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Co-authored-by: olgarev <56617294+olgarev@users.noreply.github.com>

docs/en/operations/settings/settings.md

@@ -1729,23 +1729,23 @@ Default value: 0.
 
 ## optimize_functions_to_subcolumns {#optimize-functions-to-subcolumns}
 
-Optimizes functions (if possible) by transforming them to read the subcolumns. This reduces the amount of read data. 
+Enables or disables optimization by transforming some functions to reading subcolumns. This reduces the amount of data to read. 
 
-These function can be tranformed:
+These functions can be transformed:
 
--   [length](../../sql-reference/functions/array-functions.md#array_functions-length) to read subcolumn [size0](../../sql-reference/data-types/array.md#array-size).
--   [empty](../../sql-reference/functions/array-functions.md#function-empty) to read subcolumn [size0](../../sql-reference/data-types/array.md#array-size).
--   [notEmpty](../../sql-reference/functions/array-functions.md#function-notempty) to read subcolumn [size0](../../sql-reference/data-types/array.md#array-size).
--   [isNull](../../sql-reference/operators/index.md#operator-is-null) to read subcolumn [null](../../sql-reference/data-types/nullable.md#finding-null).
--   [isNotNull](../../sql-reference/operators/index.md#is-not-null) to read subcolumn [null](../../sql-reference/data-types/nullable.md#finding-null).
--   [count](../../sql-reference/aggregate-functions/reference/count.md) to read subcolumn [null](../../sql-reference/data-types/nullable.md#finding-null).
--   [mapKeys](../../sql-reference/functions/tuple-map-functions.md#mapkeys) to read subcolumn [keys](../../sql-reference/data-types/map.md#subcolumn-keys).
--   [mapValues](../../sql-reference/functions/tuple-map-functions.md#mapvalues) to read subcolumn [values](../../sql-reference/data-types/map.md#subcolumn-values).
+-   [length](../../sql-reference/functions/array-functions.md#array_functions-length) to read the [size0](../../sql-reference/data-types/array.md#array-size) subcolumn.
+-   [empty](../../sql-reference/functions/array-functions.md#function-empty) to read the [size0](../../sql-reference/data-types/array.md#array-size) subcolumn.
+-   [notEmpty](../../sql-reference/functions/array-functions.md#function-notempty) to read the [size0](../../sql-reference/data-types/array.md#array-size) subcolumn.
+-   [isNull](../../sql-reference/operators/index.md#operator-is-null) to read the [null](../../sql-reference/data-types/nullable.md#finding-null) subcolumn.
+-   [isNotNull](../../sql-reference/operators/index.md#is-not-null) to read the [null](../../sql-reference/data-types/nullable.md#finding-null) subcolumn.
+-   [count](../../sql-reference/aggregate-functions/reference/count.md) to read the [null](../../sql-reference/data-types/nullable.md#finding-null) subcolumn.
+-   [mapKeys](../../sql-reference/functions/tuple-map-functions.md#mapkeys) to read the [keys](../../sql-reference/data-types/map.md#subcolumn-keys) subcolumn.
+-   [mapValues](../../sql-reference/functions/tuple-map-functions.md#mapvalues) to read the [values](../../sql-reference/data-types/map.md#subcolumn-values) subcolumn.
 
 Possible values:
 
--   0 — Disabled.
--   1 — Enabled.
+-   0 — Optimization disabled.
+-   1 — Optimization enabled.
 
 Default value: `0`.
 

docs/en/sql-reference/aggregate-functions/reference/count.md

@@ -31,7 +31,7 @@ ClickHouse supports the `COUNT(DISTINCT ...)` syntax. The behavior of this const
 
 The `SELECT count() FROM table` query is not optimized, because the number of entries in the table is not stored separately. It chooses a small column from the table and counts the number of values in it.
 
-Can be optimized by the setting [optimize_functions_to_subcolumns](../../../operations/settings/settings.md#optimize-functions-to-subcolumns). With `optimize_functions_to_subcolumns = 1` the function reads subcolumn [null](../../../sql-reference/data-types/nullable.md#finding-null).
+The `SELECT count() FROM table` query can be optimized by enabling the [optimize_functions_to_subcolumns](../../../operations/settings/settings.md#optimize-functions-to-subcolumns) setting. With `optimize_functions_to_subcolumns = 1` the function reads only [null](../../../sql-reference/data-types/nullable.md#finding-null) subcolumn instead of reading and processing the whole table data.
 
 **Examples**
 

docs/en/sql-reference/data-types/map.md

@@ -76,9 +76,9 @@ SELECT CAST(([1, 2, 3], ['Ready', 'Steady', 'Go']), 'Map(UInt8, String)') AS map
 └───────────────────────────────┘
 ```
 
-## Subcolumn Map.keys {#subcolumn-keys}
+## Map.keys and Map.values Subcolumns {#map-subcolumns}
 
-To read all keys of a `Map` you can use the subcolumn `keys`, which doesn't read the whole column.
+To optimize `Map` column processing, in some cases you can use the `keys` and 'values' subcolumns instead of reading the whole column.
 
 **Example**
 
@@ -90,6 +90,8 @@ CREATE TABLE t_map (`a` Map(String, UInt64)) ENGINE = Memory;
 INSERT INTO t_map VALUES (map('key1', 1, 'key2', 2, 'key3', 3));
 
 SELECT a.keys FROM t_map;
+
+SELECT a.values FROM t_map;
 ```
 
 Result:
@@ -98,27 +100,7 @@ Result:
 ┌─a.keys─────────────────┐
 │ ['key1','key2','key3'] │
 └────────────────────────┘
-```
 
-## Subcolumn Map.values {#subcolumn-keys}
-
-To read all values of a `Map` you can use the subcolumn `values`, which doesn't read the whole column.
-
-**Example**
-
-Query:
-
-``` sql
-CREATE TABLE t_map (`a` Map(String, UInt64)) ENGINE = Memory;
-
-INSERT INTO t_map VALUES (map('key1', 1, 'key2', 2, 'key3', 3))
-
-SELECT a.values FROM t_map;
-```
-
-Result:
-
-``` text
 ┌─a.values─┐
 │ [1,2,3]  │
 └──────────┘

docs/en/sql-reference/functions/array-functions.md

@@ -11,7 +11,7 @@ Returns 1 for an empty array, or 0 for a non-empty array.
 The result type is UInt8.
 The function also works for strings.
 
-Can be optimized by the setting [optimize_functions_to_subcolumns](../../operations/settings/settings.md#optimize-functions-to-subcolumns). With `optimize_functions_to_subcolumns = 1` the function reads subcolumn [size0](../../sql-reference/data-types/array.md#array-size).
+Can be optimized by enabling the [optimize_functions_to_subcolumns](../../operations/settings/settings.md#optimize-functions-to-subcolumns) setting. With `optimize_functions_to_subcolumns = 1` the function reads only [size0](../../sql-reference/data-types/array.md#array-size) subcolumn instead of reading and processing the whole array column.
 
 ## notEmpty {#function-notempty}
 
@@ -19,7 +19,7 @@ Returns 0 for an empty array, or 1 for a non-empty array.
 The result type is UInt8.
 The function also works for strings.
 
-Can be optimized by the setting [optimize_functions_to_subcolumns](../../operations/settings/settings.md#optimize-functions-to-subcolumns). With `optimize_functions_to_subcolumns = 1` the function reads subcolumn [size0](../../sql-reference/data-types/array.md#array-size).
+Can be optimized by enabling the [optimize_functions_to_subcolumns](../../operations/settings/settings.md#optimize-functions-to-subcolumns) setting. With `optimize_functions_to_subcolumns = 1` the function reads only [size0](../../sql-reference/data-types/array.md#array-size) subcolumn instead of reading and processing the whole array column.
 
 ## length {#array_functions-length}
 
@@ -27,7 +27,7 @@ Returns the number of items in the array.
 The result type is UInt64.
 The function also works for strings.
 
-Can be optimized by the setting [optimize_functions_to_subcolumns](../../operations/settings/settings.md#optimize-functions-to-subcolumns). With `optimize_functions_to_subcolumns = 1` the function reads subcolumn [size0](../../sql-reference/data-types/array.md#array-size).
+Can be optimized by enabling the [optimize_functions_to_subcolumns](../../operations/settings/settings.md#optimize-functions-to-subcolumns) setting. With `optimize_functions_to_subcolumns = 1` the function reads only [size0](../../sql-reference/data-types/array.md#array-size) subcolumn instead of reading and processing the whole array column.
 
 ## emptyArrayUInt8, emptyArrayUInt16, emptyArrayUInt32, emptyArrayUInt64 {#emptyarrayuint8-emptyarrayuint16-emptyarrayuint32-emptyarrayuint64}
 

docs/en/sql-reference/functions/tuple-map-functions.md

@@ -220,7 +220,7 @@ Result:
 
 Returns all keys from the `map` parameter.
 
-Can be optimized by setting the [optimize_functions_to_subcolumns](../../operations/settings/settings.md#optimize-functions-to-subcolumns). With `optimize_functions_to_subcolumns = 1` the function reads subcolumn [keys](../../sql-reference/data-types/map.md#subcolumn-keys).
+Can be optimized by enabling the [optimize_functions_to_subcolumns](../../operations/settings/settings.md#optimize-functions-to-subcolumns) setting. With `optimize_functions_to_subcolumns = 1` the function reads only [keys](../../sql-reference/data-types/map.md#map-subcolumns) subcolumn instead of reading and processing the whole column data.
 
 **Syntax**
 
@@ -263,7 +263,7 @@ Result:
 
 Returns all values from the `map` parameter.
 
-Can be optimized by the setting [optimize_functions_to_subcolumns](../../operations/settings/settings.md#optimize-functions-to-subcolumns). With `optimize_functions_to_subcolumns = 1` the function reads subcolumn [values](../../sql-reference/data-types/map.md#subcolumn-values).
+Can be optimized by enabling the [optimize_functions_to_subcolumns](../../operations/settings/settings.md#optimize-functions-to-subcolumns) setting. With `optimize_functions_to_subcolumns = 1` the function reads only [values](../../sql-reference/data-types/map.md#map-subcolumns) subcolumn instead of reading and processing the whole column data.
 
 **Syntax**
 

docs/en/sql-reference/operators/index.md

@@ -283,7 +283,7 @@ ClickHouse supports the `IS NULL` and `IS NOT NULL` operators.
     -   `0` otherwise.
 -   For other values, the `IS NULL` operator always returns `0`.
 
-Can be optimized by the setting [optimize_functions_to_subcolumns](../../operations/settings/settings.md#optimize-functions-to-subcolumns). With `optimize_functions_to_subcolumns = 1` the function reads subcolumn [null](../../sql-reference/data-types/nullable.md#finding-null).
+Can be optimized by enabling the [optimize_functions_to_subcolumns](../../operations/settings/settings.md#optimize-functions-to-subcolumns) setting. With `optimize_functions_to_subcolumns = 1` the function reads only [null](../../sql-reference/data-types/nullable.md#finding-null) subcolumn instead of reading and processing the whole column data.
 
 <!-- -->
 
@@ -316,4 +316,4 @@ SELECT * FROM t_null WHERE y IS NOT NULL
 └───┴───┘
 ```
 
-Can be optimized by the setting [optimize_functions_to_subcolumns](../../operations/settings/settings.md#optimize-functions-to-subcolumns). With `optimize_functions_to_subcolumns = 1` the function reads subcolumn [null](../../sql-reference/data-types/nullable.md#finding-null).
+Can be optimized by enabling the [optimize_functions_to_subcolumns](../../operations/settings/settings.md#optimize-functions-to-subcolumns) setting. With `optimize_functions_to_subcolumns = 1` the function reads only [null](../../sql-reference/data-types/nullable.md#finding-null) subcolumn instead of reading and processing the whole column data.