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Add changelog for 20.11
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### ClickHouse release v20.11.2.1, 2020-11-11
#### Backward Incompatible Change
* If some `profile` was specified in `distributed_ddl` config section, then this profile could overwrite settings of `default` profile on server startup. It's fixed, now settings of distributed DDL queries should not affect global server settings. [#16635](https://github.com/ClickHouse/ClickHouse/pull/16635) ([tavplubix](https://github.com/tavplubix)).
* Restrict to use of non-comparable data types (like `AggregateFunction`) in keys (Sorting key, Primary key, Partition key, and so on). [#16601](https://github.com/ClickHouse/ClickHouse/pull/16601) ([alesapin](https://github.com/alesapin)).
* Remove `ANALYZE` and `AST` queries, and make the setting `enable_debug_queries` obsolete since now it is the part of full featured `EXPLAIN` query. [#16536](https://github.com/ClickHouse/ClickHouse/pull/16536) ([Ivan](https://github.com/abyss7)).
* Aggregate functions `boundingRatio`, `rankCorr`, `retention`, `timeSeriesGroupSum`, `timeSeriesGroupRateSum`, `windowFunnel` were erroneously made case-insensitive. Now their names are made case sensitive as designed. Only functions that are specified in SQL standard or made for compatibility with other DBMS or functions similar to those should be case-insensitive. [#16407](https://github.com/ClickHouse/ClickHouse/pull/16407) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Make `rankCorr` function return nan on insufficient data https://github.com/ClickHouse/ClickHouse/issues/16124. [#16135](https://github.com/ClickHouse/ClickHouse/pull/16135) ([hexiaoting](https://github.com/hexiaoting)).
#### New Feature
* Added support of LDAP as a user directory for locally non-existent users. [#12736](https://github.com/ClickHouse/ClickHouse/pull/12736) ([Denis Glazachev](https://github.com/traceon)).
* Add `system.replicated_fetches` table which shows currently running background fetches. [#16428](https://github.com/ClickHouse/ClickHouse/pull/16428) ([alesapin](https://github.com/alesapin)).
* Added setting `date_time_output_format`. [#15845](https://github.com/ClickHouse/ClickHouse/pull/15845) ([Maksim Kita](https://github.com/kitaisreal)).
* Added minimal web UI to ClickHouse. [#16158](https://github.com/ClickHouse/ClickHouse/pull/16158) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Allows to read/write Single protobuf message at once (w/o length-delimiters). [#15199](https://github.com/ClickHouse/ClickHouse/pull/15199) ([filimonov](https://github.com/filimonov)).
* Added initial OpenTelemetry support. ClickHouse now accepts OpenTelemetry traceparent headers over Native and HTTP protocols, and passes them downstream in some cases. The trace spans for executed queries are saved into the `system.opentelemetry_span_log` table. [#14195](https://github.com/ClickHouse/ClickHouse/pull/14195) ([Alexander Kuzmenkov](https://github.com/akuzm)).
* Allow specify primary key in column list of `CREATE TABLE` query. This is needed for compatibility with other SQL dialects. [#15823](https://github.com/ClickHouse/ClickHouse/pull/15823) ([Maksim Kita](https://github.com/kitaisreal)).
* Implement `OFFSET offset_row_count {ROW | ROWS} FETCH {FIRST | NEXT} fetch_row_count {ROW | ROWS} {ONLY | WITH TIES}` in SELECT query with ORDER BY. This is the SQL-standard way to specify `LIMIT`. [#15855](https://github.com/ClickHouse/ClickHouse/pull/15855) ([hexiaoting](https://github.com/hexiaoting)).
* `errorCodeToName` function - return variable name of the error (useful for analyzing query_log and similar). `system.errors` table - shows how many times errors has been happened (respects `system_events_show_zero_values`). [#16438](https://github.com/ClickHouse/ClickHouse/pull/16438) ([Azat Khuzhin](https://github.com/azat)).
* Added function `untuple` which is a special function which can introduce new columns to the SELECT list by expanding a named tuple. [#16242](https://github.com/ClickHouse/ClickHouse/pull/16242) ([Nikolai Kochetov](https://github.com/KochetovNicolai), [Amos Bird](https://github.com/amosbird)).
* Now we can provide identifiers via query parameters. And these parameters can be used as table objects or columns. [#16594](https://github.com/ClickHouse/ClickHouse/pull/16594) ([Amos Bird](https://github.com/amosbird)).
* Added big integers (UInt256, Int128, Int256) and UUID data types support for MergeTree BloomFilter index. Big integers is an experimental feature. [#16642](https://github.com/ClickHouse/ClickHouse/pull/16642) ([Maksim Kita](https://github.com/kitaisreal)).
* Add `farmFingerprint64` function (non-cryptographic string hashing). [#16570](https://github.com/ClickHouse/ClickHouse/pull/16570) ([Jacob Hayes](https://github.com/JacobHayes)).
* Add `log_queries_min_query_duration_ms`, only queries slower then the value of this setting will go to `query_log`/`query_thread_log` (i.e. something like `slow_query_log` in mysql). [#16529](https://github.com/ClickHouse/ClickHouse/pull/16529) ([Azat Khuzhin](https://github.com/azat)).
* Ability to create a docker image on the top of `Alpine`. Uses precompiled binary and glibc components from ubuntu 20.04. [#16479](https://github.com/ClickHouse/ClickHouse/pull/16479) ([filimonov](https://github.com/filimonov)).
* Added `toUUIDOrNull`, `toUUIDOrZero` cast functions. [#16337](https://github.com/ClickHouse/ClickHouse/pull/16337) ([Maksim Kita](https://github.com/kitaisreal)).
* Add `max_concurrent_queries_for_all_users` setting, see [#6636](https://github.com/ClickHouse/ClickHouse/issues/6636) for use cases. [#16154](https://github.com/ClickHouse/ClickHouse/pull/16154) ([nvartolomei](https://github.com/nvartolomei)).
* Add a new option `print_query_id` to clickhouse-client. It helps generate arbitrary strings with the current query id generated by the client. Also print query id in clickhouse-client by default. [#15809](https://github.com/ClickHouse/ClickHouse/pull/15809) ([Amos Bird](https://github.com/amosbird)).
* Add `tid` and `logTrace` functions. This closes [#9434](https://github.com/ClickHouse/ClickHouse/issues/9434). [#15803](https://github.com/ClickHouse/ClickHouse/pull/15803) ([flynn](https://github.com/ucasFL)).
* Add function `formatReadableTimeDelta` that format time delta to human readable string ... [#15497](https://github.com/ClickHouse/ClickHouse/pull/15497) ([Filipe Caixeta](https://github.com/filipecaixeta)).
* Added `disable_merges` option for volumes in multi-disk configuration. [#13956](https://github.com/ClickHouse/ClickHouse/pull/13956) ([Vladimir Chebotarev](https://github.com/excitoon)).
#### Experimental Feature
* New functions `encrypt`, `aes_encrypt_mysql`, `decrypt`, `aes_decrypt_mysql`. These functions are working slowly, so we consider it as an experimental feature. [#11844](https://github.com/ClickHouse/ClickHouse/pull/11844) ([Vasily Nemkov](https://github.com/Enmk)).
#### Bug Fix
* Mask password in data_path in the `system.distribution_queue`. [#16727](https://github.com/ClickHouse/ClickHouse/pull/16727) ([Azat Khuzhin](https://github.com/azat)).
* Fix `IN` operator over several columns and tuples with enabled `transform_null_in` setting. Fixes [#15310](https://github.com/ClickHouse/ClickHouse/issues/15310). [#16722](https://github.com/ClickHouse/ClickHouse/pull/16722) ([Anton Popov](https://github.com/CurtizJ)).
* The setting `max_parallel_replicas` worked incorrectly if the queried table has no sampling. This fixes [#5733](https://github.com/ClickHouse/ClickHouse/issues/5733). [#16675](https://github.com/ClickHouse/ClickHouse/pull/16675) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix optimize_read_in_order/optimize_aggregation_in_order with max_threads > 0 and expression in ORDER BY. [#16637](https://github.com/ClickHouse/ClickHouse/pull/16637) ([Azat Khuzhin](https://github.com/azat)).
* Calculation of `DEFAULT` expressions was involving possible name collisions (that was very unlikely to encounter). This fixes [#9359](https://github.com/ClickHouse/ClickHouse/issues/9359). [#16612](https://github.com/ClickHouse/ClickHouse/pull/16612) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix `query_thread_log.query_duration_ms` unit. [#16563](https://github.com/ClickHouse/ClickHouse/pull/16563) ([Azat Khuzhin](https://github.com/azat)).
* Fix a bug when using MySQL Master -> MySQL Slave -> ClickHouse MaterializeMySQL Engine. `MaterializeMySQL` is an experimental feature. [#16504](https://github.com/ClickHouse/ClickHouse/pull/16504) ([TCeason](https://github.com/TCeason)).
* Specifically crafted argument of `round` function with `Decimal` was leading to integer division by zero. This fixes [#13338](https://github.com/ClickHouse/ClickHouse/issues/13338). [#16451](https://github.com/ClickHouse/ClickHouse/pull/16451) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix DROP TABLE for Distributed (racy with INSERT). [#16409](https://github.com/ClickHouse/ClickHouse/pull/16409) ([Azat Khuzhin](https://github.com/azat)).
* Fix processing of very large entries in replication queue. Very large entries may appear in ALTER queries if table structure is extremely large (near 1 MB). This fixes [#16307](https://github.com/ClickHouse/ClickHouse/issues/16307). [#16332](https://github.com/ClickHouse/ClickHouse/pull/16332) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fixed the inconsistent behaviour when a part of return data could be dropped because the set for its filtration wasn't created. [#16308](https://github.com/ClickHouse/ClickHouse/pull/16308) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Fix dictGet in sharding_key (and similar places, i.e. when the function context is stored permanently). [#16205](https://github.com/ClickHouse/ClickHouse/pull/16205) ([Azat Khuzhin](https://github.com/azat)).
* Fix the exception thrown in `clickhouse-local` when trying to execute `OPTIMIZE` command. Fixes [#16076](https://github.com/ClickHouse/ClickHouse/issues/16076). [#16192](https://github.com/ClickHouse/ClickHouse/pull/16192) ([filimonov](https://github.com/filimonov)).
* Fixes [#15780](https://github.com/ClickHouse/ClickHouse/issues/15780) regression, e.g. `indexOf([1, 2, 3], toLowCardinality(1))` now is prohibited but it should not be. [#16038](https://github.com/ClickHouse/ClickHouse/pull/16038) ([Mike](https://github.com/myrrc)).
* Fix bug with MySQL database. When MySQL server used as database engine is down some queries raise Exception, because they try to get tables from disabled server, while it's unnecessary. For example, query `SELECT ... FROM system.parts` should work only with MergeTree tables and don't touch MySQL database at all. [#16032](https://github.com/ClickHouse/ClickHouse/pull/16032) ([Kruglov Pavel](https://github.com/Avogar)).
* Now exception will be thrown when `ALTER MODIFY COLUMN ... DEFAULT ...` has incompatible default with column type. Fixes [#15854](https://github.com/ClickHouse/ClickHouse/issues/15854). [#15858](https://github.com/ClickHouse/ClickHouse/pull/15858) ([alesapin](https://github.com/alesapin)).
* Fixed IPv4CIDRToRange/IPv6CIDRToRange functions to accept const IP-column values. [#15856](https://github.com/ClickHouse/ClickHouse/pull/15856) ([vladimir-golovchenko](https://github.com/vladimir-golovchenko)).
#### Improvement
* Treat `INTERVAL '1 hour'` as equivalent to `INTERVAL 1 HOUR`, to be compatible with Postgres and similar. This fixes [#15637](https://github.com/ClickHouse/ClickHouse/issues/15637). [#15978](https://github.com/ClickHouse/ClickHouse/pull/15978) ([flynn](https://github.com/ucasFL)).
* Enable parsing enum values by their numeric ids for CSV, TSV and JSON input formats. [#15685](https://github.com/ClickHouse/ClickHouse/pull/15685) ([vivarum](https://github.com/vivarum)).
* Better read task scheduling for JBOD architecture and `MergeTree` storage. New setting `read_backoff_min_concurrency` which serves as the lower limit to the number of reading threads. [#16423](https://github.com/ClickHouse/ClickHouse/pull/16423) ([Amos Bird](https://github.com/amosbird)).
* Add missing support for `LowCardinality` in `Avro` format. [#16521](https://github.com/ClickHouse/ClickHouse/pull/16521) ([Mike](https://github.com/myrrc)).
* Workaround for use `S3` with nginx server as proxy. Nginx currenty does not accept urls with empty path like `http://domain.com?delete`, but vanilla aws-sdk-cpp produces this kind of urls. This commit uses patched aws-sdk-cpp version, which makes urls with "/" as path in this cases, like http://domain.com/?delete. [#16814](https://github.com/ClickHouse/ClickHouse/pull/16814) ([ianton-ru](https://github.com/ianton-ru)).
* Better diagnostics on parse errors in input data. Provide row number on `Cannot read all data` errors. [#16644](https://github.com/ClickHouse/ClickHouse/pull/16644) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Make the behaviour of `minMap` and `maxMap` more desireable. It will not skip zero values in the result. Fixes [#16087](https://github.com/ClickHouse/ClickHouse/issues/16087). [#16631](https://github.com/ClickHouse/ClickHouse/pull/16631) ([Ildus Kurbangaliev](https://github.com/ildus)).
* Better update of ZooKeeper configuration in runtime. [#16630](https://github.com/ClickHouse/ClickHouse/pull/16630) ([sundyli](https://github.com/sundy-li)).
* Apply SETTINGS clause as early as possible. It allows to modify more settings in the query. This closes [#3178](https://github.com/ClickHouse/ClickHouse/issues/3178). [#16619](https://github.com/ClickHouse/ClickHouse/pull/16619) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Now `event_time_microseconds` field stores in Decimal64, not UInt64. [#16617](https://github.com/ClickHouse/ClickHouse/pull/16617) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
* Now paratmeterized functions can be used in `APPLY` column transformer. [#16589](https://github.com/ClickHouse/ClickHouse/pull/16589) ([Amos Bird](https://github.com/amosbird)).
* Improve scheduling of background task which removes data of dropped tables in `Atomic` databases. `Atomic` databases do not create broken symlink to table data directory if table actually has no data directory. [#16584](https://github.com/ClickHouse/ClickHouse/pull/16584) ([tavplubix](https://github.com/tavplubix)).
* Subqueries in `WITH` section (CTE) can reference previous subqueries in `WITH` section by their name. [#16575](https://github.com/ClickHouse/ClickHouse/pull/16575) ([Amos Bird](https://github.com/amosbird)).
* Add current_database into `system.query_thread_log`. [#16558](https://github.com/ClickHouse/ClickHouse/pull/16558) ([Azat Khuzhin](https://github.com/azat)).
* Allow to fetch parts that are already committed or outdated in the current instance into the detached directory. It's useful when migrating tables from another cluster and having N to 1 shards mapping. It's also consistent with the current fetchPartition implementation. [#16538](https://github.com/ClickHouse/ClickHouse/pull/16538) ([Amos Bird](https://github.com/amosbird)).
* Multiple improvements for `RabbitMQ`: Fixed bug for [#16263](https://github.com/ClickHouse/ClickHouse/issues/16263). Also minimized event loop lifetime. Added more efficient queues setup. [#16426](https://github.com/ClickHouse/ClickHouse/pull/16426) ([Kseniia Sumarokova](https://github.com/kssenii)).
* Fix debug assertion in `quantileDeterministic` function. In previous version it may also transfer up to two times more data over the network. Although no bug existed. This fixes [#15683](https://github.com/ClickHouse/ClickHouse/issues/15683). [#16410](https://github.com/ClickHouse/ClickHouse/pull/16410) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add `TablesToDropQueueSize` metric. It's equal to number of dropped tables, that are waiting for background data removal. [#16364](https://github.com/ClickHouse/ClickHouse/pull/16364) ([tavplubix](https://github.com/tavplubix)).
* Better diagnostics when client has dropped connection. In previous versions, `Attempt to read after EOF` and `Broken pipe` exceptions were logged in server. In new version, it's information message `Client has dropped the connection, cancel the query.`. [#16329](https://github.com/ClickHouse/ClickHouse/pull/16329) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add total_rows/total_bytes (from system.tables) support for Set/Join table engines. [#16306](https://github.com/ClickHouse/ClickHouse/pull/16306) ([Azat Khuzhin](https://github.com/azat)).
* Now it's possible to specify `PRIMARY KEY` without `ORDER BY` for MergeTree table engines family. Closes [#15591](https://github.com/ClickHouse/ClickHouse/issues/15591). [#16284](https://github.com/ClickHouse/ClickHouse/pull/16284) ([alesapin](https://github.com/alesapin)).
* If there is no tmp folder in the system (chroot, misconfigutation etc) `clickhouse-local` will create temporary subfolder in the current directory. [#16280](https://github.com/ClickHouse/ClickHouse/pull/16280) ([filimonov](https://github.com/filimonov)).
* Add support for nested data types (like named tuple) as sub-types. Fixes [#15587](https://github.com/ClickHouse/ClickHouse/issues/15587). [#16262](https://github.com/ClickHouse/ClickHouse/pull/16262) ([Ivan](https://github.com/abyss7)).
* Support for `database_atomic_wait_for_drop_and_detach_synchronously`/`NO DELAY`/`SYNC` for `DROP DATABASE`. [#16127](https://github.com/ClickHouse/ClickHouse/pull/16127) ([Azat Khuzhin](https://github.com/azat)).
* Add `allow_nondeterministic_optimize_skip_unused_shards` (to allow non deterministic like `rand()` or `dictGet()` in sharding key). [#16105](https://github.com/ClickHouse/ClickHouse/pull/16105) ([Azat Khuzhin](https://github.com/azat)).
* Fix `memory_profiler_step`/`max_untracked_memory` for queries via HTTP (test included). Fix the issue that adjusting this value globally in xml config does not help either, since those settings are not applied anyway, only default (4MB) value is [used](https://github.com/ClickHouse/ClickHouse/blob/17731245336d8c84f75e4c0894c5797ed7732190/src/Common/ThreadStatus.h#L104). Fix `query_id` for the most root ThreadStatus of the http query (by initializing QueryScope after reading query_id). [#16101](https://github.com/ClickHouse/ClickHouse/pull/16101) ([Azat Khuzhin](https://github.com/azat)).
* Now it's allowed to execute `ALTER ... ON CLUSTER` queries regardless of the `<internal_replication>` setting in cluster config. [#16075](https://github.com/ClickHouse/ClickHouse/pull/16075) ([alesapin](https://github.com/alesapin)).
* Fix rare issue when `clickhouse-client` may abort on exit due to loading of suggestions. This fixes [#16035](https://github.com/ClickHouse/ClickHouse/issues/16035). [#16047](https://github.com/ClickHouse/ClickHouse/pull/16047) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add support of `cache` layout for `Redis` dictionaries with complex key. [#15985](https://github.com/ClickHouse/ClickHouse/pull/15985) ([Anton Popov](https://github.com/CurtizJ)).
* Fix query hang (endless loop) in case of misconfiguration (`connections_with_failover_max_tries` set to 0). [#15876](https://github.com/ClickHouse/ClickHouse/pull/15876) ([Azat Khuzhin](https://github.com/azat)).
* Change level of some log messages from information to debug, so information messages will not appear for every query. This closes [#5293](https://github.com/ClickHouse/ClickHouse/issues/5293). [#15816](https://github.com/ClickHouse/ClickHouse/pull/15816) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Remove `MemoryTrackingInBackground*` metrics to avoid potentially misleading results. This fixes [#15684](https://github.com/ClickHouse/ClickHouse/issues/15684). [#15813](https://github.com/ClickHouse/ClickHouse/pull/15813) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add reconnects to `zookeeper-dump-tree` tool. [#15711](https://github.com/ClickHouse/ClickHouse/pull/15711) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Allow explicitly specify columns list in `CREATE TABLE table AS table_function(...)` query. Fixes [#9249](https://github.com/ClickHouse/ClickHouse/issues/9249) Fixes [#14214](https://github.com/ClickHouse/ClickHouse/issues/14214). [#14295](https://github.com/ClickHouse/ClickHouse/pull/14295) ([tavplubix](https://github.com/tavplubix)).
#### Performance Improvement
* Do not merge parts across partitions in SELECT FINAL. [#15938](https://github.com/ClickHouse/ClickHouse/pull/15938) ([Kruglov Pavel](https://github.com/Avogar)).
* Improve performance of `-OrNull` and `-OrDefault` aggregate functions. [#16661](https://github.com/ClickHouse/ClickHouse/pull/16661) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Improve performance of `quantileMerge`. In previous versions it was obnoxiously slow. This closes [#1463](https://github.com/ClickHouse/ClickHouse/issues/1463). [#16643](https://github.com/ClickHouse/ClickHouse/pull/16643) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Improve performance of logical functions a little. [#16347](https://github.com/ClickHouse/ClickHouse/pull/16347) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Improved performance of merges assignment in MergeTree table engines. Shouldn't be visible for the user. [#16191](https://github.com/ClickHouse/ClickHouse/pull/16191) ([alesapin](https://github.com/alesapin)).
* Speedup hashed/sparse_hashed dictionary loading by preallocating the hash table. [#15454](https://github.com/ClickHouse/ClickHouse/pull/15454) ([Azat Khuzhin](https://github.com/azat)).
* Now trivial count optimization becomes slightly non-trivial. Predicates that contain exact partition expr can be optimized too. This also fixes [#11092](https://github.com/ClickHouse/ClickHouse/issues/11092) which returns wrong count when `max_parallel_replicas > 1`. [#15074](https://github.com/ClickHouse/ClickHouse/pull/15074) ([Amos Bird](https://github.com/amosbird)).
#### Build/Testing/Packaging Improvement
* Add flaky check for stateless tests. It will detect potentially flaky functional tests in advance, before they are merged. [#16238](https://github.com/ClickHouse/ClickHouse/pull/16238) ([alesapin](https://github.com/alesapin)).
* Use proper version for `croaring` instead of amalgamation. [#16285](https://github.com/ClickHouse/ClickHouse/pull/16285) ([sundyli](https://github.com/sundy-li)).
* Improve generation of build files for `ya.make` build system (Arcadia). [#16700](https://github.com/ClickHouse/ClickHouse/pull/16700) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Add MySQL BinLog file check tool for `MaterializeMySQL` database engine. `MaterializeMySQL` is an experimental feature. [#16223](https://github.com/ClickHouse/ClickHouse/pull/16223) ([Winter Zhang](https://github.com/zhang2014)).
* Check for executable bit on non-executable files. People often accidentially commit executable files from Windows. [#15843](https://github.com/ClickHouse/ClickHouse/pull/15843) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Check for `#pragma once` in headers. [#15818](https://github.com/ClickHouse/ClickHouse/pull/15818) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Fix illegal code style `&vector[idx]` in libhdfs3. This fixes libcxx debug build. See also https://github.com/ClickHouse-Extras/libhdfs3/pull/8 . [#15815](https://github.com/ClickHouse/ClickHouse/pull/15815) ([Amos Bird](https://github.com/amosbird)).
* Fix build of one miscellaneous example tool on Mac OS. Note that we don't build examples on Mac OS in our CI (we build only ClickHouse binary), so there is zero chance it will not break again. This fixes [#15804](https://github.com/ClickHouse/ClickHouse/issues/15804). [#15808](https://github.com/ClickHouse/ClickHouse/pull/15808) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Simplify Sys/V init script. [#14135](https://github.com/ClickHouse/ClickHouse/pull/14135) ([alexey-milovidov](https://github.com/alexey-milovidov)).
* Added `boost::program_options` to `db_generator` in order to increase its usability. This closes [#15940](https://github.com/ClickHouse/ClickHouse/issues/15940). [#15973](https://github.com/ClickHouse/ClickHouse/pull/15973) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
## ClickHouse release 20.10
### ClickHouse release v20.10.3.30, 2020-10-28