DOCAPI-4821. Sync between ru and en versions of docs.

docs/en/operations/configuration_files.md

@@ -14,7 +14,7 @@ If `replace` is specified, it replaces the entire element with the specified one
 
 If `remove` is specified, it deletes the element.
 
-The config can also define "substitutions". If an element has the `incl` attribute, the corresponding substitution from the file will be used as the value. By default, the path to the file with substitutions is `/etc/metrika.xml`. This can be changed in the [include_from](server_settings/settings.md#server_settings-include_from) element in the server config. The substitution values are specified in  `/yandex/substitution_name` elements in this file. If a substitution specified in `incl`  does not exist, it is recorded in the log. To prevent ClickHouse from logging missing substitutions, specify the  `optional="true"` attribute (for example, settings for [macros]() server_settings/settings.md#server_settings-macros)).
+The config can also define "substitutions". If an element has the `incl` attribute, the corresponding substitution from the file will be used as the value. By default, the path to the file with substitutions is `/etc/metrika.xml`. This can be changed in the [include_from](server_settings/settings.md#server_settings-include_from) element in the server config. The substitution values are specified in `/yandex/substitution_name` elements in this file. If a substitution specified in `incl`  does not exist, it is recorded in the log. To prevent ClickHouse from logging missing substitutions, specify the  `optional="true"` attribute (for example, settings for [macros](server_settings/settings.md#server_settings-macros)).
 
 Substitutions can also be performed from ZooKeeper. To do this, specify the attribute `from_zk = "/path/to/node"`. The element value is replaced with the contents of the node at `/path/to/node` in ZooKeeper. You can also put an entire XML subtree on the ZooKeeper node and it will be fully inserted into the source element.
 

docs/en/operations/server_settings/settings.md

@@ -532,6 +532,7 @@ Columns in the log:
 - database_name – The name of the database.
 - table_name – Name of the table.
 - part_name – Name of the data part.
+- partition_id – The identifier of the partition.
 - size_in_bytes – Size of the data part in bytes.
 - merged_from – An array of names of data parts that make up the merge (also used when downloading a merged part).
 - merge_time_ms – Time spent on the merge.

docs/en/operations/settings/query_complexity.md

@@ -2,7 +2,9 @@
 
 Restrictions on query complexity are part of the settings.
 They are used in order to provide safer execution from the user interface.
-Almost all the restrictions only apply to SELECTs.For distributed query processing, restrictions are applied on each server separately.
+Almost all the restrictions only apply to `SELECT`. For distributed query processing, restrictions are applied on each server separately.
+
+ClickHouse checks the restrictions for data parts, not for each row. It means that you can exceed the value of restriction with a size of the data part.
 
 Restrictions on the "maximum amount of something" can take the value 0, which means "unrestricted".
 Most restrictions also have an 'overflow_mode' setting, meaning what to do when the limit is exceeded.

docs/en/operations/table_engines/dictionary.md

@@ -2,7 +2,7 @@
 
 # Dictionary
 
-The `Dictionary` engine displays the dictionary data as a ClickHouse table.
+The `Dictionary` engine displays the [dictionary](../../query_language/dicts/external_dicts.md#dicts-external_dicts) data as a ClickHouse table.
 
 As an example, consider a dictionary of `products` with the following configuration:
 

docs/en/operations/table_engines/mergetree.md

@@ -135,7 +135,7 @@ If the data query specifies:
 
 - `CounterID in ('a', 'h')`, the server reads the data in the ranges of marks `[0, 3)` and `[6, 8)`.
 - `CounterID IN ('a', 'h') AND Date = 3`, the server reads the data in the ranges of marks `[1, 3)` and `[7, 8)`.
-- `Date = 3`, the server reads the data in the range of marks `[1, 10)`.
+- `Date = 3`, the server reads the data in the range of marks `[1, 10]`.
 
 The examples above show that it is always more effective to use an index than a full scan.
 

docs/en/query_language/dicts/external_dicts_dict_lifetime.md

@@ -35,13 +35,13 @@ Example of settings:
 
 When upgrading the dictionaries, the ClickHouse server applies different logic depending on the type of [ source](external_dicts_dict_sources.md#dicts-external_dicts_dict_sources):
 
-> - For a text file, it checks the time of modification. If the time differs from the previously recorded time, the dictionary is updated.
+- For a text file, it checks the time of modification. If the time differs from the previously recorded time, the dictionary is updated.
 - For MyISAM tables, the time of modification is checked using a `SHOW TABLE STATUS` query.
 - Dictionaries from other sources are updated every time by default.
 
-For MySQL (InnoDB) and ODBC sources, you can set up a query that will update the dictionaries only if they really changed, rather than each time. To do this, follow these steps:
+For MySQL (InnoDB), ODBC and ClickHouse sources, you can set up a query that will update the dictionaries only if they really changed, rather than each time. To do this, follow these steps:
 
-> - The dictionary table must have a field that always changes when the source data is updated.
+- The dictionary table must have a field that always changes when the source data is updated.
 - The settings of the source must specify a query that retrieves the changing field. The ClickHouse server interprets the query result as a row, and if this row has changed relative to its previous state, the dictionary is updated. Specify the query in the `<invalidate_query>` field in the settings for the [source](external_dicts_dict_sources.md#dicts-external_dicts_dict_sources).
 
 Example of settings:

docs/en/query_language/functions/string_search_functions.md

@@ -18,7 +18,8 @@ For a case-insensitive search, use the function `positionCaseInsensitiveUTF8`.
 
 ## match(haystack, pattern)
 
-Checks whether the string matches the 'pattern' regular expression. A re2 regular expression.
+Checks whether the string matches the `pattern` regular expression. A `re2` regular expression. The [syntax](https://github.com/google/re2/wiki/Syntax)  of the `re2` regular expressions is more limited than the syntax of the Perl regular expressions.
+
 Returns 0 if it doesn't match, or 1 if it matches.
 
 Note that the backslash symbol (`\`) is used for escaping in the regular expression. The same symbol is used for escaping in string literals. So in order to escape the symbol in a regular expression, you must write two backslashes (\\) in a string literal.

docs/en/query_language/functions/type_conversion_functions.md

@@ -12,6 +12,10 @@
 
 ## toDate, toDateTime
 
+## toDecimal32(value, S), toDecimal64(value, S), toDecimal128(value, S)
+
+Converts `value` to [Decimal](../../data_types/decimal.md#data_type-decimal) of precision `S`. The `value` can be a number or a string. The `S` (scale) parameter specifies the number of decimal places.
+
 ## toString
 
 Functions for converting between numbers, strings (but not fixed strings), dates, and dates with times.

docs/en/query_language/operators.md

@@ -91,11 +91,15 @@ The conditional operator calculates the values of b and c, then checks whether c
 CASE [x]
     WHEN a THEN b
     [WHEN ... THEN ...]
-    ELSE c
+    [ELSE c]
 END
 ```
 
-If "x" is specified, then transform(x, \[a, ...\], \[b, ...\], c). Otherwise – multiIf(a, b, ..., c).
+If `x` is specified, then `transform(x, [a, ...], [b, ...], c)` function is used. Otherwise – `multiIf(a, b, ..., c)`.
+
+If there is no `ELSE c` clause in the expression, the default value is `NULL`.
+
+The `transform` function does not work with `NULL`.
 
 ## Concatenation Operator
 

docs/ru/operations/table_engines/merge.md

@@ -24,6 +24,33 @@ Merge(hits, '^WatchLog')
 
 Типичный способ использования движка `Merge` — работа с большим количеством таблиц типа `TinyLog`, как с одной.
 
+Пример 2:
+
+Пусть есть старая таблица `WatchLog_old`. Необходимо изменить партиционирование без перемещения данных в новую таблицу `WatchLog_new`. При этом в выборке должны участвовать данные обеих таблиц.
+
+```
+CREATE TABLE WatchLog_old(date Date, UserId Int64, EventType String, Cnt UInt64) 
+ENGINE=MergeTree(date, (UserId, EventType), 8192);
+INSERT INTO WatchLog_old VALUES ('2018-01-01', 1, 'hit', 3);
+
+CREATE TABLE WatchLog_new(date Date, UserId Int64, EventType String, Cnt UInt64)
+ENGINE=MergeTree PARTITION BY date ORDER BY (UserId, EventType) SETTINGS index_granularity=8192;
+INSERT INTO WatchLog_new VALUES ('2018-01-02', 2, 'hit', 3);
+
+CREATE TABLE WatchLog as WatchLog_old ENGINE=Merge(currentDatabase(), '^WatchLog');
+
+SELECT *
+FROM WatchLog
+
+┌───────date─┬─UserId─┬─EventType─┬─Cnt─┐
+│ 2018-01-01 │      1 │ hit       │   3 │
+└────────────┴────────┴───────────┴─────┘
+┌───────date─┬─UserId─┬─EventType─┬─Cnt─┐
+│ 2018-01-02 │      2 │ hit       │   3 │
+└────────────┴────────┴───────────┴─────┘
+
+```
+
 ## Виртуальные столбцы
 
 Виртуальные столбцы — столбцы, предоставляемые движком таблиц независимо от определения таблицы. То есть, такие столбцы не указываются в `CREATE TABLE`, но доступны для `SELECT`.

docs/ru/operations/tips.md

@@ -21,7 +21,7 @@ Turbo-Boost крайне не рекомендуется отключать. П
 Нужно всегда использовать `performance` scaling governor. `ondemand` scaling governor работает намного хуже при постоянно высоком спросе.
 
 ```bash
-sudo echo 'performance' | tee /sys/devices/system/cpu/cpu\*/cpufreq/scaling_governor
+sudo echo 'performance' | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
 ```
 
 ## Ограничение CPU

docs/ru/query_language/operators.md

@@ -95,9 +95,9 @@ CASE [x]
 END
 ```
 
-В случае указания x - функция transform(x, \[a, ...\], \[b, ...\], c). Иначе - multiIf(a, b, ..., c).
-При отсутствии секции `ELSE c`, значением по умолчанию будет NULL.
-P.S. Функция transform не умеет работать с NULL.
+В случае указания `x` - функция `transform(x, [a, ...], [b, ...], c)`. Иначе — `multiIf(a, b, ..., c)`.
+При отсутствии секции `ELSE c`, значением по умолчанию будет `NULL`.
+P.S. Функция `transform` не умеет работать с `NULL`.
 
 ## Оператор склеивания строк