP_LIBRARY)
    find_library (KJ kj)
@ -11,7 +19,7 @@ if (NOT USE_INTERNAL_CAPNP_LIBRARY)
    find_library (CAPNPC capnpc)

    set (CAPNP_LIBRARIES ${CAPNPC} ${CAPNP} ${KJ})
-else ()
+elseif(NOT MISSING_INTERNAL_CAPNP_LIBRARY)
    add_subdirectory(contrib/capnproto-cmake)

    set (CAPNP_LIBRARIES capnpc)
@ -23,4 +31,4 @@ endif ()

 endif ()

-message (STATUS "Using capnp: ${CAPNP_LIBRARIES}")
+message (STATUS "Using capnp=${USE_CAPNP}: ${CAPNP_LIBRARIES}")
--- a/cmake/find/orc.cmake
+++ b/cmake/find/orc.cmake
@ -1,7 +1,8 @@
 option (ENABLE_ORC "Enable ORC" ${ENABLE_LIBRARIES})

 if(ENABLE_ORC)
-option (USE_INTERNAL_ORC_LIBRARY "Set to FALSE to use system ORC instead of bundled" ${NOT_UNBUNDLED})
+include(cmake/find/snappy.cmake)
+option(USE_INTERNAL_ORC_LIBRARY "Set to FALSE to use system ORC instead of bundled" ${NOT_UNBUNDLED})

 if (NOT EXISTS "${ClickHouse_SOURCE_DIR}/contrib/orc/c++/include/orc/OrcFile.hh")
   if(USE_INTERNAL_ORC_LIBRARY)
@ -25,7 +26,7 @@ endif ()

 if (ORC_LIBRARY AND ORC_INCLUDE_DIR)
    set(USE_ORC 1)
-elseif(NOT MISSING_INTERNAL_ORC_LIBRARY AND ARROW_LIBRARY) # (LIBGSASL_LIBRARY AND LIBXML2_LIBRARY)
+elseif(NOT MISSING_INTERNAL_ORC_LIBRARY AND ARROW_LIBRARY AND SNAPPY_LIBRARY) # (LIBGSASL_LIBRARY AND LIBXML2_LIBRARY)
    set(ORC_INCLUDE_DIR "${ClickHouse_SOURCE_DIR}/contrib/orc/c++/include")
    set(ORC_LIBRARY orc)
    set(USE_ORC 1)
--- a/cmake/find/parquet.cmake
+++ b/cmake/find/parquet.cmake
@ -24,7 +24,10 @@ endif()
 if(ARROW_INCLUDE_DIR AND PARQUET_INCLUDE_DIR)
 elseif(NOT MISSING_INTERNAL_PARQUET_LIBRARY AND NOT OS_FREEBSD)
    include(cmake/find/snappy.cmake)
-    set(CAN_USE_INTERNAL_PARQUET_LIBRARY 1)
+    if(SNAPPY_LIBRARY)
+        set(CAN_USE_INTERNAL_PARQUET_LIBRARY 1)
+    endif()
+
    include(CheckCXXSourceCompiles)
    if(NOT USE_INTERNAL_DOUBLE_CONVERSION_LIBRARY)
        set(CMAKE_REQUIRED_LIBRARIES ${DOUBLE_CONVERSION_LIBRARIES})
--- a/cmake/find/poco.cmake
+++ b/cmake/find/poco.cmake
@ -8,6 +8,14 @@ if (NOT EXISTS "${ClickHouse_SOURCE_DIR}/contrib/poco/CMakeLists.txt")
   set (MISSING_INTERNAL_POCO_LIBRARY 1)
 endif ()

+if (NOT ENABLE_LIBRARIES)
+    set (ENABLE_POCO_NETSSL ${ENABLE_LIBRARIES} CACHE BOOL "")
+    set (ENABLE_POCO_MONGODB ${ENABLE_LIBRARIES} CACHE BOOL "")
+    set (ENABLE_POCO_REDIS ${ENABLE_LIBRARIES} CACHE BOOL "")
+    set (ENABLE_POCO_ODBC ${ENABLE_LIBRARIES} CACHE BOOL "")
+    set (ENABLE_POCO_SQL ${ENABLE_LIBRARIES} CACHE BOOL "")
+endif ()
+
 set (POCO_COMPONENTS Net XML SQL Data)
 if (NOT DEFINED ENABLE_POCO_NETSSL OR ENABLE_POCO_NETSSL)
    list (APPEND POCO_COMPONENTS Crypto NetSSL)
--- a/cmake/find/unwind.cmake
+++ b/cmake/find/unwind.cmake
@ -4,6 +4,11 @@ if (NOT CMAKE_SYSTEM MATCHES "Linux" OR ARCH_ARM OR ARCH_32)
    set (USE_UNWIND OFF)
 endif ()

+if (NOT EXISTS "${ClickHouse_SOURCE_DIR}/contrib/libunwind/CMakeLists.txt")
+    message(WARNING "submodule contrib/libunwind is missing. to fix try run: \n git submodule update --init --recursive")
+    set (USE_UNWIND OFF)
+endif ()
+
 if (USE_UNWIND)
    add_subdirectory(contrib/libunwind-cmake)
    set (UNWIND_LIBRARIES unwind)
--- a/cmake/linux/default_libs.cmake
+++ b/cmake/linux/default_libs.cmake
@ -5,7 +5,7 @@ set (DEFAULT_LIBS "-nodefaultlibs")

 # We need builtins from Clang's RT even without libcxx - for ubsan+int128.
 # See https://bugs.llvm.org/show_bug.cgi?id=16404
-if (COMPILER_CLANG)
+if (COMPILER_CLANG AND NOT (CMAKE_CROSSCOMPILING AND ARCH_AARCH64))
    execute_process (COMMAND ${CMAKE_CXX_COMPILER} --print-file-name=libclang_rt.builtins-${CMAKE_SYSTEM_PROCESSOR}.a OUTPUT_VARIABLE BUILTINS_LIBRARY OUTPUT_STRIP_TRAILING_WHITESPACE)
 else ()
    set (BUILTINS_LIBRARY "-lgcc")
--- a/cmake/linux/toolchain-aarch64.cmake
+++ b/cmake/linux/toolchain-aarch64.cmake
@ -0,0 +1,25 @@
+set (CMAKE_SYSTEM_NAME "Linux")
+set (CMAKE_SYSTEM_PROCESSOR "aarch64")
+set (CMAKE_C_COMPILER_TARGET "aarch64-linux-gnu")
+set (CMAKE_CXX_COMPILER_TARGET "aarch64-linux-gnu")
+set (CMAKE_ASM_COMPILER_TARGET "aarch64-linux-gnu")
+set (CMAKE_SYSROOT "${CMAKE_CURRENT_LIST_DIR}/../toolchain/linux-aarch64/aarch64-linux-gnu/libc")
+
+# We don't use compiler from toolchain because it's gcc-8, and we provide support only for gcc-9.
+set (CMAKE_AR "${CMAKE_CURRENT_LIST_DIR}/../toolchain/linux-aarch64/bin/aarch64-linux-gnu-ar" CACHE FILEPATH "" FORCE)
+set (CMAKE_RANLIB "${CMAKE_CURRENT_LIST_DIR}/../toolchain/linux-aarch64/bin/aarch64-linux-gnu-ranlib" CACHE FILEPATH "" FORCE)
+
+set (CMAKE_C_FLAGS_INIT "${CMAKE_C_FLAGS} --gcc-toolchain=${CMAKE_CURRENT_LIST_DIR}/../toolchain/linux-aarch64")
+set (CMAKE_CXX_FLAGS_INIT "${CMAKE_CXX_FLAGS} --gcc-toolchain=${CMAKE_CURRENT_LIST_DIR}/../toolchain/linux-aarch64")
+set (CMAKE_ASM_FLAGS_INIT "${CMAKE_ASM_FLAGS} --gcc-toolchain=${CMAKE_CURRENT_LIST_DIR}/../toolchain/linux-aarch64")
+
+set (LINKER_NAME "lld" CACHE STRING "" FORCE)
+
+set (CMAKE_EXE_LINKER_FLAGS_INIT "-fuse-ld=lld")
+set (CMAKE_SHARED_LINKER_FLAGS_INIT "-fuse-ld=lld")
+
+set (HAS_PRE_1970_EXITCODE "0" CACHE STRING "Result from TRY_RUN" FORCE)
+set (HAS_PRE_1970_EXITCODE__TRYRUN_OUTPUT "" CACHE STRING "Output from TRY_RUN" FORCE)
+
+set (HAS_POST_2038_EXITCODE "0" CACHE STRING "Result from TRY_RUN" FORCE)
+set (HAS_POST_2038_EXITCODE__TRYRUN_OUTPUT "" CACHE STRING "Output from TRY_RUN" FORCE)
--- a/cmake/target.cmake
+++ b/cmake/target.cmake
@ -9,62 +9,8 @@ elseif (CMAKE_SYSTEM_NAME MATCHES "Darwin")
    add_definitions(-D OS_DARWIN)
 endif ()

-if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
-    set (COMPILER_GCC 1)
-elseif (CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
-    set (COMPILER_CLANG 1)
-endif ()
-
-if (COMPILER_GCC)
-    # Require minimum version of gcc
-    set (GCC_MINIMUM_VERSION 8)
-    if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS ${GCC_MINIMUM_VERSION} AND NOT CMAKE_VERSION VERSION_LESS 2.8.9)
-        message (FATAL_ERROR "GCC version must be at least ${GCC_MINIMUM_VERSION}. For example, if GCC ${GCC_MINIMUM_VERSION} is available under gcc-${GCC_MINIMUM_VERSION}, g++-${GCC_MINIMUM_VERSION} names, do the following: export CC=gcc-${GCC_MINIMUM_VERSION} CXX=g++-${GCC_MINIMUM_VERSION}; rm -rf CMakeCache.txt CMakeFiles; and re run cmake or ./release.")
-    endif ()
-elseif (COMPILER_CLANG)
-    # Require minimum version of clang
-    set (CLANG_MINIMUM_VERSION 7)
-    if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS ${CLANG_MINIMUM_VERSION})
-        message (FATAL_ERROR "Clang version must be at least ${CLANG_MINIMUM_VERSION}.")
-    endif ()
-else ()
-    message (WARNING "You are using an unsupported compiler. Compilation has only been tested with Clang 6+ and GCC 7+.")
-endif ()
-
-string(REGEX MATCH "-?[0-9]+(.[0-9]+)?$" COMPILER_POSTFIX ${CMAKE_CXX_COMPILER})
-
-if (OS_LINUX)
-    find_program (LLD_PATH NAMES "lld${COMPILER_POSTFIX}" "lld")
-    find_program (GOLD_PATH NAMES "ld.gold" "gold")
-endif()
-
-option (LINKER_NAME "Linker name or full path")
-if (NOT LINKER_NAME)
-    if (COMPILER_CLANG AND LLD_PATH)
-        set (LINKER_NAME "lld")
-    elseif (GOLD_PATH)
-        set (LINKER_NAME "gold")
-    endif ()
-endif ()
-
-if (LINKER_NAME)
-    message(STATUS "Using linker: ${LINKER_NAME} (selected from: LLD_PATH=${LLD_PATH}; GOLD_PATH=${GOLD_PATH}; COMPILER_POSTFIX=${COMPILER_POSTFIX})")
-    set (CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -fuse-ld=${LINKER_NAME}")
-    set (CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -fuse-ld=${LINKER_NAME}")
-endif ()
-
 if (CMAKE_CROSSCOMPILING)
    if (OS_DARWIN)
-        set (CMAKE_SYSTEM_PROCESSOR x86_64)
-        set (CMAKE_C_COMPILER_TARGET x86_64-apple-darwin)
-        set (CMAKE_CXX_COMPILER_TARGET x86_64-apple-darwin)
-
-        set (HAS_PRE_1970_EXITCODE "0" CACHE STRING "Result from TRY_RUN" FORCE)
-        set (HAS_PRE_1970_EXITCODE__TRYRUN_OUTPUT "" CACHE STRING "Output from TRY_RUN" FORCE)
-
-        set (HAS_POST_2038_EXITCODE "0" CACHE STRING "Result from TRY_RUN" FORCE)
-        set (HAS_POST_2038_EXITCODE__TRYRUN_OUTPUT "" CACHE STRING "Output from TRY_RUN" FORCE)
-
        # FIXME: broken dependencies
        set (USE_SNAPPY OFF CACHE INTERNAL "")
        set (ENABLE_SSL OFF CACHE INTERNAL "")
@ -73,12 +19,19 @@ if (CMAKE_CROSSCOMPILING)
        set (ENABLE_READLINE OFF CACHE INTERNAL "")
        set (ENABLE_ICU OFF CACHE INTERNAL "")
        set (ENABLE_FASTOPS OFF CACHE INTERNAL "")
-
-        message (STATUS "Cross-compiling for Darwin")
+    elseif (OS_LINUX)
+        if (ARCH_AARCH64)
+            # FIXME: broken dependencies
+            set (ENABLE_PROTOBUF OFF CACHE INTERNAL "")
+            set (ENABLE_PARQUET OFF CACHE INTERNAL "")
+            set (ENABLE_MYSQL OFF CACHE INTERNAL "")
+        endif ()
    else ()
-        message (FATAL_ERROR "Trying to cross-compile to unsupported target: ${CMAKE_SYSTEM_NAME}!")
+        message (FATAL_ERROR "Trying to cross-compile to unsupported system: ${CMAKE_SYSTEM_NAME}!")
    endif ()

    # Don't know why but CXX_STANDARD doesn't work for cross-compilation
    set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++17")
+
+    message (STATUS "Cross-compiling for target: ${CMAKE_CXX_COMPILE_TARGET}")
 endif ()
--- a/cmake/toolchain/darwin-x86_64/README.txt
+++ b/cmake/toolchain/darwin-x86_64/README.txt
@ -0,0 +1,2 @@
+wget https://github.com/phracker/MacOSX-SDKs/releases/download/10.14-beta4/MacOSX10.14.sdk.tar.xz
+tar --strip-components=1 xJf MacOSX10.14.sdk.tar.xz
--- a/cmake/toolchain/linux-aarch64/README.txt
+++ b/cmake/toolchain/linux-aarch64/README.txt
@ -0,0 +1,2 @@
+wget https://developer.arm.com/-/media/Files/downloads/gnu-a/8.3-2019.03/binrel/gcc-arm-8.3-2019.03-x86_64-aarch64-linux-gnu.tar.xz?revision=2e88a73f-d233-4f96-b1f4-d8b36e9bb0b9&la=en -O gcc-arm-8.3-2019.03-x86_64-aarch64-linux-gnu.tar.xz
+tar --strip-components=1 xJf gcc-arm-8.3-2019.03-x86_64-aarch64-linux-gnu.tar.xz
--- a/cmake/tools.cmake
+++ b/cmake/tools.cmake
@ -0,0 +1,41 @@
+if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
+    set (COMPILER_GCC 1)
+elseif (CMAKE_CXX_COMPILER_ID MATCHES "Clang|AppleClang")
+    set (COMPILER_CLANG 1)
+endif ()
+
+if (COMPILER_GCC)
+    # Require minimum version of gcc
+    set (GCC_MINIMUM_VERSION 8)
+    if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS ${GCC_MINIMUM_VERSION} AND NOT CMAKE_VERSION VERSION_LESS 2.8.9)
+        message (FATAL_ERROR "GCC version must be at least ${GCC_MINIMUM_VERSION}. For example, if GCC ${GCC_MINIMUM_VERSION} is available under gcc-${GCC_MINIMUM_VERSION}, g++-${GCC_MINIMUM_VERSION} names, do the following: export CC=gcc-${GCC_MINIMUM_VERSION} CXX=g++-${GCC_MINIMUM_VERSION}; rm -rf CMakeCache.txt CMakeFiles; and re run cmake or ./release.")
+    endif ()
+elseif (COMPILER_CLANG)
+    # Require minimum version of clang
+    set (CLANG_MINIMUM_VERSION 7)
+    if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS ${CLANG_MINIMUM_VERSION})
+        message (FATAL_ERROR "Clang version must be at least ${CLANG_MINIMUM_VERSION}.")
+    endif ()
+else ()
+    message (WARNING "You are using an unsupported compiler. Compilation has only been tested with Clang 6+ and GCC 7+.")
+endif ()
+
+option (LINKER_NAME "Linker name or full path")
+
+find_program (LLD_PATH NAMES "ld.lld" "lld")
+find_program (GOLD_PATH NAMES "ld.gold" "gold")
+
+if (NOT LINKER_NAME)
+    if (LLD_PATH)
+        set (LINKER_NAME "lld")
+    elseif (GOLD_PATH)
+        set (LINKER_NAME "gold")
+    endif ()
+endif ()
+
+if (LINKER_NAME)
+    set (CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -fuse-ld=${LINKER_NAME}")
+    set (CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -fuse-ld=${LINKER_NAME}")
+
+    message(STATUS "Using custom linker by name: ${LINKER_NAME}")
+endif ()
--- a/contrib/CMakeLists.txt
+++ b/contrib/CMakeLists.txt
@ -124,7 +124,7 @@ if (USE_INTERNAL_SSL_LIBRARY)
    add_library(OpenSSL::SSL ALIAS ${OPENSSL_SSL_LIBRARY})
 endif ()

-if (ENABLE_MYSQL AND USE_INTERNAL_MYSQL_LIBRARY)
+function(mysql_support)
    set(CLIENT_PLUGIN_CACHING_SHA2_PASSWORD STATIC)
    set(CLIENT_PLUGIN_SHA256_PASSWORD STATIC)
    set(CLIENT_PLUGIN_REMOTE_IO OFF)
@ -136,7 +136,15 @@ if (ENABLE_MYSQL AND USE_INTERNAL_MYSQL_LIBRARY)
    if (GLIBC_COMPATIBILITY)
        set(LIBM glibc-compatibility)
    endif()
+    if (USE_INTERNAL_ZLIB_LIBRARY)
+        set(ZLIB_FOUND ON)
+        set(ZLIB_LIBRARY zlibstatic)
+        set(WITH_EXTERNAL_ZLIB ON)
+    endif()
    add_subdirectory (mariadb-connector-c)
+endfunction()
+if (ENABLE_MYSQL AND USE_INTERNAL_MYSQL_LIBRARY)
+    mysql_support()
 endif ()

 if (USE_INTERNAL_RDKAFKA_LIBRARY)
--- a/contrib/arrow-cmake/CMakeLists.txt
+++ b/contrib/arrow-cmake/CMakeLists.txt
@ -70,6 +70,14 @@ add_custom_command(OUTPUT orc_proto.pb.h orc_proto.pb.cc
        --cpp_out="${CMAKE_CURRENT_BINARY_DIR}"
        "${PROTO_DIR}/orc_proto.proto")

+# arrow-cmake cmake file calling orc cmake subroutine which detects certain compiler features. 
+# Apple Clang compiler failed to compile this code without specifying c++11 standard. 
+# As result these compiler features detected as absent. In result it failed to compile orc itself.
+# In orc makefile there is code that sets flags, but arrow-cmake ignores these flags.
+if (CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang")
+  set (CXX11_FLAGS "-std=c++0x")
+endif()
+
 include(${ClickHouse_SOURCE_DIR}/contrib/orc/cmake_modules/CheckSourceCompiles.cmake)
 include(orc_check.cmake)
 configure_file("${ORC_INCLUDE_DIR}/orc/orc-config.hh.in"  "${ORC_BUILD_INCLUDE_DIR}/orc/orc-config.hh")
--- a/contrib/libcxx-cmake/CMakeLists.txt
+++ b/contrib/libcxx-cmake/CMakeLists.txt
@ -44,7 +44,7 @@ target_include_directories(cxx SYSTEM BEFORE PUBLIC $<BUILD_INTERFACE:${LIBCXX_S
 target_compile_definitions(cxx PRIVATE -D_LIBCPP_BUILDING_LIBRARY -DLIBCXX_BUILDING_LIBCXXABI)

 target_compile_options(cxx PUBLIC -nostdinc++ -Wno-reserved-id-macro)
-if (OS_DARWIN AND NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 9)
+if (OS_DARWIN AND (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 9) AND (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 11))
    target_compile_options(cxx PUBLIC -Wno-ctad-maybe-unsupported)
 endif ()

--- a/dbms/CMakeLists.txt
+++ b/dbms/CMakeLists.txt
@ -130,8 +130,8 @@ list (APPEND dbms_headers

 list (APPEND dbms_sources src/TableFunctions/ITableFunction.cpp src/TableFunctions/TableFunctionFactory.cpp)
 list (APPEND dbms_headers src/TableFunctions/ITableFunction.h   src/TableFunctions/TableFunctionFactory.h)
-list (APPEND dbms_sources src/Dictionaries/DictionaryFactory.cpp src/Dictionaries/DictionarySourceFactory.cpp src/Dictionaries/DictionaryStructure.cpp)
-list (APPEND dbms_headers src/Dictionaries/DictionaryFactory.h   src/Dictionaries/DictionarySourceFactory.h   src/Dictionaries/DictionaryStructure.h)
+list (APPEND dbms_sources src/Dictionaries/DictionaryFactory.cpp src/Dictionaries/DictionarySourceFactory.cpp src/Dictionaries/DictionaryStructure.cpp  src/Dictionaries/getDictionaryConfigurationFromAST.cpp)
+list (APPEND dbms_headers src/Dictionaries/DictionaryFactory.h   src/Dictionaries/DictionarySourceFactory.h   src/Dictionaries/DictionaryStructure.h src/Dictionaries/getDictionaryConfigurationFromAST.h)

 if (NOT ENABLE_SSL)
    list (REMOVE_ITEM clickhouse_common_io_sources src/Common/OpenSSLHelpers.cpp)
@ -153,12 +153,10 @@ add_subdirectory(src/Common/Config)
 set (all_modules)
 macro(add_object_library name common_path)
    if (MAKE_STATIC_LIBRARIES OR NOT SPLIT_SHARED_LIBRARIES)
-        add_glob(dbms_headers RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} ${common_path}/*.h)
-        add_glob(dbms_sources ${common_path}/*.cpp ${common_path}/*.c ${common_path}/*.h)
+        add_headers_and_sources(dbms ${common_path})
    else ()
        list (APPEND all_modules ${name})
-        add_glob(${name}_headers RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} ${common_path}/*.h)
-        add_glob(${name}_sources ${common_path}/*.cpp ${common_path}/*.c ${common_path}/*.h)
+        add_headers_and_sources(${name} ${common_path})
        add_library(${name} SHARED ${${name}_sources} ${${name}_headers})
        target_link_libraries (${name} PRIVATE -Wl,--unresolved-symbols=ignore-all)
    endif ()
@ -427,6 +425,11 @@ endif()
 if (USE_JEMALLOC)
    dbms_target_include_directories (SYSTEM BEFORE PRIVATE ${JEMALLOC_INCLUDE_DIR}) # used in Interpreters/AsynchronousMetrics.cpp
    target_include_directories (clickhouse_new_delete SYSTEM BEFORE PRIVATE ${JEMALLOC_INCLUDE_DIR})
+
+    if(NOT MAKE_STATIC_LIBRARIES AND ${JEMALLOC_LIBRARIES} MATCHES "${CMAKE_STATIC_LIBRARY_SUFFIX}$")
+        # mallctl in dbms/src/Interpreters/AsynchronousMetrics.cpp
+        target_link_libraries(clickhouse_interpreters PRIVATE ${JEMALLOC_LIBRARIES})
+    endif()
 endif ()

 dbms_target_include_directories (PUBLIC ${DBMS_INCLUDE_DIR} PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src/Formats/include)
--- a/dbms/programs/benchmark/Benchmark.cpp
+++ b/dbms/programs/benchmark/Benchmark.cpp
@ -365,7 +365,7 @@ private:
        Stopwatch watch;
        RemoteBlockInputStream stream(
            *(*connection_entries[connection_index]),
-            query, {}, global_context, &settings, nullptr, Tables(), query_processing_stage);
+            query, {}, global_context, &settings, nullptr, Scalars(), Tables(), query_processing_stage);

        Progress progress;
        stream.setProgressCallback([&progress](const Progress & value) { progress.incrementPiecewiseAtomically(value); });
--- a/dbms/programs/client/Client.cpp
+++ b/dbms/programs/client/Client.cpp
@ -89,6 +89,40 @@
 #define DISABLE_LINE_WRAPPING "\033[?7l"
 #define ENABLE_LINE_WRAPPING "\033[?7h"

+#if USE_READLINE && RL_VERSION_MAJOR >= 7
+
+#define BRACK_PASTE_PREF "\033[200~"
+#define BRACK_PASTE_SUFF "\033[201~"
+
+#define BRACK_PASTE_LAST '~'
+#define BRACK_PASTE_SLEN 6
+
+/// Make sure we don't get ^J for the enter character.
+/// This handler also bypasses some unused macro/event checkings.
+static int clickhouse_rl_bracketed_paste_begin(int /* count */, int /* key */)
+{
+    std::string buf;
+    buf.reserve(128);
+
+    RL_SETSTATE(RL_STATE_MOREINPUT);
+    SCOPE_EXIT(RL_UNSETSTATE(RL_STATE_MOREINPUT));
+    char c;
+    while ((c = rl_read_key()) >= 0)
+    {
+        if (c == '\r' || c == '\n')
+            c = '\n';
+        buf.push_back(c);
+        if (buf.size() >= BRACK_PASTE_SLEN && c == BRACK_PASTE_LAST && buf.substr(buf.size() - BRACK_PASTE_SLEN) == BRACK_PASTE_SUFF)
+        {
+            buf.resize(buf.size() - BRACK_PASTE_SLEN);
+            break;
+        }
+    }
+    return static_cast<size_t>(rl_insert_text(buf.c_str())) == buf.size() ? 0 : 1;
+}
+
+#endif
+
 namespace DB
 {

@ -462,6 +496,18 @@ private:
            if (rl_initialize())
                throw Exception("Cannot initialize readline", ErrorCodes::CANNOT_READLINE);

+#if RL_VERSION_MAJOR >= 7
+            /// When bracketed paste mode is set, pasted text is bracketed with control sequences so
+            ///  that the program can differentiate pasted text from typed-in text. This helps
+            ///  clickhouse-client so that without -m flag, one can still paste multiline queries, and
+            ///  possibly get better pasting performance. See https://cirw.in/blog/bracketed-paste for
+            ///  more details.
+            rl_variable_bind("enable-bracketed-paste", "on");
+
+            /// Use our bracketed paste handler to get better user experience. See comments above.
+            rl_bind_keyseq(BRACK_PASTE_PREF, clickhouse_rl_bracketed_paste_begin);
+#endif
+
            auto clear_prompt_or_exit = [](int)
            {
                /// This is signal safe.
@ -632,7 +678,8 @@ private:
                    /// If the user restarts the client then after pressing the "up" button
                    /// every line of the query will be displayed separately.
                    std::string logged_query = input;
-                    std::replace(logged_query.begin(), logged_query.end(), '\n', ' ');
+                    if (config().has("multiline"))
+                        std::replace(logged_query.begin(), logged_query.end(), '\n', ' ');
                    add_history(logged_query.c_str());

 #if USE_READLINE && HAVE_READLINE_HISTORY
--- a/dbms/programs/obfuscator/Obfuscator.cpp
+++ b/dbms/programs/obfuscator/Obfuscator.cpp
@ -579,7 +579,7 @@ public:
        {
            for (auto & elem : table)
            {
-                Histogram & histogram = elem.getSecond();
+                Histogram & histogram = elem.getMapped();

                if (histogram.buckets.size() < params.num_buckets_cutoff)
                {
@ -593,7 +593,7 @@ public:
        {
            for (auto & elem : table)
            {
-                Histogram & histogram = elem.getSecond();
+                Histogram & histogram = elem.getMapped();
                if (!histogram.total)
                    continue;

@ -625,7 +625,7 @@ public:
        {
            for (auto & elem : table)
            {
-                Histogram & histogram = elem.getSecond();
+                Histogram & histogram = elem.getMapped();
                if (!histogram.total)
                    continue;

@ -641,7 +641,7 @@ public:
        {
            for (auto & elem : table)
            {
-                Histogram & histogram = elem.getSecond();
+                Histogram & histogram = elem.getMapped();
                if (!histogram.total)
                    continue;

@ -676,7 +676,7 @@ public:
            while (true)
            {
                it = table.find(hashContext(code_points.data() + code_points.size() - context_size, code_points.data() + code_points.size()));
-                if (it && lookupResultGetMapped(it)->total + lookupResultGetMapped(it)->count_end != 0)
+                if (it && it->getMapped().total + it->getMapped().count_end != 0)
                    break;

                if (context_size == 0)
@ -710,7 +710,7 @@ public:
            if (num_bytes_after_desired_size > 0)
                end_probability_multiplier = std::pow(1.25, num_bytes_after_desired_size);

-            CodePoint code = lookupResultGetMapped(it)->sample(determinator, end_probability_multiplier);
+            CodePoint code = it->getMapped().sample(determinator, end_probability_multiplier);

            if (code == END)
                break;
--- a/dbms/programs/odbc-bridge/ColumnInfoHandler.cpp
+++ b/dbms/programs/odbc-bridge/ColumnInfoHandler.cpp
@ -38,12 +38,16 @@ namespace

        switch (type)
        {
+            case SQL_TINYINT:
+                return factory.get("Int8");
            case SQL_INTEGER:
                return factory.get("Int32");
            case SQL_SMALLINT:
                return factory.get("Int16");
+            case SQL_BIGINT:
+                return factory.get("Int64");
            case SQL_FLOAT:
-                return factory.get("Float32");
+                return factory.get("Float64");
            case SQL_REAL:
                return factory.get("Float32");
            case SQL_DOUBLE:
--- a/dbms/programs/performance-test/JSONString.h
+++ b/dbms/programs/performance-test/JSONString.h
@ -22,7 +22,7 @@ public:
    void set(const std::string & key, std::string value, bool wrap = true);

    template <typename T>
-    std::enable_if_t<std::is_arithmetic_v<T>> set(const std::string key, T value)
+    std::enable_if_t<is_arithmetic_v<T>> set(const std::string key, T value)
    {
        set(key, std::to_string(value), /*wrap= */ false);
    }
--- a/dbms/programs/server/CMakeLists.txt
+++ b/dbms/programs/server/CMakeLists.txt
@ -10,13 +10,11 @@ set(CLICKHOUSE_SERVER_SOURCES
    ${CMAKE_CURRENT_SOURCE_DIR}/TCPHandler.cpp
   )

-if (USE_SSL)
-    set(CLICKHOUSE_SERVER_SOURCES
-        ${CLICKHOUSE_SERVER_SOURCES}
-        ${CMAKE_CURRENT_SOURCE_DIR}/MySQLHandler.cpp
-        ${CMAKE_CURRENT_SOURCE_DIR}/MySQLHandlerFactory.cpp
-    )
-endif ()
+set(CLICKHOUSE_SERVER_SOURCES
+    ${CLICKHOUSE_SERVER_SOURCES}
+    ${CMAKE_CURRENT_SOURCE_DIR}/MySQLHandler.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/MySQLHandlerFactory.cpp
+)

 set(CLICKHOUSE_SERVER_LINK PRIVATE clickhouse_dictionaries clickhouse_common_io clickhouse_common_config clickhouse_common_zookeeper clickhouse_parsers string_utils PUBLIC daemon PRIVATE clickhouse_storages_system clickhouse_functions clickhouse_aggregate_functions clickhouse_table_functions ${Poco_Net_LIBRARY})
 if (USE_POCO_NETSSL)
--- a/dbms/programs/server/MySQLHandler.cpp
+++ b/dbms/programs/server/MySQLHandler.cpp
@ -1,7 +1,6 @@
 #include <Common/config.h>
-#if USE_SSL
-#include "MySQLHandler.h"

+#include "MySQLHandler.h"
 #include <limits>
 #include <ext/scope_guard.h>
 #include <Columns/ColumnVector.h>
@ -15,37 +14,39 @@
 #include <IO/ReadBufferFromPocoSocket.h>
 #include <IO/ReadBufferFromString.h>
 #include <IO/WriteBufferFromPocoSocket.h>
-#include <Poco/Crypto/CipherFactory.h>
-#include <Poco/Crypto/RSAKey.h>
-#include <Poco/Net/SecureStreamSocket.h>
-#include <Poco/Net/SSLManager.h>
 #include <Storages/IStorage.h>

+#if USE_POCO_NETSSL
+#include <Poco/Net/SecureStreamSocket.h>
+#include <Poco/Net/SSLManager.h>
+#include <Poco/Crypto/CipherFactory.h>
+#include <Poco/Crypto/RSAKey.h>
+#endif

 namespace DB
 {

 using namespace MySQLProtocol;

-
+#if USE_POCO_NETSSL
 using Poco::Net::SecureStreamSocket;
 using Poco::Net::SSLManager;
-
+#endif

 namespace ErrorCodes
 {
    extern const int MYSQL_CLIENT_INSUFFICIENT_CAPABILITIES;
    extern const int OPENSSL_ERROR;
+    extern const int SUPPORT_IS_DISABLED;
 }

-MySQLHandler::MySQLHandler(IServer & server_, const Poco::Net::StreamSocket & socket_, RSA & public_key_, RSA & private_key_, bool ssl_enabled, size_t connection_id_)
+MySQLHandler::MySQLHandler(IServer & server_, const Poco::Net::StreamSocket & socket_,
+    bool ssl_enabled, size_t connection_id_)
    : Poco::Net::TCPServerConnection(socket_)
    , server(server_)
    , log(&Poco::Logger::get("MySQLHandler"))
    , connection_context(server.context())
    , connection_id(connection_id_)
-    , public_key(public_key_)
-    , private_key(private_key_)
    , auth_plugin(new MySQLProtocol::Authentication::Native41())
 {
    server_capability_flags = CLIENT_PROTOCOL_41 | CLIENT_SECURE_CONNECTION | CLIENT_PLUGIN_AUTH | CLIENT_PLUGIN_AUTH_LENENC_CLIENT_DATA | CLIENT_CONNECT_WITH_DB | CLIENT_DEPRECATE_EOF;
@ -197,21 +198,7 @@ void MySQLHandler::finishHandshake(MySQLProtocol::HandshakeResponse & packet)

    if (payload_size == SSL_REQUEST_PAYLOAD_SIZE)
    {
-        read_bytes(packet_size); /// Reading rest SSLRequest.
-        SSLRequest ssl_request;
-        ReadBufferFromMemory payload(buf, pos);
-        payload.ignore(PACKET_HEADER_SIZE);
-        ssl_request.readPayload(payload);
-        connection_context.mysql.client_capabilities = ssl_request.capability_flags;
-        connection_context.mysql.max_packet_size = ssl_request.max_packet_size ? ssl_request.max_packet_size : MAX_PACKET_LENGTH;
-        secure_connection = true;
-        ss = std::make_shared<SecureStreamSocket>(SecureStreamSocket::attach(socket(), SSLManager::instance().defaultServerContext()));
-        in = std::make_shared<ReadBufferFromPocoSocket>(*ss);
-        out = std::make_shared<WriteBufferFromPocoSocket>(*ss);
-        connection_context.mysql.sequence_id = 2;
-        packet_sender = std::make_shared<PacketSender>(*in, *out, connection_context.mysql.sequence_id);
-        packet_sender->max_packet_size = connection_context.mysql.max_packet_size;
-        packet_sender->receivePacket(packet); /// Reading HandshakeResponse from secure socket.
+        finishHandshakeSSL(packet_size, buf, pos, read_bytes, packet);
    }
    else
    {
@ -232,7 +219,9 @@ void MySQLHandler::authenticate(const String & user_name, const String & auth_pl
    // For compatibility with JavaScript MySQL client, Native41 authentication plugin is used when possible (if password is specified using double SHA1). Otherwise SHA256 plugin is used.
    auto user = connection_context.getUser(user_name);
    if (user->authentication.getType() != DB::Authentication::DOUBLE_SHA1_PASSWORD)
-        auth_plugin = std::make_unique<MySQLProtocol::Authentication::Sha256Password>(public_key, private_key, log);
+    {
+        authPluginSSL();
+    }

    try {
        std::optional<String> auth_response = auth_plugin_name == auth_plugin->getName() ? std::make_optional<String>(initial_auth_response) : std::nullopt;
@ -302,5 +291,47 @@ void MySQLHandler::comQuery(ReadBuffer & payload)
        packet_sender->sendPacket(OK_Packet(0x00, client_capability_flags, 0, 0, 0), true);
 }

+void MySQLHandler::authPluginSSL()
+{
+    throw Exception("Compiled without SSL", ErrorCodes::SUPPORT_IS_DISABLED);
 }
+
+void MySQLHandler::finishHandshakeSSL([[maybe_unused]] size_t packet_size, [[maybe_unused]] char * buf, [[maybe_unused]] size_t pos, [[maybe_unused]] std::function<void(size_t)> read_bytes, [[maybe_unused]] MySQLProtocol::HandshakeResponse & packet)
+{
+    throw Exception("Compiled without SSL", ErrorCodes::SUPPORT_IS_DISABLED);
+}
+
+#if USE_SSL && USE_POCO_NETSSL
+MySQLHandlerSSL::MySQLHandlerSSL(IServer & server_, const Poco::Net::StreamSocket & socket_, bool ssl_enabled, size_t connection_id_, RSA & public_key_, RSA & private_key_)
+    : MySQLHandler(server_, socket_, ssl_enabled, connection_id_)
+    , public_key(public_key_)
+    , private_key(private_key_)
+{}
+
+void MySQLHandlerSSL::authPluginSSL()
+{
+    auth_plugin = std::make_unique<MySQLProtocol::Authentication::Sha256Password>(public_key, private_key, log);
+}
+
+void MySQLHandlerSSL::finishHandshakeSSL(size_t packet_size, char * buf, size_t pos, std::function<void(size_t)> read_bytes, MySQLProtocol::HandshakeResponse & packet)
+{
+    read_bytes(packet_size); /// Reading rest SSLRequest.
+    SSLRequest ssl_request;
+    ReadBufferFromMemory payload(buf, pos);
+    payload.ignore(PACKET_HEADER_SIZE);
+    ssl_request.readPayload(payload);
+    connection_context.mysql.client_capabilities = ssl_request.capability_flags;
+    connection_context.mysql.max_packet_size = ssl_request.max_packet_size ? ssl_request.max_packet_size : MAX_PACKET_LENGTH;
+    secure_connection = true;
+    ss = std::make_shared<SecureStreamSocket>(SecureStreamSocket::attach(socket(), SSLManager::instance().defaultServerContext()));
+    in = std::make_shared<ReadBufferFromPocoSocket>(*ss);
+    out = std::make_shared<WriteBufferFromPocoSocket>(*ss);
+    connection_context.mysql.sequence_id = 2;
+    packet_sender = std::make_shared<PacketSender>(*in, *out, connection_context.mysql.sequence_id);
+    packet_sender->max_packet_size = connection_context.mysql.max_packet_size;
+    packet_sender->receivePacket(packet); /// Reading HandshakeResponse from secure socket.
+}
+
 #endif
+
+}
--- a/dbms/programs/server/MySQLHandler.h
+++ b/dbms/programs/server/MySQLHandler.h
@ -1,13 +1,13 @@
 #pragma once
 #include <Common/config.h>
-#if USE_SSL
-
 #include <Poco/Net/TCPServerConnection.h>
-#include <Poco/Net/SecureStreamSocket.h>
 #include <Common/getFQDNOrHostName.h>
 #include <Core/MySQLProtocol.h>
 #include "IServer.h"

+#if USE_POCO_NETSSL
+#include <Poco/Net/SecureStreamSocket.h>
+#endif

 namespace DB
 {
@ -16,7 +16,7 @@ namespace DB
 class MySQLHandler : public Poco::Net::TCPServerConnection
 {
 public:
-    MySQLHandler(IServer & server_, const Poco::Net::StreamSocket & socket_, RSA & public_key_, RSA & private_key_, bool ssl_enabled, size_t connection_id_);
+    MySQLHandler(IServer & server_, const Poco::Net::StreamSocket & socket_, bool ssl_enabled, size_t connection_id_);

    void run() final;

@ -34,28 +34,47 @@ private:

    void authenticate(const String & user_name, const String & auth_plugin_name, const String & auth_response);

+    virtual void authPluginSSL();
+    virtual void finishHandshakeSSL(size_t packet_size, char * buf, size_t pos, std::function<void(size_t)> read_bytes, MySQLProtocol::HandshakeResponse & packet);
+
    IServer & server;
+
+protected:
    Poco::Logger * log;
+
    Context connection_context;

    std::shared_ptr<MySQLProtocol::PacketSender> packet_sender;

+private:
    size_t connection_id = 0;

    size_t server_capability_flags = 0;
    size_t client_capability_flags = 0;

-    RSA & public_key;
-    RSA & private_key;
-
+protected:
    std::unique_ptr<MySQLProtocol::Authentication::IPlugin> auth_plugin;

-    std::shared_ptr<Poco::Net::SecureStreamSocket> ss;
    std::shared_ptr<ReadBuffer> in;
    std::shared_ptr<WriteBuffer> out;

    bool secure_connection = false;
 };

-}
+#if USE_SSL && USE_POCO_NETSSL
+class MySQLHandlerSSL : public MySQLHandler
+{
+public:
+    MySQLHandlerSSL(IServer & server_, const Poco::Net::StreamSocket & socket_, bool ssl_enabled, size_t connection_id_, RSA & public_key_, RSA & private_key_);
+
+private:
+    void authPluginSSL() override;
+    void finishHandshakeSSL(size_t packet_size, char * buf, size_t pos, std::function<void(size_t)> read_bytes, MySQLProtocol::HandshakeResponse & packet) override;
+
+    RSA & public_key;
+    RSA & private_key;
+    std::shared_ptr<Poco::Net::SecureStreamSocket> ss;
+};
 #endif
+
+}
--- a/dbms/programs/server/MySQLHandlerFactory.cpp
+++ b/dbms/programs/server/MySQLHandlerFactory.cpp
@ -1,7 +1,5 @@
 #include "MySQLHandlerFactory.h"
-#if USE_POCO_NETSSL && USE_SSL
 #include <Common/OpenSSLHelpers.h>
-#include <Poco/Net/SSLManager.h>
 #include <Poco/Net/TCPServerConnectionFactory.h>
 #include <Poco/Util/Application.h>
 #include <common/logger_useful.h>
@ -9,6 +7,10 @@
 #include "IServer.h"
 #include "MySQLHandler.h"

+#if USE_POCO_NETSSL
+#include <Poco/Net/SSLManager.h>
+#endif
+
 namespace DB
 {

@ -24,6 +26,8 @@ MySQLHandlerFactory::MySQLHandlerFactory(IServer & server_)
    : server(server_)
    , log(&Logger::get("MySQLHandlerFactory"))
 {
+
+#if USE_POCO_NETSSL
    try
    {
        Poco::Net::SSLManager::instance().defaultServerContext();
@ -33,7 +37,9 @@ MySQLHandlerFactory::MySQLHandlerFactory(IServer & server_)
        LOG_INFO(log, "Failed to create SSL context. SSL will be disabled. Error: " << getCurrentExceptionMessage(false));
        ssl_enabled = false;
    }
+#endif

+#if USE_SSL
    /// Reading rsa keys for SHA256 authentication plugin.
    try
    {
@ -44,8 +50,10 @@ MySQLHandlerFactory::MySQLHandlerFactory(IServer & server_)
        LOG_WARNING(log, "Failed to read RSA keys. Error: " << getCurrentExceptionMessage(false));
        generateRSAKeys();
    }
+#endif
 }

+#if USE_SSL
 void MySQLHandlerFactory::readRSAKeys()
 {
    const Poco::Util::LayeredConfiguration & config = Poco::Util::Application::instance().config();
@ -113,13 +121,18 @@ void MySQLHandlerFactory::generateRSAKeys()
    if (!private_key)
        throw Exception("Failed to copy RSA key. Error: " + getOpenSSLErrors(), ErrorCodes::OPENSSL_ERROR);
 }
+#endif

 Poco::Net::TCPServerConnection * MySQLHandlerFactory::createConnection(const Poco::Net::StreamSocket & socket)
 {
    size_t connection_id = last_connection_id++;
    LOG_TRACE(log, "MySQL connection. Id: " << connection_id << ". Address: " << socket.peerAddress().toString());
-    return new MySQLHandler(server, socket, *public_key, *private_key, ssl_enabled, connection_id);
+#if USE_POCO_NETSSL && USE_SSL
+    return new MySQLHandlerSSL(server, socket, ssl_enabled, connection_id, *public_key, *private_key);
+#else
+    return new MySQLHandler(server, socket, ssl_enabled, connection_id);
+#endif
+
 }

 }
-#endif
--- a/dbms/programs/server/MySQLHandlerFactory.h
+++ b/dbms/programs/server/MySQLHandlerFactory.h
@ -1,12 +1,12 @@
 #pragma once

 #include <Common/config.h>
-#if USE_POCO_NETSSL && USE_SSL
-
 #include <Poco/Net/TCPServerConnectionFactory.h>
 #include <atomic>
-#include <openssl/rsa.h>
 #include "IServer.h"
+#if USE_SSL
+#include <openssl/rsa.h>
+#endif

 namespace DB
 {
@ -17,6 +17,7 @@ private:
    IServer & server;
    Poco::Logger * log;

+#if USE_SSL
    struct RSADeleter
    {
        void operator()(RSA * ptr) { RSA_free(ptr); }
@ -27,6 +28,9 @@ private:
    RSAPtr private_key;

    bool ssl_enabled = true;
+#else
+    bool ssl_enabled = false;
+#endif

    std::atomic<size_t> last_connection_id = 0;
 public:
@ -40,4 +44,3 @@ public:
 };

 }
-#endif
--- a/dbms/programs/server/ReplicasStatusHandler.cpp
+++ b/dbms/programs/server/ReplicasStatusHandler.cpp
@ -44,7 +44,7 @@ void ReplicasStatusHandler::handleRequest(Poco::Net::HTTPServerRequest & request
            if (db.second->getEngineName() == "Lazy")
                continue;

-            for (auto iterator = db.second->getIterator(context); iterator->isValid(); iterator->next())
+            for (auto iterator = db.second->getTablesIterator(context); iterator->isValid(); iterator->next())
            {
                auto & table = iterator->table();
                StorageReplicatedMergeTree * table_replicated = dynamic_cast<StorageReplicatedMergeTree *>(table.get());
--- a/dbms/programs/server/Server.cpp
+++ b/dbms/programs/server/Server.cpp
@ -37,10 +37,12 @@
 #include <Interpreters/AsynchronousMetrics.h>
 #include <Interpreters/DDLWorker.h>
 #include <Interpreters/ExternalDictionariesLoader.h>
+#include <Interpreters/ExternalModelsLoader.h>
 #include <Interpreters/ProcessList.h>
 #include <Interpreters/loadMetadata.h>
 #include <Interpreters/DNSCacheUpdater.h>
 #include <Interpreters/SystemLog.cpp>
+#include <Interpreters/ExternalLoaderXMLConfigRepository.h>
 #include <Storages/StorageReplicatedMergeTree.h>
 #include <Storages/System/attachSystemTables.h>
 #include <AggregateFunctions/registerAggregateFunctions.h>
@ -55,7 +57,7 @@
 #include "TCPHandlerFactory.h"
 #include "Common/config_version.h"
 #include <Common/SensitiveDataMasker.h>
-
+#include "MySQLHandlerFactory.h"

 #if defined(OS_LINUX)
 #include <Common/hasLinuxCapability.h>
@ -63,7 +65,6 @@
 #endif

 #if USE_POCO_NETSSL
-#include "MySQLHandlerFactory.h"
 #include <Poco/Net/Context.h>
 #include <Poco/Net/SecureServerSocket.h>
 #endif
@ -920,6 +921,12 @@ int Server::main(const std::vector<std::string> & /*args*/)
                global_context->tryCreateEmbeddedDictionaries();
                global_context->getExternalDictionariesLoader().enableAlwaysLoadEverything(true);
            }
+
+            auto dictionaries_repository = std::make_unique<ExternalLoaderXMLConfigRepository>(config(), "dictionaries_config");
+            global_context->getExternalDictionariesLoader().addConfigRepository("", std::move(dictionaries_repository));
+
+            auto models_repository = std::make_unique<ExternalLoaderXMLConfigRepository>(config(), "models_config");
+            global_context->getExternalModelsLoader().addConfigRepository("", std::move(models_repository));
        }
        catch (...)
        {
--- a/dbms/programs/server/TCPHandler.cpp
+++ b/dbms/programs/server/TCPHandler.cpp
@ -530,7 +530,8 @@ void TCPHandler::processOrdinaryQuery()
                sendLogs();
            }

-            sendData(block);
+            if (!block || !state.io.null_format)
+                sendData(block);
            if (!block)
                break;
        }
@ -850,9 +851,10 @@ bool TCPHandler::receivePacket()
            return true;

        case Protocol::Client::Data:
+        case Protocol::Client::Scalar:
            if (state.empty())
                receiveUnexpectedData();
-            return receiveData();
+            return receiveData(packet_type == Protocol::Client::Scalar);

        case Protocol::Client::Ping:
            writeVarUInt(Protocol::Server::Pong, *out);
@ -957,39 +959,44 @@ void TCPHandler::receiveUnexpectedQuery()
    throw NetException("Unexpected packet Query received from client", ErrorCodes::UNEXPECTED_PACKET_FROM_CLIENT);
 }

-bool TCPHandler::receiveData()
+bool TCPHandler::receiveData(bool scalar)
 {
    initBlockInput();

    /// The name of the temporary table for writing data, default to empty string
-    String external_table_name;
-    readStringBinary(external_table_name, *in);
+    String name;
+    readStringBinary(name, *in);

    /// Read one block from the network and write it down
    Block block = state.block_in->read();

    if (block)
    {
-        /// If there is an insert request, then the data should be written directly to `state.io.out`.
-        /// Otherwise, we write the blocks in the temporary `external_table_name` table.
-        if (!state.need_receive_data_for_insert && !state.need_receive_data_for_input)
-        {
-            StoragePtr storage;
-            /// If such a table does not exist, create it.
-            if (!(storage = query_context->tryGetExternalTable(external_table_name)))
-            {
-                NamesAndTypesList columns = block.getNamesAndTypesList();
-                storage = StorageMemory::create("_external", external_table_name, ColumnsDescription{columns}, ConstraintsDescription{});
-                storage->startup();
-                query_context->addExternalTable(external_table_name, storage);
-            }
-            /// The data will be written directly to the table.
-            state.io.out = storage->write(ASTPtr(), *query_context);
-        }
-        if (state.need_receive_data_for_input)
-            state.block_for_input = block;
+        if (scalar)
+            query_context->addScalar(name, block);
        else
-            state.io.out->write(block);
+        {
+            /// If there is an insert request, then the data should be written directly to `state.io.out`.
+            /// Otherwise, we write the blocks in the temporary `external_table_name` table.
+            if (!state.need_receive_data_for_insert && !state.need_receive_data_for_input)
+            {
+                StoragePtr storage;
+                /// If such a table does not exist, create it.
+                if (!(storage = query_context->tryGetExternalTable(name)))
+                {
+                    NamesAndTypesList columns = block.getNamesAndTypesList();
+                    storage = StorageMemory::create("_external", name, ColumnsDescription{columns}, ConstraintsDescription{});
+                    storage->startup();
+                    query_context->addExternalTable(name, storage);
+                }
+                /// The data will be written directly to the table.
+                state.io.out = storage->write(ASTPtr(), *query_context);
+            }
+            if (state.need_receive_data_for_input)
+                state.block_for_input = block;
+            else
+                state.io.out->write(block);
+        }
        return true;
    }
    else
--- a/dbms/programs/server/TCPHandler.h
+++ b/dbms/programs/server/TCPHandler.h
@ -153,7 +153,7 @@ private:
    void receiveHello();
    bool receivePacket();
    void receiveQuery();
-    bool receiveData();
+    bool receiveData(bool scalar);
    bool readDataNext(const size_t & poll_interval, const int & receive_timeout);
    void readData(const Settings & global_settings);
    std::tuple<size_t, int> getReadTimeouts(const Settings & global_settings);
--- a/dbms/programs/server/config.xml
+++ b/dbms/programs/server/config.xml
@ -180,7 +180,21 @@
                     <port>9000</port>
                 </replica>
             </shard>
-         </test_cluster_two_shards_localhost>
+        </test_cluster_two_shards_localhost>
+        <test_cluster_two_shards>
+            <shard>
+                <replica>
+                    <host>127.0.0.1</host>
+                    <port>9000</port>
+                </replica>
+            </shard>
+            <shard>
+                <replica>
+                    <host>127.0.0.2</host>
+                    <port>9000</port>
+                </replica>
+            </shard>
+        </test_cluster_two_shards>
        <test_shard_localhost_secure>
            <shard>
                <replica>
--- a/dbms/src/Interpreters/SettingsConstraints.cpp
+++ b/dbms/src/Interpreters/SettingsConstraints.cpp
@ -1,4 +1,4 @@
-#include <Interpreters/SettingsConstraints.h>
+#include <Access/SettingsConstraints.h>
 #include <Core/Settings.h>
 #include <Common/FieldVisitors.h>
 #include <IO/WriteHelpers.h>
@ -29,22 +29,118 @@ void SettingsConstraints::clear()
 }


-void SettingsConstraints::setReadOnly(const String & name, bool read_only)
+void SettingsConstraints::setMinValue(const StringRef & name, const Field & min_value)
+{
+    size_t setting_index = Settings::findIndexStrict(name);
+    getConstraintRef(setting_index).min_value = Settings::valueToCorrespondingType(setting_index, min_value);
+}
+
+
+Field SettingsConstraints::getMinValue(const StringRef & name) const
+{
+    size_t setting_index = Settings::findIndexStrict(name);
+    const auto * ptr = tryGetConstraint(setting_index);
+    if (ptr)
+        return ptr->min_value;
+    else
+        return {};
+}
+
+
+void SettingsConstraints::setMaxValue(const StringRef & name, const Field & max_value)
+{
+    size_t setting_index = Settings::findIndexStrict(name);
+    getConstraintRef(setting_index).max_value = Settings::valueToCorrespondingType(setting_index, max_value);
+}
+
+
+Field SettingsConstraints::getMaxValue(const StringRef & name) const
+{
+    size_t setting_index = Settings::findIndexStrict(name);
+    const auto * ptr = tryGetConstraint(setting_index);
+    if (ptr)
+        return ptr->max_value;
+    else
+        return {};
+}
+
+
+void SettingsConstraints::setReadOnly(const StringRef & name, bool read_only)
 {
    size_t setting_index = Settings::findIndexStrict(name);
    getConstraintRef(setting_index).read_only = read_only;
 }

-void SettingsConstraints::setMinValue(const String & name, const Field & min_value)
+
+bool SettingsConstraints::isReadOnly(const StringRef & name) const
 {
    size_t setting_index = Settings::findIndexStrict(name);
-    getConstraintRef(setting_index).min_value = Settings::castValueWithoutApplying(setting_index, min_value);
+    const auto * ptr = tryGetConstraint(setting_index);
+    if (ptr)
+        return ptr->read_only;
+    else
+        return false;
 }

-void SettingsConstraints::setMaxValue(const String & name, const Field & max_value)
+
+void SettingsConstraints::set(const StringRef & name, const Field & min_value, const Field & max_value, bool read_only)
 {
    size_t setting_index = Settings::findIndexStrict(name);
-    getConstraintRef(setting_index).max_value = Settings::castValueWithoutApplying(setting_index, max_value);
+    auto & ref = getConstraintRef(setting_index);
+    ref.min_value = min_value;
+    ref.max_value = max_value;
+    ref.read_only = read_only;
+}
+
+
+void SettingsConstraints::get(const StringRef & name, Field & min_value, Field & max_value, bool & read_only) const
+{
+    size_t setting_index = Settings::findIndexStrict(name);
+    const auto * ptr = tryGetConstraint(setting_index);
+    if (ptr)
+    {
+        min_value = ptr->min_value;
+        max_value = ptr->max_value;
+        read_only = ptr->read_only;
+    }
+    else
+    {
+        min_value = Field{};
+        max_value = Field{};
+        read_only = false;
+    }
+}
+
+
+void SettingsConstraints::merge(const SettingsConstraints & other)
+{
+    for (const auto & [setting_index, other_constraint] : other.constraints_by_index)
+    {
+        auto & constraint = constraints_by_index[setting_index];
+        if (!other_constraint.min_value.isNull())
+            constraint.min_value = other_constraint.min_value;
+        if (!other_constraint.max_value.isNull())
+            constraint.max_value = other_constraint.max_value;
+        if (other_constraint.read_only)
+            constraint.read_only = true;
+    }
+}
+
+
+SettingsConstraints::Infos SettingsConstraints::getInfo() const
+{
+    Infos result;
+    result.reserve(constraints_by_index.size());
+    for (const auto & [setting_index, constraint] : constraints_by_index)
+    {
+        result.emplace_back();
+        Info & info = result.back();
+        info.name = Settings::getName(setting_index);
+        info.min = constraint.min_value;
+        info.max = constraint.max_value;
+        info.read_only = constraint.read_only;
+    }
+    return result;
 }


@ -55,7 +151,7 @@ void SettingsConstraints::check(const Settings & current_settings, const Setting
    if (setting_index == Settings::npos)
        return;

-    Field new_value = Settings::castValueWithoutApplying(setting_index, change.value);
+    Field new_value = Settings::valueToCorrespondingType(setting_index, change.value);
    Field current_value = current_settings.get(setting_index);

    /// Setting isn't checked if value wasn't changed.
@ -159,4 +255,15 @@ void SettingsConstraints::loadFromConfig(const String & path_to_constraints, con
    }
 }

+
+bool SettingsConstraints::Constraint::operator==(const Constraint & rhs) const
+{
+    return (read_only == rhs.read_only) && (min_value == rhs.min_value) && (max_value == rhs.max_value);
+}
+
+
+bool operator ==(const SettingsConstraints & lhs, const SettingsConstraints & rhs)
+{
+    return lhs.constraints_by_index == rhs.constraints_by_index;
+}
 }
--- a/dbms/src/Interpreters/SettingsConstraints.h
+++ b/dbms/src/Interpreters/SettingsConstraints.h
@ -58,10 +58,32 @@ public:
    ~SettingsConstraints();

    void clear();
+    bool empty() const { return constraints_by_index.empty(); }

-    void setMinValue(const String & name, const Field & min_value);
-    void setMaxValue(const String & name, const Field & max_value);
-    void setReadOnly(const String & name, bool read_only);
+    void setMinValue(const StringRef & name, const Field & min_value);
+    Field getMinValue(const StringRef & name) const;
+
+    void setMaxValue(const StringRef & name, const Field & max_value);
+    Field getMaxValue(const StringRef & name) const;
+
+    void setReadOnly(const StringRef & name, bool read_only);
+    bool isReadOnly(const StringRef & name) const;
+
+    void set(const StringRef & name, const Field & min_value, const Field & max_value, bool read_only);
+    void get(const StringRef & name, Field & min_value, Field & max_value, bool & read_only) const;
+
+    void merge(const SettingsConstraints & other);
+
+    struct Info
+    {
+        StringRef name;
+        Field min;
+        Field max;
+        bool read_only = false;
+    };
+    using Infos = std::vector<Info>;
+
+    Infos getInfo() const;

    void check(const Settings & current_settings, const SettingChange & change) const;
    void check(const Settings & current_settings, const SettingsChanges & changes) const;
@ -74,12 +96,18 @@ public:
    /// Loads the constraints from configuration file, at "path" prefix in configuration.
    void loadFromConfig(const String & path, const Poco::Util::AbstractConfiguration & config);

+    friend bool operator ==(const SettingsConstraints & lhs, const SettingsConstraints & rhs);
+    friend bool operator !=(const SettingsConstraints & lhs, const SettingsConstraints & rhs) { return !(lhs == rhs); }
+
 private:
    struct Constraint
    {
        bool read_only = false;
        Field min_value;
        Field max_value;
+
+        bool operator ==(const Constraint & rhs) const;
+        bool operator !=(const Constraint & rhs) const { return !(*this == rhs); }
    };

    Constraint & getConstraintRef(size_t index);
--- a/dbms/src/AggregateFunctions/AggregateFunctionAvg.h
+++ b/dbms/src/AggregateFunctions/AggregateFunctionAvg.h
@ -31,9 +31,9 @@ struct AggregateFunctionAvgData
            if constexpr (std::numeric_limits<ResultT>::is_iec559)
                return static_cast<ResultT>(sum) / count; /// allow division by zero

-        if (!count)
-            throw Exception("AggregateFunctionAvg with zero values", ErrorCodes::LOGICAL_ERROR);
-        return static_cast<ResultT>(sum) / count;
+        if (count == 0)
+            return static_cast<ResultT>(0);
+        return static_cast<ResultT>(sum / count);
    }
 };

@ -43,10 +43,10 @@ template <typename T, typename Data>
 class AggregateFunctionAvg final : public IAggregateFunctionDataHelper<Data, AggregateFunctionAvg<T, Data>>
 {
 public:
-    using ResultType = std::conditional_t<IsDecimalNumber<T>, Decimal128, Float64>;
-    using ResultDataType = std::conditional_t<IsDecimalNumber<T>, DataTypeDecimal<Decimal128>, DataTypeNumber<Float64>>;
+    using ResultType = std::conditional_t<IsDecimalNumber<T>, T, Float64>;
+    using ResultDataType = std::conditional_t<IsDecimalNumber<T>, DataTypeDecimal<T>, DataTypeNumber<Float64>>;
    using ColVecType = std::conditional_t<IsDecimalNumber<T>, ColumnDecimal<T>, ColumnVector<T>>;
-    using ColVecResult = std::conditional_t<IsDecimalNumber<T>, ColumnDecimal<Decimal128>, ColumnVector<Float64>>;
+    using ColVecResult = std::conditional_t<IsDecimalNumber<T>, ColumnDecimal<T>, ColumnVector<Float64>>;

    /// ctor for native types
    AggregateFunctionAvg(const DataTypes & argument_types_)
--- a/dbms/src/AggregateFunctions/AggregateFunctionCount.h
+++ b/dbms/src/AggregateFunctions/AggregateFunctionCount.h
@ -64,6 +64,12 @@ public:
    }

    const char * getHeaderFilePath() const override { return __FILE__; }
+
+    /// Reset the state to specified value. This function is not the part of common interface.
+    void set(AggregateDataPtr place, UInt64 new_count)
+    {
+        data(place).count = new_count;
+    }
 };


--- a/dbms/src/AggregateFunctions/AggregateFunctionEntropy.h
+++ b/dbms/src/AggregateFunctions/AggregateFunctionEntropy.h
@ -55,7 +55,7 @@ struct EntropyData
    void merge(const EntropyData & rhs)
    {
        for (const auto & pair : rhs.map)
-            map[pair.getFirst()] += pair.getSecond();
+            map[pair.getKey()] += pair.getMapped();
    }

    void serialize(WriteBuffer & buf) const
@ -77,12 +77,12 @@ struct EntropyData
    {
        UInt64 total_value = 0;
        for (const auto & pair : map)
-            total_value += pair.getSecond();
+            total_value += pair.getMapped();

        Float64 shannon_entropy = 0;
        for (const auto & pair : map)
        {
-            Float64 frequency = Float64(pair.getSecond()) / total_value;
+            Float64 frequency = Float64(pair.getMapped()) / total_value;
            shannon_entropy -= frequency * log2(frequency);
        }

--- a/dbms/src/AggregateFunctions/AggregateFunctionGroupBitmap.h
+++ b/dbms/src/AggregateFunctions/AggregateFunctionGroupBitmap.h
@ -90,6 +90,10 @@ public:
    {
        Data & data_lhs = this->data(place);
        const Data & data_rhs = this->data(rhs);
+
+        if (!data_rhs.doneFirst)
+            return;
+
        if (!data_lhs.doneFirst)
        {
            data_lhs.doneFirst = true;
--- a/dbms/src/AggregateFunctions/AggregateFunctionGroupBitmapData.h
+++ b/dbms/src/AggregateFunctions/AggregateFunctionGroupBitmapData.h
@ -581,6 +581,23 @@ public:
        return max_val;
    }

+    /**
+     * Replace value
+     */
+    void rb_replace(const UInt32 * from_vals, const UInt32 * to_vals, size_t num)
+    {
+        if (isSmall())
+            toLarge();
+        for (size_t i = 0; i < num; ++i)
+        {
+            if (from_vals[i] == to_vals[i])
+                continue;
+            bool changed = roaring_bitmap_remove_checked(rb, from_vals[i]);
+            if (changed)
+                roaring_bitmap_add(rb, to_vals[i]);
+        }
+    }
+
 private:
    /// To read and write the DB Buffer directly, migrate code from CRoaring
    void db_roaring_bitmap_add_many(DB::ReadBuffer & dbBuf, roaring_bitmap_t * r, size_t n_args)
--- a/dbms/src/AggregateFunctions/AggregateFunctionMinMaxAny.h
+++ b/dbms/src/AggregateFunctions/AggregateFunctionMinMaxAny.h
@ -673,15 +673,15 @@ struct AggregateFunctionAnyHeavyData : Data
 };


-template <typename Data, bool AllocatesMemoryInArena>
-class AggregateFunctionsSingleValue final : public IAggregateFunctionDataHelper<Data, AggregateFunctionsSingleValue<Data, AllocatesMemoryInArena>>
+template <typename Data, bool use_arena>
+class AggregateFunctionsSingleValue final : public IAggregateFunctionDataHelper<Data, AggregateFunctionsSingleValue<Data, use_arena>>
 {
 private:
    DataTypePtr & type;

 public:
    AggregateFunctionsSingleValue(const DataTypePtr & type_)
-        : IAggregateFunctionDataHelper<Data, AggregateFunctionsSingleValue<Data, AllocatesMemoryInArena>>({type_}, {})
+        : IAggregateFunctionDataHelper<Data, AggregateFunctionsSingleValue<Data, use_arena>>({type_}, {})
        , type(this->argument_types[0])
    {
        if (StringRef(Data::name()) == StringRef("min")
@ -722,7 +722,7 @@ public:

    bool allocatesMemoryInArena() const override
    {
-        return AllocatesMemoryInArena;
+        return use_arena;
    }

    void insertResultInto(ConstAggregateDataPtr place, IColumn & to) const override
--- a/dbms/src/AggregateFunctions/AggregateFunctionQuantile.cpp
+++ b/dbms/src/AggregateFunctions/AggregateFunctionQuantile.cpp
@ -16,11 +16,11 @@ namespace ErrorCodes
 namespace
 {

-template <typename Value, bool FloatReturn> using FuncQuantile = AggregateFunctionQuantile<Value, QuantileReservoirSampler<Value>, NameQuantile, false, std::conditional_t<FloatReturn, Float64, void>, false>;
-template <typename Value, bool FloatReturn> using FuncQuantiles = AggregateFunctionQuantile<Value, QuantileReservoirSampler<Value>, NameQuantiles, false, std::conditional_t<FloatReturn, Float64, void>, true>;
+template <typename Value, bool float_return> using FuncQuantile = AggregateFunctionQuantile<Value, QuantileReservoirSampler<Value>, NameQuantile, false, std::conditional_t<float_return, Float64, void>, false>;
+template <typename Value, bool float_return> using FuncQuantiles = AggregateFunctionQuantile<Value, QuantileReservoirSampler<Value>, NameQuantiles, false, std::conditional_t<float_return, Float64, void>, true>;

-template <typename Value, bool FloatReturn> using FuncQuantileDeterministic = AggregateFunctionQuantile<Value, QuantileReservoirSamplerDeterministic<Value>, NameQuantileDeterministic, true, std::conditional_t<FloatReturn, Float64, void>, false>;
-template <typename Value, bool FloatReturn> using FuncQuantilesDeterministic = AggregateFunctionQuantile<Value, QuantileReservoirSamplerDeterministic<Value>, NameQuantilesDeterministic, true, std::conditional_t<FloatReturn, Float64, void>, true>;
+template <typename Value, bool float_return> using FuncQuantileDeterministic = AggregateFunctionQuantile<Value, QuantileReservoirSamplerDeterministic<Value>, NameQuantileDeterministic, true, std::conditional_t<float_return, Float64, void>, false>;
+template <typename Value, bool float_return> using FuncQuantilesDeterministic = AggregateFunctionQuantile<Value, QuantileReservoirSamplerDeterministic<Value>, NameQuantilesDeterministic, true, std::conditional_t<float_return, Float64, void>, true>;

 template <typename Value, bool _> using FuncQuantileExact = AggregateFunctionQuantile<Value, QuantileExact<Value>, NameQuantileExact, false, void, false>;
 template <typename Value, bool _> using FuncQuantilesExact = AggregateFunctionQuantile<Value, QuantileExact<Value>, NameQuantilesExact, false, void, true>;
@ -40,11 +40,11 @@ template <typename Value, bool _> using FuncQuantilesTiming = AggregateFunctionQ
 template <typename Value, bool _> using FuncQuantileTimingWeighted = AggregateFunctionQuantile<Value, QuantileTiming<Value>, NameQuantileTimingWeighted, true, Float32, false>;
 template <typename Value, bool _> using FuncQuantilesTimingWeighted = AggregateFunctionQuantile<Value, QuantileTiming<Value>, NameQuantilesTimingWeighted, true, Float32, true>;

-template <typename Value, bool FloatReturn> using FuncQuantileTDigest = AggregateFunctionQuantile<Value, QuantileTDigest<Value>, NameQuantileTDigest, false, std::conditional_t<FloatReturn, Float32, void>, false>;
-template <typename Value, bool FloatReturn> using FuncQuantilesTDigest = AggregateFunctionQuantile<Value, QuantileTDigest<Value>, NameQuantilesTDigest, false, std::conditional_t<FloatReturn, Float32, void>, true>;
+template <typename Value, bool float_return> using FuncQuantileTDigest = AggregateFunctionQuantile<Value, QuantileTDigest<Value>, NameQuantileTDigest, false, std::conditional_t<float_return, Float32, void>, false>;
+template <typename Value, bool float_return> using FuncQuantilesTDigest = AggregateFunctionQuantile<Value, QuantileTDigest<Value>, NameQuantilesTDigest, false, std::conditional_t<float_return, Float32, void>, true>;

-template <typename Value, bool FloatReturn> using FuncQuantileTDigestWeighted = AggregateFunctionQuantile<Value, QuantileTDigest<Value>, NameQuantileTDigestWeighted, true, std::conditional_t<FloatReturn, Float32, void>, false>;
-template <typename Value, bool FloatReturn> using FuncQuantilesTDigestWeighted = AggregateFunctionQuantile<Value, QuantileTDigest<Value>, NameQuantilesTDigestWeighted, true, std::conditional_t<FloatReturn, Float32, void>, true>;
+template <typename Value, bool float_return> using FuncQuantileTDigestWeighted = AggregateFunctionQuantile<Value, QuantileTDigest<Value>, NameQuantileTDigestWeighted, true, std::conditional_t<float_return, Float32, void>, false>;
+template <typename Value, bool float_return> using FuncQuantilesTDigestWeighted = AggregateFunctionQuantile<Value, QuantileTDigest<Value>, NameQuantilesTDigestWeighted, true, std::conditional_t<float_return, Float32, void>, true>;


 template <template <typename, bool> class Function>
--- a/dbms/src/AggregateFunctions/QuantileExactWeighted.h
+++ b/dbms/src/AggregateFunctions/QuantileExactWeighted.h
@ -58,7 +58,7 @@ struct QuantileExactWeighted
    void merge(const QuantileExactWeighted & rhs)
    {
        for (const auto & pair : rhs.map)
-            map[pair.getFirst()] += pair.getSecond();
+            map[pair.getKey()] += pair.getMapped();
    }

    void serialize(WriteBuffer & buf) const
@ -93,7 +93,7 @@ struct QuantileExactWeighted
        UInt64 sum_weight = 0;
        for (const auto & pair : map)
        {
-            sum_weight += pair.getSecond();
+            sum_weight += pair.getMapped();
            array[i] = pair.getValue();
            ++i;
        }
@ -143,7 +143,7 @@ struct QuantileExactWeighted
        UInt64 sum_weight = 0;
        for (const auto & pair : map)
        {
-            sum_weight += pair.getSecond();
+            sum_weight += pair.getMapped();
            array[i] = pair.getValue();
            ++i;
        }
--- a/dbms/src/AggregateFunctions/ReservoirSampler.h
+++ b/dbms/src/AggregateFunctions/ReservoirSampler.h
@ -31,7 +31,7 @@ namespace ReservoirSamplerOnEmpty
    };
 }

-template <typename ResultType, bool IsFloatingPoint>
+template <typename ResultType, bool is_float>
 struct NanLikeValueConstructor
 {
    static ResultType getValue()
@ -109,8 +109,11 @@ public:
    double quantileInterpolated(double level)
    {
        if (samples.empty())
+        {
+            if (DB::IsDecimalNumber<T>)
+                return 0;
            return onEmpty<double>();
-
+        }
        sortIfNeeded();

        double index = std::max(0., std::min(samples.size() - 1., level * (samples.size() - 1)));
--- a/dbms/src/Client/Connection.cpp
+++ b/dbms/src/Client/Connection.cpp
@ -30,6 +30,7 @@

 namespace CurrentMetrics
 {
+    extern const Metric SendScalars;
    extern const Metric SendExternalTables;
 }

@ -441,7 +442,7 @@ void Connection::sendCancel()
 }


-void Connection::sendData(const Block & block, const String & name)
+void Connection::sendData(const Block & block, const String & name, bool scalar)
 {
    //LOG_TRACE(log_wrapper.get(), "Sending data");

@ -455,7 +456,10 @@ void Connection::sendData(const Block & block, const String & name)
        block_out = std::make_shared<NativeBlockOutputStream>(*maybe_compressed_out, server_revision, block.cloneEmpty());
    }

-    writeVarUInt(Protocol::Client::Data, *out);
+    if (scalar)
+        writeVarUInt(Protocol::Client::Scalar, *out);
+    else
+        writeVarUInt(Protocol::Client::Data, *out);
    writeStringBinary(name, *out);

    size_t prev_bytes = out->count();
@ -484,6 +488,44 @@ void Connection::sendPreparedData(ReadBuffer & input, size_t size, const String
 }


+void Connection::sendScalarsData(Scalars & data)
+{
+    if (data.empty())
+        return;
+
+    Stopwatch watch;
+    size_t out_bytes = out ? out->count() : 0;
+    size_t maybe_compressed_out_bytes = maybe_compressed_out ? maybe_compressed_out->count() : 0;
+    size_t rows = 0;
+
+    CurrentMetrics::Increment metric_increment{CurrentMetrics::SendScalars};
+
+    for (auto & elem : data)
+    {
+        rows += elem.second.rows();
+        sendData(elem.second, elem.first, true /* scalar */);
+    }
+
+    out_bytes = out->count() - out_bytes;
+    maybe_compressed_out_bytes = maybe_compressed_out->count() - maybe_compressed_out_bytes;
+    double elapsed = watch.elapsedSeconds();
+
+    std::stringstream msg;
+    msg << std::fixed << std::setprecision(3);
+    msg << "Sent data for " << data.size() << " scalars, total " << rows << " rows in " << elapsed << " sec., "
+        << static_cast<size_t>(rows / watch.elapsedSeconds()) << " rows/sec., "
+        << maybe_compressed_out_bytes / 1048576.0 << " MiB (" << maybe_compressed_out_bytes / 1048576.0 / watch.elapsedSeconds() << " MiB/sec.)";
+
+    if (compression == Protocol::Compression::Enable)
+        msg << ", compressed " << static_cast<double>(maybe_compressed_out_bytes) / out_bytes << " times to "
+            << out_bytes / 1048576.0 << " MiB (" << out_bytes / 1048576.0 / watch.elapsedSeconds() << " MiB/sec.)";
+    else
+        msg << ", no compression.";
+
+    LOG_DEBUG(log_wrapper.get(), msg.rdbuf());
+}
+
+
 void Connection::sendExternalTablesData(ExternalTablesData & data)
 {
    if (data.empty())
--- a/dbms/src/Client/Connection.h
+++ b/dbms/src/Client/Connection.h
@ -133,7 +133,9 @@ public:

    void sendCancel();
    /// Send block of data; if name is specified, server will write it to external (temporary) table of that name.
-    void sendData(const Block & block, const String & name = "");
+    void sendData(const Block & block, const String & name = "", bool scalar = false);
+    /// Send all scalars.
+    void sendScalarsData(Scalars & data);
    /// Send all contents of external (temporary) tables.
    void sendExternalTablesData(ExternalTablesData & data);

--- a/dbms/src/Client/MultiplexedConnections.cpp
+++ b/dbms/src/Client/MultiplexedConnections.cpp
@ -51,6 +51,21 @@ MultiplexedConnections::MultiplexedConnections(
    active_connection_count = connections.size();
 }

+void MultiplexedConnections::sendScalarsData(Scalars & data)
+{
+    std::lock_guard lock(cancel_mutex);
+
+    if (!sent_query)
+        throw Exception("Cannot send scalars data: query not yet sent.", ErrorCodes::LOGICAL_ERROR);
+
+    for (ReplicaState & state : replica_states)
+    {
+        Connection * connection = state.connection;
+        if (connection != nullptr)
+            connection->sendScalarsData(data);
+    }
+}
+
 void MultiplexedConnections::sendExternalTablesData(std::vector<ExternalTablesData> & data)
 {
    std::lock_guard lock(cancel_mutex);
--- a/dbms/src/Client/MultiplexedConnections.h
+++ b/dbms/src/Client/MultiplexedConnections.h
@ -27,6 +27,8 @@ public:
        std::vector<IConnectionPool::Entry> && connections,
        const Settings & settings_, const ThrottlerPtr & throttler_);

+    /// Send all scalars to replicas.
+    void sendScalarsData(Scalars & data);
    /// Send all content of external tables to replicas.
    void sendExternalTablesData(std::vector<ExternalTablesData> & data);

--- a/dbms/src/Columns/ColumnLowCardinality.cpp
+++ b/dbms/src/Columns/ColumnLowCardinality.cpp
@ -35,7 +35,7 @@ namespace

        data.resize(hash_map.size());
        for (const auto & val : hash_map)
-            data[val.getSecond()] = val.getFirst();
+            data[val.getMapped()] = val.getKey();

        for (auto & ind : index)
            ind = hash_map[ind];
--- a/dbms/src/Columns/ColumnSet.h
+++ b/dbms/src/Columns/ColumnSet.h
@ -1,6 +1,7 @@
 #pragma once

 #include <Columns/IColumnDummy.h>
+#include <Core/Field.h>


 namespace DB
@ -28,6 +29,9 @@ public:

    ConstSetPtr getData() const { return data; }

+    // Used only for debugging, making it DUMPABLE
+    Field operator[](size_t) const override { return {}; }
+
 private:
    ConstSetPtr data;
 };
--- a/dbms/src/Columns/ColumnVector.cpp
+++ b/dbms/src/Columns/ColumnVector.cpp
@ -112,7 +112,7 @@ void ColumnVector<T>::getPermutation(bool reverse, size_t limit, int nan_directi
    else
    {
        /// A case for radix sort
-        if constexpr (std::is_arithmetic_v<T> && !std::is_same_v<T, UInt128>)
+        if constexpr (is_arithmetic_v<T> && !std::is_same_v<T, UInt128>)
        {
            /// Thresholds on size. Lower threshold is arbitrary. Upper threshold is chosen by the type for histogram counters.
            if (s >= 256 && s <= std::numeric_limits<UInt32>::max())
--- a/dbms/src/Common/ColumnsHashing.h
+++ b/dbms/src/Common/ColumnsHashing.h
@ -359,7 +359,7 @@ struct HashMethodSingleLowCardinalityColumn : public SingleColumnMethod

        if constexpr (has_mapped)
        {
-            auto & mapped = *lookupResultGetMapped(it);
+            auto & mapped = it->getMapped();
            if (inserted)
            {
                new (&mapped) Mapped();
--- a/dbms/src/Common/ColumnsHashingImpl.h
+++ b/dbms/src/Common/ColumnsHashingImpl.h
@ -174,13 +174,13 @@ protected:

        [[maybe_unused]] Mapped * cached = nullptr;
        if constexpr (has_mapped)
-            cached = lookupResultGetMapped(it);
+            cached = &it->getMapped();

        if (inserted)
        {
            if constexpr (has_mapped)
            {
-                new(lookupResultGetMapped(it)) Mapped();
+                new (&it->getMapped()) Mapped();
            }
        }

@ -191,18 +191,18 @@ protected:

            if constexpr (has_mapped)
            {
-                cache.value.first = *lookupResultGetKey(it);
-                cache.value.second = *lookupResultGetMapped(it);
+                cache.value.first = it->getKey();
+                cache.value.second = it->getMapped();
                cached = &cache.value.second;
            }
            else
            {
-                cache.value = *lookupResultGetKey(it);
+                cache.value = it->getKey();
            }
        }

        if constexpr (has_mapped)
-            return EmplaceResult(*lookupResultGetMapped(it), *cached, inserted);
+            return EmplaceResult(it->getMapped(), *cached, inserted);
        else
            return EmplaceResult(inserted);
    }
@ -233,7 +233,7 @@ protected:
                cache.value.first = key;
                if (it)
                {
-                    cache.value.second = *lookupResultGetMapped(it);
+                    cache.value.second = it->getMapped();
                }
            }
            else
@ -243,7 +243,7 @@ protected:
        }

        if constexpr (has_mapped)
-            return FindResult(it ? lookupResultGetMapped(it) : nullptr, it != nullptr);
+            return FindResult(it ? &it->getMapped() : nullptr, it != nullptr);
        else
            return FindResult(it != nullptr);
    }
--- a/dbms/src/Common/CurrentMetrics.cpp
+++ b/dbms/src/Common/CurrentMetrics.cpp
@ -21,6 +21,7 @@
    M(OpenFileForWrite, "Number of files open for writing") \
    M(Read, "Number of read (read, pread, io_getevents, etc.) syscalls in fly") \
    M(Write, "Number of write (write, pwrite, io_getevents, etc.) syscalls in fly") \
+    M(SendScalars, "Number of connections that are sending data for scalars to remote servers.") \
    M(SendExternalTables, "Number of connections that are sending data for external tables to remote servers. External tables are used to implement GLOBAL IN and GLOBAL JOIN operators with distributed subqueries.") \
    M(QueryThread, "Number of query processing threads") \
    M(ReadonlyReplica, "Number of Replicated tables that are currently in readonly state due to re-initialization after ZooKeeper session loss or due to startup without ZooKeeper configured.") \
--- a/dbms/src/Common/DiskSpaceMonitor.cpp
+++ b/dbms/src/Common/DiskSpaceMonitor.cpp
@ -193,7 +193,7 @@ DiskSelector::DiskSelector(const Poco::Util::AbstractConfiguration & config, con

        if (has_space_ratio)
        {
-            auto ratio = config.getDouble(config_prefix + ".keep_free_space_ratio");
+            auto ratio = config.getDouble(disk_config_prefix + ".keep_free_space_ratio");
            if (ratio < 0 || ratio > 1)
                throw Exception("'keep_free_space_ratio' have to be between 0 and 1",
                                ErrorCodes::EXCESSIVE_ELEMENT_IN_CONFIG);
@ -292,7 +292,7 @@ Volume::Volume(
                                    formatReadableSizeWithBinarySuffix(max_data_part_size) << ")");
    }
    constexpr UInt64 MIN_PART_SIZE = 8u * 1024u * 1024u;
-    if (max_data_part_size < MIN_PART_SIZE)
+    if (max_data_part_size != 0 && max_data_part_size < MIN_PART_SIZE)
        LOG_WARNING(logger, "Volume " << backQuote(name) << " max_data_part_size is too low ("
            << formatReadableSizeWithBinarySuffix(max_data_part_size) << " < "
            << formatReadableSizeWithBinarySuffix(MIN_PART_SIZE) << ")");
--- a/dbms/src/Common/ErrorCodes.cpp
+++ b/dbms/src/Common/ErrorCodes.cpp
@ -155,7 +155,7 @@ namespace ErrorCodes
    extern const int NOT_FOUND_FUNCTION_ELEMENT_FOR_AGGREGATE = 147;
    extern const int NOT_FOUND_RELATION_ELEMENT_FOR_CONDITION = 148;
    extern const int NOT_FOUND_RHS_ELEMENT_FOR_CONDITION = 149;
-    extern const int NO_ATTRIBUTES_LISTED = 150;
+    extern const int EMPTY_LIST_OF_ATTRIBUTES_PASSED = 150;
    extern const int INDEX_OF_COLUMN_IN_SORT_CLAUSE_IS_OUT_OF_RANGE = 151;
    extern const int UNKNOWN_DIRECTION_OF_SORTING = 152;
    extern const int ILLEGAL_DIVISION = 153;
@ -361,7 +361,7 @@ namespace ErrorCodes
    extern const int PART_IS_TEMPORARILY_LOCKED = 384;
    extern const int MULTIPLE_STREAMS_REQUIRED = 385;
    extern const int NO_COMMON_TYPE = 386;
-    extern const int EXTERNAL_LOADABLE_ALREADY_EXISTS = 387;
+    extern const int DICTIONARY_ALREADY_EXISTS = 387;
    extern const int CANNOT_ASSIGN_OPTIMIZE = 388;
    extern const int INSERT_WAS_DEDUPLICATED = 389;
    extern const int CANNOT_GET_CREATE_TABLE_QUERY = 390;
@ -459,6 +459,11 @@ namespace ErrorCodes
    extern const int DICTIONARY_ACCESS_DENIED = 482;
    extern const int TOO_MANY_REDIRECTS = 483;
    extern const int INTERNAL_REDIS_ERROR = 484;
+    extern const int SCALAR_ALREADY_EXISTS = 485;
+    extern const int UNKNOWN_SCALAR = 486;
+    extern const int CANNOT_GET_CREATE_DICTIONARY_QUERY = 487;
+    extern const int UNKNOWN_DICTIONARY = 488;
+    extern const int INCORRECT_DICTIONARY_DEFINITION = 489;

    extern const int KEEPER_EXCEPTION = 999;
    extern const int POCO_EXCEPTION = 1000;
--- a/dbms/src/Common/HashTable/ClearableHashMap.h
+++ b/dbms/src/Common/HashTable/ClearableHashMap.h
@ -14,12 +14,6 @@ struct ClearableHashMapCell : public ClearableHashTableCell<Key, HashMapCell<Key
        : Base::BaseCell(value_, state), Base::version(state.version) {}
 };

-template<typename Key, typename Mapped, typename Hash>
-ALWAYS_INLINE inline auto lookupResultGetKey(ClearableHashMapCell<Key, Mapped, Hash> * cell) { return &cell->getFirst(); }
-
-template<typename Key, typename Mapped, typename Hash>
-ALWAYS_INLINE inline auto lookupResultGetMapped(ClearableHashMapCell<Key, Mapped, Hash> * cell) { return &cell->getSecond(); }
-
 template
 <
    typename Key,
@ -31,20 +25,16 @@ template
 class ClearableHashMap : public HashTable<Key, ClearableHashMapCell<Key, Mapped, Hash>, Hash, Grower, Allocator>
 {
 public:
-    using key_type = Key;
-    using mapped_type = Mapped;
-    using value_type = typename ClearableHashMap::cell_type::value_type;
-
-    mapped_type & operator[](Key x)
+    Mapped & operator[](const Key & x)
    {
        typename ClearableHashMap::LookupResult it;
        bool inserted;
        this->emplace(x, it, inserted);

        if (inserted)
-            new(lookupResultGetMapped(it)) mapped_type();
+            new (&it->getMapped()) Mapped();

-        return *lookupResultGetMapped(it);
+        return it->getMapped();
    }

    void clear()
--- a/dbms/src/Common/HashTable/ClearableHashSet.h
+++ b/dbms/src/Common/HashTable/ClearableHashSet.h
@ -48,12 +48,6 @@ struct ClearableHashTableCell : public BaseCell
    ClearableHashTableCell(const Key & key_, const State & state) : BaseCell(key_, state), version(state.version) {}
 };

-template<typename Key, typename BaseCell>
-ALWAYS_INLINE inline auto lookupResultGetKey(ClearableHashTableCell<Key, BaseCell> * cell) { return &cell->key; }
-
-template<typename Key, typename BaseCell>
-ALWAYS_INLINE inline void * lookupResultGetMapped(ClearableHashTableCell<Key, BaseCell> *) { return nullptr; }
-
 template
 <
    typename Key,
@ -64,9 +58,6 @@ template
 class ClearableHashSet : public HashTable<Key, ClearableHashTableCell<Key, HashTableCell<Key, Hash, ClearableHashSetState>>, Hash, Grower, Allocator>
 {
 public:
-    using key_type = Key;
-    using value_type = typename ClearableHashSet::cell_type::value_type;
-
    using Base = HashTable<Key, ClearableHashTableCell<Key, HashTableCell<Key, Hash, ClearableHashSetState>>, Hash, Grower, Allocator>;
    using typename Base::LookupResult;

@ -87,9 +78,6 @@ template
 class ClearableHashSetWithSavedHash: public HashTable<Key, ClearableHashTableCell<Key, HashSetCellWithSavedHash<Key, Hash, ClearableHashSetState>>, Hash, Grower, Allocator>
 {
 public:
-    using key_type = Key;
-    using value_type = typename ClearableHashSetWithSavedHash::cell_type::value_type;
-
    void clear()
    {
        ++this->version;
--- a/dbms/src/Common/HashTable/FixedClearableHashMap.h
+++ b/dbms/src/Common/HashTable/FixedClearableHashMap.h
@ -11,6 +11,8 @@ struct FixedClearableHashMapCell
    using State = ClearableHashSetState;

    using value_type = PairNoInit<Key, Mapped>;
+    using mapped_type = Mapped;
+
    UInt32 version;
    Mapped mapped;

@ -18,11 +20,12 @@ struct FixedClearableHashMapCell
    FixedClearableHashMapCell(const Key &, const State & state) : version(state.version) {}
    FixedClearableHashMapCell(const value_type & value_, const State & state) : version(state.version), mapped(value_.second) {}

-    Mapped & getSecond() { return mapped; }
-    const Mapped & getSecond() const { return mapped; }
+    const VoidKey getKey() const { return {}; }
+    Mapped & getMapped() { return mapped; }
+    const Mapped & getMapped() const { return mapped; }
+
    bool isZero(const State & state) const { return version != state.version; }
    void setZero() { version = 0; }
-    static constexpr bool need_zero_value_storage = false;

    struct CellExt
    {
@ -35,32 +38,33 @@ struct FixedClearableHashMapCell
        }
        Key key;
        FixedClearableHashMapCell * ptr;
-        const Key & getFirst() const { return key; }
-        Mapped & getSecond() { return ptr->mapped; }
-        const Mapped & getSecond() const { return *ptr->mapped; }
+        const Key & getKey() const { return key; }
+        Mapped & getMapped() { return ptr->mapped; }
+        const Mapped & getMapped() const { return *ptr->mapped; }
        const value_type getValue() const { return {key, *ptr->mapped}; }
    };
 };


 template <typename Key, typename Mapped, typename Allocator = HashTableAllocator>
-class FixedClearableHashMap : public FixedHashMap<Key, FixedClearableHashMapCell<Key, Mapped>, Allocator>
+class FixedClearableHashMap : public FixedHashMap<Key, Mapped, FixedClearableHashMapCell<Key, Mapped>, Allocator>
 {
 public:
-    using key_type = Key;
-    using mapped_type = Mapped;
-    using value_type = typename FixedClearableHashMap::cell_type::value_type;
+    using Base = FixedHashMap<Key, Mapped, FixedClearableHashMapCell<Key, Mapped>, Allocator>;
+    using Self = FixedClearableHashMap;
+    using LookupResult = typename Base::LookupResult;

-    mapped_type & operator[](Key x)
+    using Base::Base;
+
+    Mapped & operator[](const Key & x)
    {
-        typename FixedClearableHashMap::iterator it;
+        LookupResult it;
        bool inserted;
        this->emplace(x, it, inserted);
-
        if (inserted)
-            new (&it->second) mapped_type();
+            new (&it->getMapped()) Mapped();

-        return it->second;
+        return it->getMapped();
    }

    void clear()
--- a/dbms/src/Common/HashTable/FixedClearableHashSet.h
+++ b/dbms/src/Common/HashTable/FixedClearableHashSet.h
@ -10,19 +10,23 @@ struct FixedClearableHashTableCell
    using State = ClearableHashSetState;

    using value_type = Key;
-    using mapped_type = void;
+    using mapped_type = VoidMapped;
    UInt32 version;

    FixedClearableHashTableCell() {}
    FixedClearableHashTableCell(const Key &, const State & state) : version(state.version) {}

+    const VoidKey getKey() const { return {}; }
+    VoidMapped getMapped() const { return {}; }
+
    bool isZero(const State & state) const { return version != state.version; }
    void setZero() { version = 0; }
-    static constexpr bool need_zero_value_storage = false;

    struct CellExt
    {
        Key key;
+        const VoidKey getKey() const { return {}; }
+        VoidMapped getMapped() const { return {}; }
        const value_type & getValue() const { return key; }
        void update(Key && key_, FixedClearableHashTableCell *) { key = key_; }
    };
@ -34,8 +38,6 @@ class FixedClearableHashSet : public FixedHashTable<Key, FixedClearableHashTable
 {
 public:
    using Base = FixedHashTable<Key, FixedClearableHashTableCell<Key>, Allocator>;
-    using key_type = Key;
-    using value_type = typename FixedClearableHashSet::cell_type::value_type;
    using LookupResult = typename Base::LookupResult;

    void clear()
--- a/dbms/src/Common/HashTable/FixedHashMap.h
+++ b/dbms/src/Common/HashTable/FixedHashMap.h
@ -13,18 +13,19 @@ struct FixedHashMapCell
    using value_type = PairNoInit<Key, Mapped>;
    using mapped_type = TMapped;

-    Mapped mapped;
    bool full;
+    Mapped mapped;

    FixedHashMapCell() {}
    FixedHashMapCell(const Key &, const State &) : full(true) {}
    FixedHashMapCell(const value_type & value_, const State &) : full(true), mapped(value_.second) {}

-    Mapped & getSecond() { return mapped; }
-    const Mapped & getSecond() const { return mapped; }
+    const VoidKey getKey() const { return {}; }
+    Mapped & getMapped() { return mapped; }
+    const Mapped & getMapped() const { return mapped; }
+
    bool isZero(const State &) const { return !full; }
    void setZero() { full = false; }
-    static constexpr bool need_zero_value_storage = false;

    /// Similar to FixedHashSetCell except that we need to contain a pointer to the Mapped field.
    ///  Note that we have to assemble a continuous layout for the value_type on each call of getValue().
@ -40,36 +41,23 @@ struct FixedHashMapCell
        Key key;
        FixedHashMapCell * ptr;

-        const Key & getFirst() const { return key; }
-        Mapped & getSecond() { return ptr->mapped; }
-        const Mapped & getSecond() const { return ptr->mapped; }
+        const Key & getKey() const { return key; }
+        Mapped & getMapped() { return ptr->mapped; }
+        const Mapped & getMapped() const { return ptr->mapped; }
        const value_type getValue() const { return {key, ptr->mapped}; }
    };
 };

-template<typename Key, typename Mapped, typename State>
-ALWAYS_INLINE inline void * lookupResultGetKey(FixedHashMapCell<Key, Mapped, State> *)
-{ return nullptr; }
-
-template<typename Key, typename Mapped, typename State>
-ALWAYS_INLINE inline auto lookupResultGetMapped(FixedHashMapCell<Key, Mapped, State> * cell)
-{ return &cell->getSecond(); }
-
-template <typename Key, typename Mapped, typename Allocator = HashTableAllocator>
-class FixedHashMap : public FixedHashTable<Key, FixedHashMapCell<Key, Mapped>, Allocator>
+template <typename Key, typename Mapped, typename Cell = FixedHashMapCell<Key, Mapped>, typename Allocator = HashTableAllocator>
+class FixedHashMap : public FixedHashTable<Key, Cell, Allocator>
 {
 public:
-    using Base = FixedHashTable<Key, FixedHashMapCell<Key, Mapped>, Allocator>;
+    using Base = FixedHashTable<Key, Cell, Allocator>;
    using Self = FixedHashMap;
-    using key_type = Key;
-    using Cell = typename Base::cell_type;
-    using value_type = typename Cell::value_type;
-    using mapped_type = typename Cell::Mapped;
+    using LookupResult = typename Base::LookupResult;

    using Base::Base;

-    using LookupResult = typename Base::LookupResult;
-
    template <typename Func>
    void ALWAYS_INLINE mergeToViaEmplace(Self & that, Func && func)
    {
@ -77,8 +65,8 @@ public:
        {
            typename Self::LookupResult res_it;
            bool inserted;
-            that.emplace(it->getFirst(), res_it, inserted, it.getHash());
-            func(*lookupResultGetMapped(res_it), it->getSecond(), inserted);
+            that.emplace(it->getKey(), res_it, inserted, it.getHash());
+            func(res_it->getMapped(), it->getMapped(), inserted);
        }
    }

@ -87,11 +75,11 @@ public:
    {
        for (auto it = this->begin(), end = this->end(); it != end; ++it)
        {
-            auto res_it = that.find(it->getFirst(), it.getHash());
+            auto res_it = that.find(it->getKey(), it.getHash());
            if (!res_it)
-                func(it->getSecond(), it->getSecond(), false);
+                func(it->getMapped(), it->getMapped(), false);
            else
-                func(*lookupResultGetMapped(res_it), it->getSecond(), true);
+                func(res_it->getMapped(), it->getMapped(), true);
        }
    }

@ -99,24 +87,24 @@ public:
    void forEachValue(Func && func)
    {
        for (auto & v : *this)
-            func(v.getFirst(), v.getSecond());
+            func(v.getKey(), v.getMapped());
    }

    template <typename Func>
    void forEachMapped(Func && func)
    {
        for (auto & v : *this)
-            func(v.getSecond());
+            func(v.getMapped());
    }

-    mapped_type & ALWAYS_INLINE operator[](Key x)
+    Mapped & ALWAYS_INLINE operator[](const Key & x)
    {
-        typename Base::LookupResult it;
+        LookupResult it;
        bool inserted;
        this->emplace(x, it, inserted);
        if (inserted)
-            new (it) mapped_type();
+            new (&it->getMapped()) Mapped();

-        return it;
+        return it->getMapped();
    }
 };
--- a/dbms/src/Common/HashTable/FixedHashSet.h
+++ b/dbms/src/Common/HashTable/FixedHashSet.h
@ -6,14 +6,15 @@ template <typename Key, typename Allocator = HashTableAllocator>
 class FixedHashSet : public FixedHashTable<Key, FixedHashTableCell<Key>, Allocator>
 {
 public:
-    using Base = FixedHashTable<Key, FixedHashTableCell<Key>, Allocator>;
+    using Cell = FixedHashTableCell<Key>;
+    using Base = FixedHashTable<Key, Cell, Allocator>;
    using Self = FixedHashSet;

    void merge(const Self & rhs)
    {
        for (size_t i = 0; i < Base::BUFFER_SIZE; ++i)
            if (Base::buf[i].isZero(*this) && !rhs.buf[i].isZero(*this))
-                Base::buf[i] = rhs.buf[i];
+                new (&Base::buf[i]) Cell(rhs.buf[i]);
    }

    /// NOTE: Currently this method isn't used. When it does, the ReadBuffer should
--- a/dbms/src/Common/HashTable/FixedHashTable.h
+++ b/dbms/src/Common/HashTable/FixedHashTable.h
@ -8,12 +8,15 @@ struct FixedHashTableCell
    using State = TState;

    using value_type = Key;
-    using mapped_type = void;
+    using mapped_type = VoidMapped;
    bool full;

    FixedHashTableCell() {}
    FixedHashTableCell(const Key &, const State &) : full(true) {}

+    const VoidKey getKey() const { return {}; }
+    VoidMapped getMapped() const { return {}; }
+
    bool isZero(const State &) const { return !full; }
    void setZero() { full = false; }
    static constexpr bool need_zero_value_storage = false;
@ -28,6 +31,8 @@ struct FixedHashTableCell
    {
        Key key;

+        const VoidKey getKey() const { return {}; }
+        VoidMapped getMapped() const { return {}; }
        const value_type & getValue() const { return key; }
        void update(Key && key_, FixedHashTableCell *) { key = key_; }
    };
@ -53,7 +58,7 @@ struct FixedHashTableCell
 template <typename Key, typename Cell, typename Allocator>
 class FixedHashTable : private boost::noncopyable, protected Allocator, protected Cell::State
 {
-    static constexpr size_t BUFFER_SIZE = 1ULL << (sizeof(Key) * 8);
+    static constexpr size_t NUM_CELLS = 1ULL << (sizeof(Key) * 8);

 protected:
    friend class const_iterator;
@ -61,12 +66,11 @@ protected:
    friend class Reader;

    using Self = FixedHashTable;
-    using cell_type = Cell;

    size_t m_size = 0; /// Amount of elements
-    Cell * buf; /// A piece of memory for all elements except the element with zero key.
+    Cell * buf; /// A piece of memory for all elements.

-    void alloc() { buf = reinterpret_cast<Cell *>(Allocator::alloc(BUFFER_SIZE * sizeof(Cell))); }
+    void alloc() { buf = reinterpret_cast<Cell *>(Allocator::alloc(NUM_CELLS * sizeof(Cell))); }

    void free()
    {
@ -111,7 +115,7 @@ protected:
            ++ptr;

            /// Skip empty cells in the main buffer.
-            auto buf_end = container->buf + container->BUFFER_SIZE;
+            auto buf_end = container->buf + container->NUM_CELLS;
            while (ptr < buf_end && ptr->isZero(*container))
                ++ptr;

@ -140,8 +144,9 @@ protected:

 public:
    using key_type = Key;
-    using value_type = typename Cell::value_type;
    using mapped_type = typename Cell::mapped_type;
+    using value_type = typename Cell::value_type;
+    using cell_type = Cell;

    using LookupResult = Cell *;
    using ConstLookupResult = const Cell *;
@ -239,7 +244,7 @@ public:
            return end();

        const Cell * ptr = buf;
-        auto buf_end = buf + BUFFER_SIZE;
+        auto buf_end = buf + NUM_CELLS;
        while (ptr < buf_end && ptr->isZero(*this))
            ++ptr;

@ -254,21 +259,21 @@ public:
            return end();

        Cell * ptr = buf;
-        auto buf_end = buf + BUFFER_SIZE;
+        auto buf_end = buf + NUM_CELLS;
        while (ptr < buf_end && ptr->isZero(*this))
            ++ptr;

        return iterator(this, ptr);
    }

-    const_iterator end() const { return const_iterator(this, buf + BUFFER_SIZE); }
+    const_iterator end() const { return const_iterator(this, buf + NUM_CELLS); }
    const_iterator cend() const { return end(); }
-    iterator end() { return iterator(this, buf + BUFFER_SIZE); }
+    iterator end() { return iterator(this, buf + NUM_CELLS); }


 public:
    /// The last parameter is unused but exists for compatibility with HashTable interface.
-    void ALWAYS_INLINE emplace(Key x, LookupResult & it, bool & inserted, size_t /* hash */ = 0)
+    void ALWAYS_INLINE emplace(const Key & x, LookupResult & it, bool & inserted, size_t /* hash */ = 0)
    {
        it = &buf[x];

@ -288,40 +293,31 @@ public:
        std::pair<LookupResult, bool> res;
        emplace(Cell::getKey(x), res.first, res.second);
        if (res.second)
-            insertSetMapped(lookupResultGetMapped(res.first), x);
+            insertSetMapped(res.first->getMapped(), x);

        return res;
    }

-    LookupResult ALWAYS_INLINE find(Key x)
-    {
-        return !buf[x].isZero(*this) ? &buf[x] : nullptr;
-    }
+    LookupResult ALWAYS_INLINE find(const Key & x) { return !buf[x].isZero(*this) ? &buf[x] : nullptr; }

-    ConstLookupResult ALWAYS_INLINE find(Key x) const
-    {
-        return const_cast<std::decay_t<decltype(*this)> *>(this)->find(x);
-    }
+    ConstLookupResult ALWAYS_INLINE find(const Key & x) const { return const_cast<std::decay_t<decltype(*this)> *>(this)->find(x); }

-    LookupResult ALWAYS_INLINE find(Key, size_t hash_value)
-    {
-        return !buf[hash_value].isZero(*this) ? &buf[hash_value] : nullptr;
-    }
+    LookupResult ALWAYS_INLINE find(const Key &, size_t hash_value) { return !buf[hash_value].isZero(*this) ? &buf[hash_value] : nullptr; }

-    ConstLookupResult ALWAYS_INLINE find(Key key, size_t hash_value) const
+    ConstLookupResult ALWAYS_INLINE find(const Key & key, size_t hash_value) const
    {
        return const_cast<std::decay_t<decltype(*this)> *>(this)->find(key, hash_value);
    }

-    bool ALWAYS_INLINE has(Key x) const { return !buf[x].isZero(*this); }
-    bool ALWAYS_INLINE has(Key, size_t hash_value) const { return !buf[hash_value].isZero(*this); }
+    bool ALWAYS_INLINE has(const Key & x) const { return !buf[x].isZero(*this); }
+    bool ALWAYS_INLINE has(const Key &, size_t hash_value) const { return !buf[hash_value].isZero(*this); }

    void write(DB::WriteBuffer & wb) const
    {
        Cell::State::write(wb);
        DB::writeVarUInt(m_size, wb);

-        for (auto ptr = buf, buf_end = buf + BUFFER_SIZE; ptr < buf_end; ++ptr)
+        for (auto ptr = buf, buf_end = buf + NUM_CELLS; ptr < buf_end; ++ptr)
            if (!ptr->isZero(*this))
            {
                DB::writeVarUInt(ptr - buf);
@ -334,7 +330,7 @@ public:
        Cell::State::writeText(wb);
        DB::writeText(m_size, wb);

-        for (auto ptr = buf, buf_end = buf + BUFFER_SIZE; ptr < buf_end; ++ptr)
+        for (auto ptr = buf, buf_end = buf + NUM_CELLS; ptr < buf_end; ++ptr)
        {
            if (!ptr->isZero(*this))
            {
@ -393,7 +389,7 @@ public:
        destroyElements();
        m_size = 0;

-        memset(static_cast<void *>(buf), 0, BUFFER_SIZE * sizeof(*buf));
+        memset(static_cast<void *>(buf), 0, NUM_CELLS * sizeof(*buf));
    }

    /// After executing this function, the table can only be destroyed,
@ -405,9 +401,9 @@ public:
        free();
    }

-    size_t getBufferSizeInBytes() const { return BUFFER_SIZE * sizeof(Cell); }
+    size_t getBufferSizeInBytes() const { return NUM_CELLS * sizeof(Cell); }

-    size_t getBufferSizeInCells() const { return BUFFER_SIZE; }
+    size_t getBufferSizeInCells() const { return NUM_CELLS; }

 #ifdef DBMS_HASH_MAP_COUNT_COLLISIONS
    size_t getCollisions() const { return 0; }
--- a/dbms/src/Common/HashTable/Hash.h
+++ b/dbms/src/Common/HashTable/Hash.h
@ -76,7 +76,7 @@ template <typename T, typename Enable = void>
 struct DefaultHash;

 template <typename T>
-struct DefaultHash<T, std::enable_if_t<std::is_arithmetic_v<T>>>
+struct DefaultHash<T, std::enable_if_t<is_arithmetic_v<T>>>
 {
    size_t operator() (T key) const
    {
--- a/dbms/src/Common/HashTable/HashMap.h
+++ b/dbms/src/Common/HashTable/HashMap.h
@ -52,12 +52,13 @@ struct HashMapCell
    HashMapCell(const Key & key_, const State &) : value(key_, NoInitTag()) {}
    HashMapCell(const value_type & value_, const State &) : value(value_) {}

-    const Key & getFirst() const { return value.first; }
-    Mapped & getSecond() { return value.second; }
-    const Mapped & getSecond() const { return value.second; }
-
+    /// Get the key (externally).
+    const Key & getKey() const { return value.first; }
+    Mapped & getMapped() { return value.second; }
+    const Mapped & getMapped() const { return value.second; }
    const value_type & getValue() const { return value; }

+    /// Get the key (internally).
    static const Key & getKey(const value_type & value) { return value.first; }

    bool keyEquals(const Key & key_) const { return value.first == key_; }
@ -110,15 +111,6 @@ struct HashMapCell
    }
 };

-template<typename Key, typename Mapped, typename Hash, typename State>
-ALWAYS_INLINE inline auto lookupResultGetKey(HashMapCell<Key, Mapped, Hash, State> * cell)
-{ return &cell->getFirst(); }
-
-template<typename Key, typename Mapped, typename Hash, typename State>
-ALWAYS_INLINE inline auto lookupResultGetMapped(HashMapCell<Key, Mapped, Hash, State> * cell)
-{ return &cell->getSecond(); }
-
-
 template <typename Key, typename TMapped, typename Hash, typename TState = HashTableNoState>
 struct HashMapCellWithSavedHash : public HashMapCell<Key, TMapped, Hash, TState>
 {
@ -136,15 +128,6 @@ struct HashMapCellWithSavedHash : public HashMapCell<Key, TMapped, Hash, TState>
    size_t getHash(const Hash & /*hash_function*/) const { return saved_hash; }
 };

-template<typename Key, typename Mapped, typename Hash, typename State>
-ALWAYS_INLINE inline auto lookupResultGetKey(HashMapCellWithSavedHash<Key, Mapped, Hash, State> * cell)
-{ return &cell->getFirst(); }
-
-template<typename Key, typename Mapped, typename Hash, typename State>
-ALWAYS_INLINE inline auto lookupResultGetMapped(HashMapCellWithSavedHash<Key, Mapped, Hash, State> * cell)
-{ return &cell->getSecond(); }
-
-
 template <
    typename Key,
    typename Cell,
@ -156,14 +139,9 @@ class HashMapTable : public HashTable<Key, Cell, Hash, Grower, Allocator>
 public:
    using Self = HashMapTable;
    using Base = HashTable<Key, Cell, Hash, Grower, Allocator>;
-
-    using key_type = Key;
-    using value_type = typename Cell::value_type;
-    using mapped_type = typename Cell::Mapped;
-
    using LookupResult = typename Base::LookupResult;

-    using HashTable<Key, Cell, Hash, Grower, Allocator>::HashTable;
+    using Base::Base;

    /// Merge every cell's value of current map into the destination map via emplace.
    ///  Func should have signature void(Mapped & dst, Mapped & src, bool emplaced).
@ -178,8 +156,8 @@ public:
        {
            typename Self::LookupResult res_it;
            bool inserted;
-            that.emplace(it->getFirst(), res_it, inserted, it.getHash());
-            func(*lookupResultGetMapped(res_it), it->getSecond(), inserted);
+            that.emplace(Cell::getKey(it->getValue()), res_it, inserted, it.getHash());
+            func(res_it->getMapped(), it->getMapped(), inserted);
        }
    }

@ -193,11 +171,11 @@ public:
    {
        for (auto it = this->begin(), end = this->end(); it != end; ++it)
        {
-            auto res_it = that.find(it->getFirst(), it.getHash());
+            auto res_it = that.find(Cell::getKey(it->getValue()), it.getHash());
            if (!res_it)
-                func(it->getSecond(), it->getSecond(), false);
+                func(it->getMapped(), it->getMapped(), false);
            else
-                func(*lookupResultGetMapped(res_it), it->getSecond(), true);
+                func(res_it->getMapped(), it->getMapped(), true);
        }
    }

@ -206,7 +184,7 @@ public:
    void forEachValue(Func && func)
    {
        for (auto & v : *this)
-            func(v.getFirst(), v.getSecond());
+            func(v.getKey(), v.getMapped());
    }

    /// Call func(Mapped &) for each hash map element.
@ -214,12 +192,12 @@ public:
    void forEachMapped(Func && func)
    {
        for (auto & v : *this)
-            func(v.getSecond());
+            func(v.getMapped());
    }

-    mapped_type & ALWAYS_INLINE operator[](Key x)
+    typename Cell::Mapped & ALWAYS_INLINE operator[](const Key & x)
    {
-        typename HashMapTable::LookupResult it;
+        LookupResult it;
        bool inserted;
        this->emplace(x, it, inserted);

@ -238,9 +216,9 @@ public:
          *  the compiler can not guess about this, and generates the `load`, `increment`, `store` code.
          */
        if (inserted)
-            new(lookupResultGetMapped(it)) mapped_type();
+            new (&it->getMapped()) typename Cell::Mapped();

-        return *lookupResultGetMapped(it);
+        return it->getMapped();
    }
 };

--- a/dbms/src/Common/HashTable/HashSet.h
+++ b/dbms/src/Common/HashTable/HashSet.h
@ -84,14 +84,6 @@ struct HashSetCellWithSavedHash : public HashTableCell<Key, Hash, TState>
    size_t getHash(const Hash & /*hash_function*/) const { return saved_hash; }
 };

-template<typename Key, typename Hash, typename State>
-ALWAYS_INLINE inline auto lookupResultGetKey(HashSetCellWithSavedHash<Key, Hash, State> * cell)
-{ return &cell->key; }
-
-template<typename Key, typename Hash, typename State>
-ALWAYS_INLINE inline void * lookupResultGetMapped(HashSetCellWithSavedHash<Key, Hash, State> *)
-{ return nullptr; }
-
 template
 <
    typename Key,
--- a/dbms/src/Common/HashTable/HashTable.h
+++ b/dbms/src/Common/HashTable/HashTable.h
@ -78,66 +78,48 @@ void set(T & x) { x = 0; }
 }

 /**
-  * lookupResultGetKey/Mapped -- functions to get key/"mapped" values from the
-  * LookupResult returned by find() and emplace() methods of HashTable.
-  * Must not be called for a null LookupResult.
+  * getKey/Mapped -- methods to get key/"mapped" values from the LookupResult returned by find() and
+  * emplace() methods of HashTable. Must not be called for a null LookupResult.
  *
-  * We don't use iterators for lookup result to avoid creating temporary
-  * objects. Instead, LookupResult is a pointer of some kind. There are global
-  * functions lookupResultGetKey/Mapped, overloaded for this pointer type, that
-  * return pointers to key/"mapped" values. They are implemented as global
-  * functions and not as methods, because they have to be overloaded for POD
-  * types, e.g. in StringHashTable where different components have different
-  * Cell format.
+  * We don't use iterators for lookup result. Instead, LookupResult is a pointer of some kind. There
+  * are methods getKey/Mapped, that return references or values to key/"mapped" values.
  *
-  * Different hash table implementations support this interface to a varying
-  * degree:
+  * Different hash table implementations support this interface to a varying degree:
  *
-  * 1) Hash tables that store neither the key in its original form, nor a
-  *    "mapped" value: FixedHashTable or StringHashTable.
-  *    Neither GetKey nor GetMapped are supported, the only valid operation is
-  *    checking LookupResult for null.
+  * 1) Hash tables that store neither the key in its original form, nor a "mapped" value:
+  *    FixedHashTable or StringHashTable. Neither GetKey nor GetMapped are supported, the only valid
+  *    operation is checking LookupResult for null.
  *
-  * 2) Hash maps that do not store the key, e.g. FixedHashMap or StringHashMap.
-  *    Only GetMapped is supported.
+  * 2) Hash maps that do not store the key, e.g. FixedHashMap or StringHashMap. Only GetMapped is
+  *    supported.
  *
-  * 3) Hash tables that store the key and do not have a "mapped" value, e.g. the
-  *    normal HashTable.
-  *    GetKey returns the key, and GetMapped returns a zero void pointer. This
-  *    simplifies generic code that works with mapped values: it can overload
-  *    on the return type of GetMapped(), and doesn't need other parameters. One
-  *    example is insertSetMapped() function.
+  * 3) Hash tables that store the key and do not have a "mapped" value, e.g. the normal HashTable.
+  *    GetKey returns the key, and GetMapped returns a zero void pointer. This simplifies generic
+  *    code that works with mapped values: it can overload on the return type of GetMapped(), and
+  *    doesn't need other parameters. One example is insertSetMapped() function.
  *
-  * 4) Hash tables that store both the key and the "mapped" value, e.g. HashMap.
-  *    Both GetKey and GetMapped are supported.
+  * 4) Hash tables that store both the key and the "mapped" value, e.g. HashMap. Both GetKey and
+  *    GetMapped are supported.
  *
  * The implementation side goes as follows:
-  * for (1), LookupResult = void *, no getters;
-  * for (2), LookupResult = Mapped *, GetMapped is a default implementation that
-  * takes any pointer-like object;
-  * for (3) and (4), LookupResult = Cell *, and both getters are implemented.
-  * They have to be specialized for each particular Cell class to supersede the
-  * default verision that takes a generic pointer-like object.
+  *
+  * for (1), LookupResult->getKey = const VoidKey, LookupResult->getMapped = VoidMapped;
+  *
+  * for (2), LookupResult->getKey = const VoidKey, LookupResult->getMapped = Mapped &;
+  *
+  * for (3) and (4), LookupResult->getKey = const Key [&], LookupResult->getMapped = Mapped &;
+  * VoidKey and VoidMapped may have specialized function overloads for generic code.
  */

-/**
-  * The default implementation of GetMapped that is used for the above case (2).
-  */
-template<typename PointerLike>
-ALWAYS_INLINE inline auto lookupResultGetMapped(PointerLike && ptr) { return &*ptr; }
-
-/**
-  * Generic const wrapper for lookupResultGetMapped, that calls a non-const
-  * version. Should be safe, given that these functions only do pointer
-  * arithmetics.
-  */
-template<typename T>
-ALWAYS_INLINE inline auto lookupResultGetMapped(const T * obj)
+struct VoidKey {};
+struct VoidMapped
 {
-    auto mapped_ptr = lookupResultGetMapped(const_cast<T *>(obj));
-    const auto const_mapped_ptr = mapped_ptr;
-    return const_mapped_ptr;
-}
+    template <typename T>
+    auto & operator=(const T &)
+    {
+        return *this;
+    }
+};

 /** Compile-time interface for cell of the hash table.
  * Different cell types are used to implement different hash tables.
@ -152,7 +134,7 @@ struct HashTableCell

    using key_type = Key;
    using value_type = Key;
-    using mapped_type = void;
+    using mapped_type = VoidMapped;

    Key key;

@ -161,10 +143,12 @@ struct HashTableCell
    /// Create a cell with the given key / key and value.
    HashTableCell(const Key & key_, const State &) : key(key_) {}

-    /// Get what the value_type of the container will be.
+    /// Get the key (externally).
+    const Key & getKey() const { return key; }
+    VoidMapped getMapped() const { return {}; }
    const value_type & getValue() const { return key; }

-    /// Get the key.
+    /// Get the key (internally).
    static const Key & getKey(const value_type & value) { return value; }

    /// Are the keys at the cells equal?
@ -207,23 +191,15 @@ struct HashTableCell
    void readText(DB::ReadBuffer & rb)    { DB::readDoubleQuoted(key, rb); }
 };

-template<typename Key, typename Hash, typename State>
-ALWAYS_INLINE inline auto lookupResultGetKey(HashTableCell<Key, Hash, State> * cell)
-{ return &cell->key; }
-
-template<typename Key, typename Hash, typename State>
-ALWAYS_INLINE inline void * lookupResultGetMapped(HashTableCell<Key, Hash, State> *)
-{ return nullptr; }
-
 /**
  * A helper function for HashTable::insert() to set the "mapped" value.
-  * Overloaded on the mapped type, does nothing if it's void.
+  * Overloaded on the mapped type, does nothing if it's VoidMapped.
  */
 template <typename ValueType>
-void insertSetMapped(void * /* dest */, const ValueType & /* src */) {}
+void insertSetMapped(VoidMapped /* dest */, const ValueType & /* src */) {}

 template <typename MappedType, typename ValueType>
-void insertSetMapped(MappedType * dest, const ValueType & src) { *dest = src.second; }
+void insertSetMapped(MappedType & dest, const ValueType & src) { dest = src.second; }


 /** Determines the size of the hash table, and when and how much it should be resized.
@ -276,7 +252,7 @@ struct HashTableGrower
 /** When used as a Grower, it turns a hash table into something like a lookup table.
  * It remains non-optimal - the cells store the keys.
  * Also, the compiler can not completely remove the code of passing through the collision resolution chain, although it is not needed.
-  * TODO Make a proper lookup table.
+  * NOTE: Better to use FixedHashTable instead.
  */
 template <size_t key_bits>
 struct HashTableFixedGrower
@ -358,9 +334,14 @@ protected:
    template <typename, typename, typename, typename, typename, typename, size_t>
    friend class TwoLevelHashTable;

+    template <typename, typename, size_t>
+    friend class TwoLevelStringHashTable;
+
+    template <typename SubMaps>
+    friend class StringHashTable;
+
    using HashValue = size_t;
    using Self = HashTable;
-    using cell_type = Cell;

    size_t m_size = 0;        /// Amount of elements
    Cell * buf;               /// A piece of memory for all elements except the element with zero key.
@ -580,9 +561,10 @@ protected:

 public:
    using key_type = Key;
+    using mapped_type = typename Cell::mapped_type;
    using value_type = typename Cell::value_type;
+    using cell_type = Cell;

-    // Use lookupResultGetMapped/Key to work with these values.
    using LookupResult = Cell *;
    using ConstLookupResult = const Cell *;

@ -745,7 +727,7 @@ protected:
    /// If the key is zero, insert it into a special place and return true.
    /// We don't have to persist a zero key, because it's not actually inserted.
    /// That's why we just take a Key by value, an not a key holder.
-    bool ALWAYS_INLINE emplaceIfZero(Key x, LookupResult & it, bool & inserted, size_t hash_value)
+    bool ALWAYS_INLINE emplaceIfZero(const Key & x, LookupResult & it, bool & inserted, size_t hash_value)
    {
        /// If it is claimed that the zero key can not be inserted into the table.
        if (!Cell::need_zero_value_storage)
@ -787,7 +769,7 @@ protected:
        keyHolderPersistKey(key_holder);
        const auto & key = keyHolderGetKey(key_holder);

-        new(&buf[place_value]) Cell(key, *this);
+        new (&buf[place_value]) Cell(key, *this);
        buf[place_value].setHash(hash_value);
        inserted = true;
        ++m_size;
@ -840,7 +822,7 @@ public:
        }

        if (res.second)
-            insertSetMapped(lookupResultGetMapped(res.first), x);
+            insertSetMapped(res.first->getMapped(), x);

        return res;
    }
@ -863,11 +845,11 @@ public:
      *
      * Example usage:
      *
-      * Map::iterator it;
+      * Map::LookupResult it;
      * bool inserted;
      * map.emplace(key, it, inserted);
      * if (inserted)
-      *     new(&it->second) Mapped(value);
+      *     new (&it->getMapped()) Mapped(value);
      */
    template <typename KeyHolder>
    void ALWAYS_INLINE emplace(KeyHolder && key_holder, LookupResult & it, bool & inserted)
@ -897,7 +879,7 @@ public:
            resize();
    }

-    LookupResult ALWAYS_INLINE find(Key x)
+    LookupResult ALWAYS_INLINE find(const Key & x)
    {
        if (Cell::isZero(x, *this))
            return this->hasZero() ? this->zeroValue() : nullptr;
@ -907,12 +889,12 @@ public:
        return !buf[place_value].isZero(*this) ? &buf[place_value] : nullptr;
    }

-    ConstLookupResult ALWAYS_INLINE find(Key x) const
+    ConstLookupResult ALWAYS_INLINE find(const Key & x) const
    {
        return const_cast<std::decay_t<decltype(*this)> *>(this)->find(x);
    }

-    LookupResult ALWAYS_INLINE find(Key x, size_t hash_value)
+    LookupResult ALWAYS_INLINE find(const Key & x, size_t hash_value)
    {
        if (Cell::isZero(x, *this))
            return this->hasZero() ? this->zeroValue() : nullptr;
@ -921,7 +903,12 @@ public:
        return !buf[place_value].isZero(*this) ? &buf[place_value] : nullptr;
    }

-    bool ALWAYS_INLINE has(Key x) const
+    ConstLookupResult ALWAYS_INLINE find(const Key & x, size_t hash_value) const
+    {
+        return const_cast<std::decay_t<decltype(*this)> *>(this)->find(x, hash_value);
+    }
+
+    bool ALWAYS_INLINE has(const Key & x) const
    {
        if (Cell::isZero(x, *this))
            return this->hasZero();
@ -932,7 +919,7 @@ public:
    }


-    bool ALWAYS_INLINE has(Key x, size_t hash_value) const
+    bool ALWAYS_INLINE has(const Key & x, size_t hash_value) const
    {
        if (Cell::isZero(x, *this))
            return this->hasZero();
--- a/dbms/src/Common/HashTable/SmallTable.h
+++ b/dbms/src/Common/HashTable/SmallTable.h
@ -38,7 +38,6 @@ protected:
    friend class Reader;

    using Self = SmallTable;
-    using cell_type = Cell;

    size_t m_size = 0;        /// Amount of elements.
    Cell buf[capacity];       /// A piece of memory for all elements.
@ -72,8 +71,9 @@ protected:

 public:
    using key_type = Key;
+    using mapped_type = typename Cell::mapped_type;
    using value_type = typename Cell::value_type;
-
+    using cell_type = Cell;

    class Reader final : private Cell::State
    {
@ -391,16 +391,17 @@ class SmallMapTable : public SmallTable<Key, Cell, capacity>
 {
 public:
    using key_type = Key;
-    using mapped_type = typename Cell::Mapped;
+    using mapped_type = typename Cell::mapped_type;
    using value_type = typename Cell::value_type;
+    using cell_type = Cell;

    mapped_type & ALWAYS_INLINE operator[](Key x)
    {
        typename SmallMapTable::iterator it;
        bool inserted;
        this->emplace(x, it, inserted);
-        new(&it->getSecond()) mapped_type();
-        return it->getSecond();
+        new (&it->getMapped()) mapped_type();
+        return it->getMapped();
    }
 };

--- a/dbms/src/Common/HashTable/StringHashMap.h
+++ b/dbms/src/Common/HashTable/StringHashMap.h
@ -0,0 +1,182 @@
+#pragma once
+
+#include <Common/HashTable/HashMap.h>
+#include <Common/HashTable/HashTableAllocator.h>
+#include <Common/HashTable/StringHashTable.h>
+
+template <typename Key, typename TMapped>
+struct StringHashMapCell : public HashMapCell<Key, TMapped, StringHashTableHash, HashTableNoState>
+{
+    using Base = HashMapCell<Key, TMapped, StringHashTableHash, HashTableNoState>;
+    using value_type = typename Base::value_type;
+    using Base::Base;
+    static constexpr bool need_zero_value_storage = false;
+    // external
+    const StringRef getKey() const { return toStringRef(this->value.first); }
+    // internal
+    static const Key & getKey(const value_type & value_) { return value_.first; }
+};
+
+template <typename TMapped>
+struct StringHashMapCell<StringKey16, TMapped> : public HashMapCell<StringKey16, TMapped, StringHashTableHash, HashTableNoState>
+{
+    using Base = HashMapCell<StringKey16, TMapped, StringHashTableHash, HashTableNoState>;
+    using value_type = typename Base::value_type;
+    using Base::Base;
+    static constexpr bool need_zero_value_storage = false;
+    bool isZero(const HashTableNoState & state) const { return isZero(this->value.first, state); }
+    // Assuming String does not contain zero bytes. NOTE: Cannot be used in serialized method
+    static bool isZero(const StringKey16 & key, const HashTableNoState & /*state*/) { return key.low == 0; }
+    void setZero() { this->value.first.low = 0; }
+    // external
+    const StringRef getKey() const { return toStringRef(this->value.first); }
+    // internal
+    static const StringKey16 & getKey(const value_type & value_) { return value_.first; }
+};
+
+template <typename TMapped>
+struct StringHashMapCell<StringKey24, TMapped> : public HashMapCell<StringKey24, TMapped, StringHashTableHash, HashTableNoState>
+{
+    using Base = HashMapCell<StringKey24, TMapped, StringHashTableHash, HashTableNoState>;
+    using value_type = typename Base::value_type;
+    using Base::Base;
+    static constexpr bool need_zero_value_storage = false;
+    bool isZero(const HashTableNoState & state) const { return isZero(this->value.first, state); }
+    // Assuming String does not contain zero bytes. NOTE: Cannot be used in serialized method
+    static bool isZero(const StringKey24 & key, const HashTableNoState & /*state*/) { return key.a == 0; }
+    void setZero() { this->value.first.a = 0; }
+    // external
+    const StringRef getKey() const { return toStringRef(this->value.first); }
+    // internal
+    static const StringKey24 & getKey(const value_type & value_) { return value_.first; }
+};
+
+template <typename TMapped>
+struct StringHashMapCell<StringRef, TMapped> : public HashMapCellWithSavedHash<StringRef, TMapped, StringHashTableHash, HashTableNoState>
+{
+    using Base = HashMapCellWithSavedHash<StringRef, TMapped, StringHashTableHash, HashTableNoState>;
+    using value_type = typename Base::value_type;
+    using Base::Base;
+    static constexpr bool need_zero_value_storage = false;
+    // external
+    using Base::getKey;
+    // internal
+    static const StringRef & getKey(const value_type & value_) { return value_.first; }
+};
+
+template <typename TMapped, typename Allocator>
+struct StringHashMapSubMaps
+{
+    using T0 = StringHashTableEmpty<StringHashMapCell<StringRef, TMapped>>;
+    using T1 = HashMapTable<StringKey8, StringHashMapCell<StringKey8, TMapped>, StringHashTableHash, StringHashTableGrower<>, Allocator>;
+    using T2 = HashMapTable<StringKey16, StringHashMapCell<StringKey16, TMapped>, StringHashTableHash, StringHashTableGrower<>, Allocator>;
+    using T3 = HashMapTable<StringKey24, StringHashMapCell<StringKey24, TMapped>, StringHashTableHash, StringHashTableGrower<>, Allocator>;
+    using Ts = HashMapTable<StringRef, StringHashMapCell<StringRef, TMapped>, StringHashTableHash, StringHashTableGrower<>, Allocator>;
+};
+
+template <typename TMapped, typename Allocator = HashTableAllocator>
+class StringHashMap : public StringHashTable<StringHashMapSubMaps<TMapped, Allocator>>
+{
+public:
+    using Key = StringRef;
+    using Base = StringHashTable<StringHashMapSubMaps<TMapped, Allocator>>;
+    using Self = StringHashMap;
+    using LookupResult = typename Base::LookupResult;
+
+    using Base::Base;
+
+    /// Merge every cell's value of current map into the destination map.
+    ///  Func should have signature void(Mapped & dst, Mapped & src, bool emplaced).
+    ///  Each filled cell in current map will invoke func once. If that map doesn't
+    ///  have a key equals to the given cell, a new cell gets emplaced into that map,
+    ///  and func is invoked with the third argument emplaced set to true. Otherwise
+    ///  emplaced is set to false.
+    template <typename Func>
+    void ALWAYS_INLINE mergeToViaEmplace(Self & that, Func && func)
+    {
+        if (this->m0.hasZero() && that.m0.hasZero())
+            func(that.m0.zeroValue()->getMapped(), this->m0.zeroValue()->getMapped(), false);
+        else if (this->m0.hasZero())
+        {
+            that.m0.setHasZero();
+            func(that.m0.zeroValue()->getMapped(), this->m0.zeroValue()->getMapped(), true);
+        }
+        this->m1.mergeToViaEmplace(that.m1, func);
+        this->m2.mergeToViaEmplace(that.m2, func);
+        this->m3.mergeToViaEmplace(that.m3, func);
+        this->ms.mergeToViaEmplace(that.ms, func);
+    }
+
+    /// Merge every cell's value of current map into the destination map via find.
+    ///  Func should have signature void(Mapped & dst, Mapped & src, bool exist).
+    ///  Each filled cell in current map will invoke func once. If that map doesn't
+    ///  have a key equals to the given cell, func is invoked with the third argument
+    ///  exist set to false. Otherwise exist is set to true.
+    template <typename Func>
+    void ALWAYS_INLINE mergeToViaFind(Self & that, Func && func)
+    {
+        if (this->m0.size() && that.m0.size())
+            func(that.m0.zeroValue()->getMapped(), this->m0.zeroValue()->getMapped(), true);
+        else if (this->m0.size())
+            func(this->m0.zeroValue()->getMapped(), this->m0.zeroValue()->getMapped(), false);
+        this->m1.mergeToViaFind(that.m1, func);
+        this->m2.mergeToViaFind(that.m2, func);
+        this->m3.mergeToViaFind(that.m3, func);
+        this->ms.mergeToViaFind(that.ms, func);
+    }
+
+    TMapped & ALWAYS_INLINE operator[](const Key & x)
+    {
+        LookupResult it;
+        bool inserted;
+        this->emplace(x, it, inserted);
+        if (inserted)
+            new (&it->getMapped()) TMapped();
+
+        return it->getMapped();
+    }
+
+    template <typename Func>
+    void ALWAYS_INLINE forEachValue(Func && func)
+    {
+        if (this->m0.size())
+        {
+            func(StringRef{}, this->m0.zeroValue()->getMapped());
+        }
+
+        for (auto & v : this->m1)
+        {
+            func(v.getKey(), v.getMapped());
+        }
+
+        for (auto & v : this->m2)
+        {
+            func(v.getKey(), v.getMapped());
+        }
+
+        for (auto & v : this->m3)
+        {
+            func(v.getKey(), v.getMapped());
+        }
+
+        for (auto & v : this->ms)
+        {
+            func(v.getKey(), v.getMapped());
+        }
+    }
+
+    template <typename Func>
+    void ALWAYS_INLINE forEachMapped(Func && func)
+    {
+        if (this->m0.size())
+            func(this->m0.zeroValue()->getMapped());
+        for (auto & v : this->m1)
+            func(v.getMapped());
+        for (auto & v : this->m2)
+            func(v.getMapped());
+        for (auto & v : this->m3)
+            func(v.getMapped());
+        for (auto & v : this->ms)
+            func(v.getMapped());
+    }
+};
--- a/dbms/src/Common/HashTable/StringHashTable.h
+++ b/dbms/src/Common/HashTable/StringHashTable.h
@ -0,0 +1,407 @@
+#pragma once
+
+#include <Common/HashTable/HashMap.h>
+#include <Common/HashTable/HashTable.h>
+
+#include <variant>
+
+using StringKey8 = UInt64;
+using StringKey16 = DB::UInt128;
+struct StringKey24
+{
+    UInt64 a;
+    UInt64 b;
+    UInt64 c;
+
+    bool operator==(const StringKey24 rhs) const { return a == rhs.a && b == rhs.b && c == rhs.c; }
+};
+
+inline StringRef ALWAYS_INLINE toStringRef(const StringKey8 & n)
+{
+    return {reinterpret_cast<const char *>(&n), 8ul - (__builtin_clzll(n) >> 3)};
+}
+inline StringRef ALWAYS_INLINE toStringRef(const StringKey16 & n)
+{
+    return {reinterpret_cast<const char *>(&n), 16ul - (__builtin_clzll(n.high) >> 3)};
+}
+inline StringRef ALWAYS_INLINE toStringRef(const StringKey24 & n)
+{
+    return {reinterpret_cast<const char *>(&n), 24ul - (__builtin_clzll(n.c) >> 3)};
+}
+
+struct StringHashTableHash
+{
+#if defined(__SSE4_2__)
+    size_t ALWAYS_INLINE operator()(StringKey8 key) const
+    {
+        size_t res = -1ULL;
+        res = _mm_crc32_u64(res, key);
+        return res;
+    }
+    size_t ALWAYS_INLINE operator()(StringKey16 key) const
+    {
+        size_t res = -1ULL;
+        res = _mm_crc32_u64(res, key.low);
+        res = _mm_crc32_u64(res, key.high);
+        return res;
+    }
+    size_t ALWAYS_INLINE operator()(StringKey24 key) const
+    {
+        size_t res = -1ULL;
+        res = _mm_crc32_u64(res, key.a);
+        res = _mm_crc32_u64(res, key.b);
+        res = _mm_crc32_u64(res, key.c);
+        return res;
+    }
+#else
+    size_t ALWAYS_INLINE operator()(StringKey8 key) const
+    {
+        return CityHash_v1_0_2::CityHash64(reinterpret_cast<const char *>(&key), 8);
+    }
+    size_t ALWAYS_INLINE operator()(StringKey16 key) const
+    {
+        return CityHash_v1_0_2::CityHash64(reinterpret_cast<const char *>(&key), 16);
+    }
+    size_t ALWAYS_INLINE operator()(StringKey24 key) const
+    {
+        return CityHash_v1_0_2::CityHash64(reinterpret_cast<const char *>(&key), 24);
+    }
+#endif
+    size_t ALWAYS_INLINE operator()(StringRef key) const
+    {
+        return StringRefHash()(key);
+    }
+};
+
+template <typename Cell>
+struct StringHashTableEmpty
+{
+    using Self = StringHashTableEmpty;
+
+    bool has_zero = false;
+    std::aligned_storage_t<sizeof(Cell), alignof(Cell)> zero_value_storage; /// Storage of element with zero key.
+
+public:
+    bool hasZero() const { return has_zero; }
+
+    void setHasZero()
+    {
+        has_zero = true;
+        new (zeroValue()) Cell();
+    }
+
+    void setHasZero(const Cell & other)
+    {
+        has_zero = true;
+        new (zeroValue()) Cell(other);
+    }
+
+    void clearHasZero()
+    {
+        has_zero = false;
+        if (!std::is_trivially_destructible_v<Cell>)
+            zeroValue()->~Cell();
+    }
+
+    Cell * zeroValue() { return reinterpret_cast<Cell *>(&zero_value_storage); }
+    const Cell * zeroValue() const { return reinterpret_cast<const Cell *>(&zero_value_storage); }
+
+    using LookupResult = Cell *;
+    using ConstLookupResult = const Cell *;
+
+    template <typename KeyHolder>
+    void ALWAYS_INLINE emplace(KeyHolder &&, LookupResult & it, bool & inserted, size_t = 0)
+    {
+        if (!hasZero())
+        {
+            setHasZero();
+            inserted = true;
+        }
+        else
+            inserted = false;
+        it = zeroValue();
+    }
+
+    template <typename Key>
+    LookupResult ALWAYS_INLINE find(const Key &, size_t = 0)
+    {
+        return hasZero() ? zeroValue() : nullptr;
+    }
+
+    template <typename Key>
+    ConstLookupResult ALWAYS_INLINE find(const Key &, size_t = 0) const
+    {
+        return hasZero() ? zeroValue() : nullptr;
+    }
+
+    void write(DB::WriteBuffer & wb) const { zeroValue()->write(wb); }
+    void writeText(DB::WriteBuffer & wb) const { zeroValue()->writeText(wb); }
+    void read(DB::ReadBuffer & rb) { zeroValue()->read(rb); }
+    void readText(DB::ReadBuffer & rb) { zeroValue()->readText(rb); }
+    size_t size() const { return hasZero() ? 1 : 0; }
+    bool empty() const { return !hasZero(); }
+    size_t getBufferSizeInBytes() const { return sizeof(Cell); }
+    size_t getCollisions() const { return 0; }
+};
+
+template <size_t initial_size_degree = 8>
+struct StringHashTableGrower : public HashTableGrower<initial_size_degree>
+{
+    // Smooth growing for string maps
+    void increaseSize() { this->size_degree += 1; }
+};
+
+template <typename Mapped>
+struct StringHashTableLookupResult
+{
+    Mapped * mapped_ptr;
+    StringHashTableLookupResult() {}
+    StringHashTableLookupResult(Mapped * mapped_ptr_) : mapped_ptr(mapped_ptr_) {}
+    StringHashTableLookupResult(std::nullptr_t) {}
+    const VoidKey getKey() const { return {}; }
+    auto & getMapped() { return *mapped_ptr; }
+    auto & operator*() { return *this; }
+    auto & operator*() const { return *this; }
+    auto * operator->() { return this; }
+    auto * operator->() const { return this; }
+    operator bool() const { return mapped_ptr; }
+    friend bool operator==(const StringHashTableLookupResult & a, const std::nullptr_t &) { return !a.mapped_ptr; }
+    friend bool operator==(const std::nullptr_t &, const StringHashTableLookupResult & b) { return !b.mapped_ptr; }
+    friend bool operator!=(const StringHashTableLookupResult & a, const std::nullptr_t &) { return a.mapped_ptr; }
+    friend bool operator!=(const std::nullptr_t &, const StringHashTableLookupResult & b) { return b.mapped_ptr; }
+};
+
+template <typename SubMaps>
+class StringHashTable : private boost::noncopyable
+{
+protected:
+    static constexpr size_t NUM_MAPS = 5;
+    // Map for storing empty string
+    using T0 = typename SubMaps::T0;
+
+    // Short strings are stored as numbers
+    using T1 = typename SubMaps::T1;
+    using T2 = typename SubMaps::T2;
+    using T3 = typename SubMaps::T3;
+
+    // Long strings are stored as StringRef along with saved hash
+    using Ts = typename SubMaps::Ts;
+    using Self = StringHashTable;
+
+    template <typename, typename, size_t>
+    friend class TwoLevelStringHashTable;
+
+    T0 m0;
+    T1 m1;
+    T2 m2;
+    T3 m3;
+    Ts ms;
+
+public:
+    using Key = StringRef;
+    using key_type = Key;
+    using mapped_type = typename Ts::mapped_type;
+    using value_type = typename Ts::value_type;
+    using cell_type = typename Ts::cell_type;
+
+    using LookupResult = StringHashTableLookupResult<typename cell_type::mapped_type>;
+    using ConstLookupResult = StringHashTableLookupResult<const typename cell_type::mapped_type>;
+
+    StringHashTable() {}
+
+    StringHashTable(size_t reserve_for_num_elements)
+        : m1{reserve_for_num_elements / 4}
+        , m2{reserve_for_num_elements / 4}
+        , m3{reserve_for_num_elements / 4}
+        , ms{reserve_for_num_elements / 4}
+    {
+    }
+
+    StringHashTable(StringHashTable && rhs) { *this = std::move(rhs); }
+    ~StringHashTable() {}
+
+public:
+    // Dispatch is written in a way that maximizes the performance:
+    // 1. Always memcpy 8 times bytes
+    // 2. Use switch case extension to generate fast dispatching table
+    // 3. Funcs are named callables that can be force_inlined
+    // NOTE: It relies on Little Endianness
+    template <typename Self, typename KeyHolder, typename Func>
+    static auto ALWAYS_INLINE dispatch(Self & self, KeyHolder && key_holder, Func && func)
+    {
+        const StringRef & x = keyHolderGetKey(key_holder);
+        const size_t sz = x.size;
+        if (sz == 0)
+        {
+            keyHolderDiscardKey(key_holder);
+            return func(self.m0, VoidKey{}, 0);
+        }
+
+        const char * p = x.data;
+        // pending bits that needs to be shifted out
+        const char s = (-sz & 7) * 8;
+        union
+        {
+            StringKey8 k8;
+            StringKey16 k16;
+            StringKey24 k24;
+            UInt64 n[3];
+        };
+        StringHashTableHash hash;
+        switch ((sz - 1) >> 3)
+        {
+            case 0: // 1..8 bytes
+            {
+                // first half page
+                if ((reinterpret_cast<uintptr_t>(p) & 2048) == 0)
+                {
+                    memcpy(&n[0], p, 8);
+                    n[0] &= -1ul >> s;
+                }
+                else
+                {
+                    const char * lp = x.data + x.size - 8;
+                    memcpy(&n[0], lp, 8);
+                    n[0] >>= s;
+                }
+                keyHolderDiscardKey(key_holder);
+                return func(self.m1, k8, hash(k8));
+            }
+            case 1: // 9..16 bytes
+            {
+                memcpy(&n[0], p, 8);
+                const char * lp = x.data + x.size - 8;
+                memcpy(&n[1], lp, 8);
+                n[1] >>= s;
+                keyHolderDiscardKey(key_holder);
+                return func(self.m2, k16, hash(k16));
+            }
+            case 2: // 17..24 bytes
+            {
+                memcpy(&n[0], p, 16);
+                const char * lp = x.data + x.size - 8;
+                memcpy(&n[2], lp, 8);
+                n[2] >>= s;
+                keyHolderDiscardKey(key_holder);
+                return func(self.m3, k24, hash(k24));
+            }
+            default: // >= 25 bytes
+            {
+                return func(self.ms, std::forward<KeyHolder>(key_holder), hash(x));
+            }
+        }
+    }
+
+    struct EmplaceCallable
+    {
+        LookupResult & mapped;
+        bool & inserted;
+
+        EmplaceCallable(LookupResult & mapped_, bool & inserted_)
+            : mapped(mapped_), inserted(inserted_) {}
+
+        template <typename Map, typename KeyHolder>
+        void ALWAYS_INLINE operator()(Map & map, KeyHolder && key_holder, size_t hash)
+        {
+            typename Map::LookupResult result;
+            map.emplace(key_holder, result, inserted, hash);
+            mapped = &result->getMapped();
+        }
+    };
+
+    template <typename KeyHolder>
+    void ALWAYS_INLINE emplace(KeyHolder && key_holder, LookupResult & it, bool & inserted)
+    {
+        this->dispatch(*this, key_holder, EmplaceCallable(it, inserted));
+    }
+
+    struct FindCallable
+    {
+        // find() doesn't need any key memory management, so we don't work with
+        // any key holders here, only with normal keys. The key type is still
+        // different for every subtable, this is why it is a template parameter.
+        template <typename Submap, typename SubmapKey>
+        auto ALWAYS_INLINE operator()(Submap & map, const SubmapKey & key, size_t hash)
+        {
+            return &map.find(key, hash)->getMapped();
+        }
+    };
+
+    LookupResult ALWAYS_INLINE find(const Key & x)
+    {
+        return dispatch(*this, x, FindCallable{});
+    }
+
+    ConstLookupResult ALWAYS_INLINE find(const Key & x) const
+    {
+        return dispatch(*this, x, FindCallable{});
+    }
+
+    bool ALWAYS_INLINE has(const Key & x, size_t = 0) const
+    {
+        return dispatch(*this, x, FindCallable{}) != nullptr;
+    }
+
+    void write(DB::WriteBuffer & wb) const
+    {
+        m0.write(wb);
+        m1.write(wb);
+        m2.write(wb);
+        m3.write(wb);
+        ms.write(wb);
+    }
+
+    void writeText(DB::WriteBuffer & wb) const
+    {
+        m0.writeText(wb);
+        DB::writeChar(',', wb);
+        m1.writeText(wb);
+        DB::writeChar(',', wb);
+        m2.writeText(wb);
+        DB::writeChar(',', wb);
+        m3.writeText(wb);
+        DB::writeChar(',', wb);
+        ms.writeText(wb);
+    }
+
+    void read(DB::ReadBuffer & rb)
+    {
+        m0.read(rb);
+        m1.read(rb);
+        m2.read(rb);
+        m3.read(rb);
+        ms.read(rb);
+    }
+
+    void readText(DB::ReadBuffer & rb)
+    {
+        m0.readText(rb);
+        DB::assertChar(',', rb);
+        m1.readText(rb);
+        DB::assertChar(',', rb);
+        m2.readText(rb);
+        DB::assertChar(',', rb);
+        m3.readText(rb);
+        DB::assertChar(',', rb);
+        ms.readText(rb);
+    }
+
+    size_t size() const { return m0.size() + m1.size() + m2.size() + m3.size() + ms.size(); }
+
+    bool empty() const { return m0.empty() && m1.empty() && m2.empty() && m3.empty() && ms.empty(); }
+
+    size_t getBufferSizeInBytes() const
+    {
+        return m0.getBufferSizeInBytes() + m1.getBufferSizeInBytes() + m2.getBufferSizeInBytes() + m3.getBufferSizeInBytes()
+            + ms.getBufferSizeInBytes();
+    }
+
+    void clearAndShrink()
+    {
+        m1.clearHasZero();
+        m1.clearAndShrink();
+        m2.clearAndShrink();
+        m3.clearAndShrink();
+        ms.clearAndShrink();
+    }
+};
--- a/dbms/src/Common/HashTable/TwoLevelHashMap.h
+++ b/dbms/src/Common/HashTable/TwoLevelHashMap.h
@ -16,10 +16,6 @@ template
 class TwoLevelHashMapTable : public TwoLevelHashTable<Key, Cell, Hash, Grower, Allocator, ImplTable<Key, Cell, Hash, Grower, Allocator>>
 {
 public:
-    using key_type = Key;
-    using mapped_type = typename Cell::Mapped;
-    using value_type = typename Cell::value_type;
-
    using Impl = ImplTable<Key, Cell, Hash, Grower, Allocator>;
    using LookupResult = typename Impl::LookupResult;

@ -32,16 +28,16 @@ public:
            this->impls[i].forEachMapped(func);
    }

-    mapped_type & ALWAYS_INLINE operator[](Key x)
+    typename Cell::Mapped & ALWAYS_INLINE operator[](const Key & x)
    {
-        typename TwoLevelHashMapTable::LookupResult it;
+        LookupResult it;
        bool inserted;
        this->emplace(x, it, inserted);

        if (inserted)
-            new(lookupResultGetMapped(it)) mapped_type();
+            new (&it->getMapped()) typename Cell::Mapped();

-        return *lookupResultGetMapped(it);
+        return it->getMapped();
    }
 };

--- a/dbms/src/Common/HashTable/TwoLevelHashTable.h
+++ b/dbms/src/Common/HashTable/TwoLevelHashTable.h
@ -82,7 +82,9 @@ protected:

 public:
    using key_type = typename Impl::key_type;
+    using mapped_type = typename Impl::mapped_type;
    using value_type = typename Impl::value_type;
+    using cell_type = typename Impl::cell_type;

    using LookupResult = typename Impl::LookupResult;
    using ConstLookupResult = typename Impl::ConstLookupResult;
@ -217,7 +219,7 @@ public:
        emplace(Cell::getKey(x), res.first, res.second, hash_value);

        if (res.second)
-            insertSetMapped(lookupResultGetMapped(res.first), x);
+            insertSetMapped(res.first->getMapped(), x);

        return res;
    }
--- a/dbms/src/Common/HashTable/TwoLevelStringHashMap.h
+++ b/dbms/src/Common/HashTable/TwoLevelStringHashMap.h
@ -0,0 +1,33 @@
+#pragma once
+
+#include <Common/HashTable/StringHashMap.h>
+#include <Common/HashTable/TwoLevelStringHashTable.h>
+
+template <typename TMapped, typename Allocator = HashTableAllocator, template <typename...> typename ImplTable = StringHashMap>
+class TwoLevelStringHashMap : public TwoLevelStringHashTable<StringHashMapSubMaps<TMapped, Allocator>, ImplTable<TMapped, Allocator>>
+{
+public:
+    using Key = StringRef;
+    using Self = TwoLevelStringHashMap;
+    using Base = TwoLevelStringHashTable<StringHashMapSubMaps<TMapped, Allocator>, StringHashMap<TMapped, Allocator>>;
+    using LookupResult = typename Base::LookupResult;
+
+    using Base::Base;
+
+    template <typename Func>
+    void ALWAYS_INLINE forEachMapped(Func && func)
+    {
+        for (auto i = 0u; i < this->NUM_BUCKETS; ++i)
+            return this->impls[i].forEachMapped(func);
+    }
+
+    TMapped & ALWAYS_INLINE operator[](const Key & x)
+    {
+        bool inserted;
+        LookupResult it;
+        this->emplace(x, it, inserted);
+        if (inserted)
+            new (&it->getMapped()) TMapped();
+        return it->getMapped();
+    }
+};
--- a/dbms/src/Common/HashTable/TwoLevelStringHashTable.h
+++ b/dbms/src/Common/HashTable/TwoLevelStringHashTable.h
@ -0,0 +1,225 @@
+#pragma once
+
+#include <Common/HashTable/StringHashTable.h>
+
+template <typename SubMaps, typename ImplTable = StringHashTable<SubMaps>, size_t BITS_FOR_BUCKET = 8>
+class TwoLevelStringHashTable : private boost::noncopyable
+{
+protected:
+    using HashValue = size_t;
+    using Self = TwoLevelStringHashTable;
+
+public:
+    using Key = StringRef;
+    using Impl = ImplTable;
+
+    static constexpr size_t NUM_BUCKETS = 1ULL << BITS_FOR_BUCKET;
+    static constexpr size_t MAX_BUCKET = NUM_BUCKETS - 1;
+
+    // TODO: currently hashing contains redundant computations when doing distributed or external aggregations
+    size_t hash(const Key & x) const
+    {
+        return const_cast<Self &>(*this).dispatch(*this, x, [&](const auto &, const auto &, size_t hash) { return hash; });
+    }
+
+    size_t operator()(const Key & x) const { return hash(x); }
+
+    /// NOTE Bad for hash tables with more than 2^32 cells.
+    static size_t getBucketFromHash(size_t hash_value) { return (hash_value >> (32 - BITS_FOR_BUCKET)) & MAX_BUCKET; }
+
+public:
+    using key_type = typename Impl::key_type;
+    using mapped_type = typename Impl::mapped_type;
+    using value_type = typename Impl::value_type;
+    using cell_type = typename Impl::cell_type;
+
+    using LookupResult = typename Impl::LookupResult;
+    using ConstLookupResult = typename Impl::ConstLookupResult;
+
+    Impl impls[NUM_BUCKETS];
+
+    TwoLevelStringHashTable() {}
+
+    template <typename Source>
+    TwoLevelStringHashTable(const Source & src)
+    {
+        if (src.m0.hasZero())
+            impls[0].m0.setHasZero(*src.m0.zeroValue());
+
+        for (auto & v : src.m1)
+        {
+            size_t hash_value = v.getHash(src.m1);
+            size_t buck = getBucketFromHash(hash_value);
+            impls[buck].m1.insertUniqueNonZero(&v, hash_value);
+        }
+        for (auto & v : src.m2)
+        {
+            size_t hash_value = v.getHash(src.m2);
+            size_t buck = getBucketFromHash(hash_value);
+            impls[buck].m2.insertUniqueNonZero(&v, hash_value);
+        }
+        for (auto & v : src.m3)
+        {
+            size_t hash_value = v.getHash(src.m3);
+            size_t buck = getBucketFromHash(hash_value);
+            impls[buck].m3.insertUniqueNonZero(&v, hash_value);
+        }
+        for (auto & v : src.ms)
+        {
+            size_t hash_value = v.getHash(src.ms);
+            size_t buck = getBucketFromHash(hash_value);
+            impls[buck].ms.insertUniqueNonZero(&v, hash_value);
+        }
+    }
+
+    // This function is mostly the same as StringHashTable::dispatch, but with
+    // added bucket computation. See the comments there.
+    template <typename Self, typename Func, typename KeyHolder>
+    static auto ALWAYS_INLINE dispatch(Self & self, KeyHolder && key_holder, Func && func)
+    {
+        const StringRef & x = keyHolderGetKey(key_holder);
+        const size_t sz = x.size;
+        if (sz == 0)
+        {
+            keyHolderDiscardKey(key_holder);
+            return func(self.impls[0].m0, VoidKey{}, 0);
+        }
+
+        const char * p = x.data;
+        // pending bits that needs to be shifted out
+        const char s = (-sz & 7) * 8;
+        union
+        {
+            StringKey8 k8;
+            StringKey16 k16;
+            StringKey24 k24;
+            UInt64 n[3];
+        };
+        StringHashTableHash hash;
+        switch ((sz - 1) >> 3)
+        {
+            case 0:
+            {
+                // first half page
+                if ((reinterpret_cast<uintptr_t>(p) & 2048) == 0)
+                {
+                    memcpy(&n[0], p, 8);
+                    n[0] &= -1ul >> s;
+                }
+                else
+                {
+                    const char * lp = x.data + x.size - 8;
+                    memcpy(&n[0], lp, 8);
+                    n[0] >>= s;
+                }
+                auto res = hash(k8);
+                auto buck = getBucketFromHash(res);
+                keyHolderDiscardKey(key_holder);
+                return func(self.impls[buck].m1, k8, res);
+            }
+            case 1:
+            {
+                memcpy(&n[0], p, 8);
+                const char * lp = x.data + x.size - 8;
+                memcpy(&n[1], lp, 8);
+                n[1] >>= s;
+                auto res = hash(k16);
+                auto buck = getBucketFromHash(res);
+                keyHolderDiscardKey(key_holder);
+                return func(self.impls[buck].m2, k16, res);
+            }
+            case 2:
+            {
+                memcpy(&n[0], p, 16);
+                const char * lp = x.data + x.size - 8;
+                memcpy(&n[2], lp, 8);
+                n[2] >>= s;
+                auto res = hash(k24);
+                auto buck = getBucketFromHash(res);
+                keyHolderDiscardKey(key_holder);
+                return func(self.impls[buck].m3, k24, res);
+            }
+            default:
+            {
+                auto res = hash(x);
+                auto buck = getBucketFromHash(res);
+                return func(self.impls[buck].ms, std::forward<KeyHolder>(key_holder), res);
+            }
+        }
+    }
+
+    template <typename KeyHolder>
+    void ALWAYS_INLINE emplace(KeyHolder && key_holder, LookupResult & it, bool & inserted)
+    {
+        dispatch(*this, key_holder, typename Impl::EmplaceCallable{it, inserted});
+    }
+
+    LookupResult ALWAYS_INLINE find(const Key x)
+    {
+        return dispatch(*this, x, typename Impl::FindCallable{});
+    }
+
+    ConstLookupResult ALWAYS_INLINE find(const Key x) const
+    {
+        return dispatch(*this, x, typename Impl::FindCallable{});
+    }
+
+    void write(DB::WriteBuffer & wb) const
+    {
+        for (size_t i = 0; i < NUM_BUCKETS; ++i)
+            impls[i].write(wb);
+    }
+
+    void writeText(DB::WriteBuffer & wb) const
+    {
+        for (size_t i = 0; i < NUM_BUCKETS; ++i)
+        {
+            if (i != 0)
+                DB::writeChar(',', wb);
+            impls[i].writeText(wb);
+        }
+    }
+
+    void read(DB::ReadBuffer & rb)
+    {
+        for (size_t i = 0; i < NUM_BUCKETS; ++i)
+            impls[i].read(rb);
+    }
+
+    void readText(DB::ReadBuffer & rb)
+    {
+        for (size_t i = 0; i < NUM_BUCKETS; ++i)
+        {
+            if (i != 0)
+                DB::assertChar(',', rb);
+            impls[i].readText(rb);
+        }
+    }
+
+    size_t size() const
+    {
+        size_t res = 0;
+        for (size_t i = 0; i < NUM_BUCKETS; ++i)
+            res += impls[i].size();
+
+        return res;
+    }
+
+    bool empty() const
+    {
+        for (size_t i = 0; i < NUM_BUCKETS; ++i)
+            if (!impls[i].empty())
+                return false;
+
+        return true;
+    }
+
+    size_t getBufferSizeInBytes() const
+    {
+        size_t res = 0;
+        for (size_t i = 0; i < NUM_BUCKETS; ++i)
+            res += impls[i].getBufferSizeInBytes();
+
+        return res;
+    }
+};
--- a/dbms/src/Common/Macros.cpp
+++ b/dbms/src/Common/Macros.cpp
@ -1,6 +1,7 @@
 #include <Poco/Util/AbstractConfiguration.h>
 #include <Common/Macros.h>
 #include <Common/Exception.h>
+#include <IO/WriteHelpers.h>


 namespace DB
@ -66,7 +67,9 @@ String Macros::expand(const String & s, size_t level, const String & database_na
        else if (macro_name == "table" && !table_name.empty())
            res += table_name;
        else
-            throw Exception("No macro " + macro_name + " in config", ErrorCodes::SYNTAX_ERROR);
+            throw Exception("No macro '" + macro_name +
+                "' in config while processing substitutions in '" + s + "' at "
+                + toString(begin), ErrorCodes::SYNTAX_ERROR);

        pos = end + 1;
    }
--- a/dbms/src/Common/RadixSort.h
+++ b/dbms/src/Common/RadixSort.h
@ -165,12 +165,10 @@ struct RadixSortIntTraits


 template <typename T>
-using RadixSortNumTraits =
-    std::conditional_t<std::is_integral_v<T>,
-        std::conditional_t<std::is_unsigned_v<T>,
-            RadixSortUIntTraits<T>,
-            RadixSortIntTraits<T>>,
-        RadixSortFloatTraits<T>>;
+using RadixSortNumTraits = std::conditional_t<
+    is_integral_v<T>,
+    std::conditional_t<is_unsigned_v<T>, RadixSortUIntTraits<T>, RadixSortIntTraits<T>>,
+    RadixSortFloatTraits<T>>;


 template <typename Traits>
--- a/dbms/src/Common/SettingsChanges.h
+++ b/dbms/src/Common/SettingsChanges.h
@ -10,6 +10,9 @@ struct SettingChange
 {
    String name;
    Field value;
+
+    friend bool operator ==(const SettingChange & lhs, const SettingChange & rhs) { return (lhs.name == rhs.name) && (lhs.value == rhs.value); }
+    friend bool operator !=(const SettingChange & lhs, const SettingChange & rhs) { return !(lhs == rhs); }
 };

 using SettingsChanges = std::vector<SettingChange>;
--- a/dbms/src/Common/SpaceSaving.h
+++ b/dbms/src/Common/SpaceSaving.h
@ -369,7 +369,7 @@ private:
        if (!it)
            return nullptr;

-        return *lookupResultGetMapped(it);
+        return it->getMapped();
    }

    void rebuildCounterMap()
--- a/dbms/src/Common/StackTrace.cpp
+++ b/dbms/src/Common/StackTrace.cpp
@ -30,7 +30,7 @@ std::string signalToErrorMessage(int sig, const siginfo_t & info, const ucontext
            else
                error << "Address: " << info.si_addr;

-#if defined(__x86_64__) && !defined(__FreeBSD__) && !defined(__APPLE__)
+#if defined(__x86_64__) && !defined(__FreeBSD__) && !defined(__APPLE__) && !defined(__arm__)
            auto err_mask = context.uc_mcontext.gregs[REG_ERR];
            if ((err_mask & 0x02))
                error << " Access: write.";
--- a/dbms/src/Common/UInt128.h
+++ b/dbms/src/Common/UInt128.h
@ -182,18 +182,8 @@ struct UInt256HashCRC32
 struct UInt256HashCRC32 : public UInt256Hash {};

 #endif
-}

-/// Overload hash for type casting
-namespace std
-{
-template <> struct hash<DB::UInt128>
-{
-    size_t operator()(const DB::UInt128 & u) const
-    {
-        return CityHash_v1_0_2::Hash128to64({u.low, u.high});
-    }
-};
+}

 template <> struct is_signed<DB::UInt128>
 {
@ -215,4 +205,16 @@ template <> struct is_arithmetic<DB::UInt128>
 {
    static constexpr bool value = false;
 };
+
+/// Overload hash for type casting
+namespace std
+{
+template <> struct hash<DB::UInt128>
+{
+    size_t operator()(const DB::UInt128 & u) const
+    {
+        return CityHash_v1_0_2::Hash128to64({u.low, u.high});
+    }
+};
+
 }
--- a/dbms/src/Common/XDBCBridgeHelper.h
+++ b/dbms/src/Common/XDBCBridgeHelper.h
@ -68,7 +68,7 @@ protected:
 public:
    using Configuration = Poco::Util::AbstractConfiguration;

-    Context & context;
+    const Context & context;
    const Configuration & config;

    static constexpr inline auto DEFAULT_HOST = "localhost";
@ -79,7 +79,7 @@ public:
    static constexpr inline auto IDENTIFIER_QUOTE_HANDLER = "/identifier_quote";
    static constexpr inline auto PING_OK_ANSWER = "Ok.";

-    XDBCBridgeHelper(Context & global_context_, const Poco::Timespan & http_timeout_, const std::string & connection_string_)
+    XDBCBridgeHelper(const Context & global_context_, const Poco::Timespan & http_timeout_, const std::string & connection_string_)
        : http_timeout(http_timeout_), connection_string(connection_string_), context(global_context_), config(context.getConfigRef())
    {
        size_t bridge_port = config.getUInt(BridgeHelperMixin::configPrefix() + ".port", DEFAULT_PORT);
--- a/dbms/src/Common/tests/auto_array.cpp
+++ b/dbms/src/Common/tests/auto_array.cpp
@ -155,10 +155,10 @@ int main(int argc, char ** argv)
            map.emplace(rand(), it, inserted);
            if (inserted)
            {
-                new(lookupResultGetMapped(it)) Arr(n);
+                new (&it->getMapped()) Arr(n);

                for (size_t j = 0; j < n; ++j)
-                    (*lookupResultGetMapped(it))[j] = field;
+                    (it->getMapped())[j] = field;
            }
        }

--- a/dbms/src/Common/tests/int_hashes_perf.cpp
+++ b/dbms/src/Common/tests/int_hashes_perf.cpp
@ -31,7 +31,7 @@ void setAffinity()

 static inline ALWAYS_INLINE UInt64 rdtsc()
 {
-#if __x86_64__
+#if defined(__x86_64__)
    UInt32 a, d;
    __asm__ volatile ("rdtsc" : "=a" (a), "=d" (d));
    return static_cast<UInt64>(a) | (static_cast<UInt64>(d) << 32);
@ -109,7 +109,7 @@ static inline size_t murmurMix(UInt64 x)
 }


-#if __x86_64__
+#if defined(__x86_64__)
 static inline size_t crc32Hash(UInt64 x)
 {
    UInt64 crc = -1ULL;
@ -309,7 +309,7 @@ int main(int argc, char ** argv)
    if (!method || method == 8) test<mulShift>  (n, data.data(), "7: mulShift");
    if (!method || method == 9) test<tabulation>(n, data.data(), "8: tabulation");

-#if __x86_64__
+#if defined(__x86_64__)
    if (!method || method == 10) test<crc32Hash> (n, data.data(), "9: crc32");
 #endif

--- a/dbms/src/Common/tests/parallel_aggregation.cpp
+++ b/dbms/src/Common/tests/parallel_aggregation.cpp
@ -82,14 +82,14 @@ void aggregate12(Map & map, Source::const_iterator begin, Source::const_iterator
    {
        if (prev_it != end && *it == *prev_it)
        {
-            ++*lookupResultGetMapped(found);
+            ++found->getMapped();
            continue;
        }
        prev_it = it;

        bool inserted;
        map.emplace(*it, found, inserted);
-        ++*lookupResultGetMapped(found);
+        ++found->getMapped();
    }
 }

@ -107,14 +107,14 @@ void aggregate22(MapTwoLevel & map, Source::const_iterator begin, Source::const_
    {
        if (*it == *prev_it)
        {
-            ++*lookupResultGetMapped(found);
+            ++found->getMapped();
            continue;
        }
        prev_it = it;

        bool inserted;
        map.emplace(*it, found, inserted);
-        ++*lookupResultGetMapped(found);
+        ++found->getMapped();
    }
 }

@ -126,7 +126,7 @@ void merge2(MapTwoLevel * maps, size_t num_threads, size_t bucket)
 {
    for (size_t i = 1; i < num_threads; ++i)
        for (auto it = maps[i].impls[bucket].begin(); it != maps[i].impls[bucket].end(); ++it)
-            maps[0].impls[bucket][it->getFirst()] += it->getSecond();
+            maps[0].impls[bucket][it->getKey()] += it->getMapped();
 }

 void aggregate3(Map & local_map, Map & global_map, Mutex & mutex, Source::const_iterator begin, Source::const_iterator end)
@ -138,7 +138,7 @@ void aggregate3(Map & local_map, Map & global_map, Mutex & mutex, Source::const_
        auto found = local_map.find(*it);

        if (found)
-            ++*lookupResultGetMapped(found);
+            ++found->getMapped();
        else if (local_map.size() < threshold)
            ++local_map[*it];    /// TODO You could do one lookup, not two.
        else
@ -163,13 +163,13 @@ void aggregate33(Map & local_map, Map & global_map, Mutex & mutex, Source::const
        Map::LookupResult found;
        bool inserted;
        local_map.emplace(*it, found, inserted);
-        ++*lookupResultGetMapped(found);
+        ++found->getMapped();

        if (inserted && local_map.size() == threshold)
        {
            std::lock_guard<Mutex> lock(mutex);
            for (auto & value_type : local_map)
-                global_map[value_type.getFirst()] += value_type.getSecond();
+                global_map[value_type.getKey()] += value_type.getMapped();

            local_map.clear();
        }
@ -198,7 +198,7 @@ void aggregate4(Map & local_map, MapTwoLevel & global_map, Mutex * mutexes, Sour
                auto found = local_map.find(*it);

                if (found)
-                    ++*lookupResultGetMapped(found);
+                    ++found->getMapped();
                else
                {
                    size_t hash_value = global_map.hash(*it);
@ -311,7 +311,7 @@ int main(int argc, char ** argv)

        for (size_t i = 1; i < num_threads; ++i)
            for (auto it = maps[i].begin(); it != maps[i].end(); ++it)
-                maps[0][it->getFirst()] += it->getSecond();
+                maps[0][it->getKey()] += it->getMapped();

        watch.stop();
        double time_merged = watch.elapsedSeconds();
@ -365,7 +365,7 @@ int main(int argc, char ** argv)

        for (size_t i = 1; i < num_threads; ++i)
            for (auto it = maps[i].begin(); it != maps[i].end(); ++it)
-                maps[0][it->getFirst()] += it->getSecond();
+                maps[0][it->getKey()] += it->getMapped();

        watch.stop();

@ -435,7 +435,7 @@ int main(int argc, char ** argv)
                    continue;

                finish = false;
-                maps[0][iterators[i]->getFirst()] += iterators[i]->getSecond();
+                maps[0][iterators[i]->getKey()] += iterators[i]->getMapped();
                ++iterators[i];
            }

@ -623,7 +623,7 @@ int main(int argc, char ** argv)

        for (size_t i = 0; i < num_threads; ++i)
            for (auto it = local_maps[i].begin(); it != local_maps[i].end(); ++it)
-                global_map[it->getFirst()] += it->getSecond();
+                global_map[it->getKey()] += it->getMapped();

        pool.wait();

@ -689,7 +689,7 @@ int main(int argc, char ** argv)

        for (size_t i = 0; i < num_threads; ++i)
            for (auto it = local_maps[i].begin(); it != local_maps[i].end(); ++it)
-                global_map[it->getFirst()] += it->getSecond();
+                global_map[it->getKey()] += it->getMapped();

        pool.wait();

@ -760,7 +760,7 @@ int main(int argc, char ** argv)

        for (size_t i = 0; i < num_threads; ++i)
            for (auto it = local_maps[i].begin(); it != local_maps[i].end(); ++it)
-                global_map[it->getFirst()] += it->getSecond();
+                global_map[it->getKey()] += it->getMapped();

        pool.wait();

--- a/dbms/src/Common/tests/parallel_aggregation2.cpp
+++ b/dbms/src/Common/tests/parallel_aggregation2.cpp
@ -51,9 +51,9 @@ struct AggregateIndependent
                    map.emplace(*it, place, inserted);

                    if (inserted)
-                        creator(*lookupResultGetMapped(place));
+                        creator(place->getMapped());
                    else
-                        updater(*lookupResultGetMapped(place));
+                        updater(place->getMapped());
                }
            });
        }
@ -93,7 +93,7 @@ struct AggregateIndependentWithSequentialKeysOptimization
                {
                    if (it != begin && *it == prev_key)
                    {
-                        updater(*lookupResultGetMapped(place));
+                        updater(place->getMapped());
                        continue;
                    }
                    prev_key = *it;
@ -102,9 +102,9 @@ struct AggregateIndependentWithSequentialKeysOptimization
                    map.emplace(*it, place, inserted);

                    if (inserted)
-                        creator(*lookupResultGetMapped(place));
+                        creator(place->getMapped());
                    else
-                        updater(*lookupResultGetMapped(place));
+                        updater(place->getMapped());
                }
            });
        }
@ -131,7 +131,7 @@ struct MergeSequential
            auto begin = source_maps[i]->begin();
            auto end = source_maps[i]->end();
            for (auto it = begin; it != end; ++it)
-                merger((*source_maps[0])[it->getFirst()], it->getSecond());
+                merger((*source_maps[0])[it->getKey()], it->getMapped());
        }

        result_map = source_maps[0];
@ -161,7 +161,7 @@ struct MergeSequentialTransposed    /// In practice not better than usual.
                    continue;

                finish = false;
-                merger((*result_map)[iterators[i]->getFirst()], iterators[i]->getSecond());
+                merger((*result_map)[iterators[i]->getKey()], iterators[i]->getMapped());
                ++iterators[i];
            }

--- a/dbms/src/Common/tests/small_table.cpp
+++ b/dbms/src/Common/tests/small_table.cpp
@ -42,7 +42,7 @@ int main(int, char **)
        cont[1] = "Goodbye.";

        for (auto x : cont)
-            std::cerr << x.getFirst() << " -> " << x.getSecond() << std::endl;
+            std::cerr << x.getKey() << " -> " << x.getMapped() << std::endl;

        DB::WriteBufferFromOwnString wb;
        cont.writeText(wb);
--- a/dbms/src/Compression/CompressionCodecDoubleDelta.cpp
+++ b/dbms/src/Compression/CompressionCodecDoubleDelta.cpp
@ -109,7 +109,7 @@ UInt32 compressDataForType(const char * source, UInt32 source_size, char * dest)
 {
    // Since only unsinged int has granted 2-compliment overflow handling, we are doing math here on unsigned types.
    // To simplify and booletproof code, we operate enforce ValueType to be unsigned too.
-    static_assert(std::is_unsigned_v<ValueType>, "ValueType must be unsigned.");
+    static_assert(is_unsigned_v<ValueType>, "ValueType must be unsigned.");
    using UnsignedDeltaType = ValueType;

    // We use signed delta type to turn huge unsigned values into smaller signed:
@ -189,7 +189,7 @@ UInt32 compressDataForType(const char * source, UInt32 source_size, char * dest)
 template <typename ValueType>
 void decompressDataForType(const char * source, UInt32 source_size, char * dest)
 {
-    static_assert(std::is_unsigned_v<ValueType>, "ValueType must be unsigned.");
+    static_assert(is_unsigned_v<ValueType>, "ValueType must be unsigned.");
    using UnsignedDeltaType = ValueType;
    using SignedDeltaType = typename std::make_signed<UnsignedDeltaType>::type;

--- a/dbms/src/Compression/CompressionCodecT64.cpp
+++ b/dbms/src/Compression/CompressionCodecT64.cpp
@ -262,10 +262,10 @@ void reverseTranspose(const char * src, T * buf, UInt32 num_bits, UInt32 tail =
        reverseTransposeBytes(matrix, col, buf[col]);
 }

-template <typename T, typename MinMaxT = std::conditional_t<std::is_signed_v<T>, Int64, UInt64>>
+template <typename T, typename MinMaxT = std::conditional_t<is_signed_v<T>, Int64, UInt64>>
 void restoreUpperBits(T * buf, T upper_min, T upper_max [[maybe_unused]], T sign_bit [[maybe_unused]], UInt32 tail = 64)
 {
-    if constexpr (std::is_signed_v<T>)
+    if constexpr (is_signed_v<T>)
    {
        /// Restore some data as negatives and others as positives
        if (sign_bit)
@ -334,7 +334,7 @@ using Variant = CompressionCodecT64::Variant;
 template <typename T, bool full>
 UInt32 compressData(const char * src, UInt32 bytes_size, char * dst)
 {
-    using MinMaxType = std::conditional_t<std::is_signed_v<T>, Int64, UInt64>;
+    using MinMaxType = std::conditional_t<is_signed_v<T>, Int64, UInt64>;

    static constexpr const UInt32 matrix_size = 64;
    static constexpr const UInt32 header_size = 2 * sizeof(UInt64);
@ -389,7 +389,7 @@ UInt32 compressData(const char * src, UInt32 bytes_size, char * dst)
 template <typename T, bool full>
 void decompressData(const char * src, UInt32 bytes_size, char * dst, UInt32 uncompressed_size)
 {
-    using MinMaxType = std::conditional_t<std::is_signed_v<T>, Int64, UInt64>;
+    using MinMaxType = std::conditional_t<is_signed_v<T>, Int64, UInt64>;

    static constexpr const UInt32 matrix_size = 64;
    static constexpr const UInt32 header_size = 2 * sizeof(UInt64);
@ -441,7 +441,7 @@ void decompressData(const char * src, UInt32 bytes_size, char * dst, UInt32 unco
    if (num_bits < 64)
        upper_min = UInt64(min) >> num_bits << num_bits;

-    if constexpr (std::is_signed_v<T>)
+    if constexpr (is_signed_v<T>)
    {
        if (min < 0 && max >= 0 && num_bits < 64)
        {
--- a/Show More
+++ b/Show More