add document

Signed-off-by: Duc Canh Le <duccanh.le@ahrefs.com>

docs/en/engines/table-engines/mergetree-family/mergetree.md

@@ -39,8 +39,8 @@ If you need to update rows frequently, we recommend using the [`ReplacingMergeTr
 ``` sql
 CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
 (
-    name1 [type1] [[NOT] NULL] [DEFAULT|MATERIALIZED|ALIAS|EPHEMERAL expr1] [COMMENT ...] [CODEC(codec1)] [STATISTIC(stat1)] [TTL expr1] [PRIMARY KEY],
-    name2 [type2] [[NOT] NULL] [DEFAULT|MATERIALIZED|ALIAS|EPHEMERAL expr2] [COMMENT ...] [CODEC(codec2)] [STATISTIC(stat2)] [TTL expr2] [PRIMARY KEY],
+    name1 [type1] [[NOT] NULL] [DEFAULT|MATERIALIZED|ALIAS|EPHEMERAL expr1] [COMMENT ...] [CODEC(codec1)] [STATISTIC(stat1)] [TTL expr1] [PRIMARY KEY] [SETTINGS (name = value, ...)],
+    name2 [type2] [[NOT] NULL] [DEFAULT|MATERIALIZED|ALIAS|EPHEMERAL expr2] [COMMENT ...] [CODEC(codec2)] [STATISTIC(stat2)] [TTL expr2] [PRIMARY KEY] [SETTINGS (name = value, ...)],
     ...
     INDEX index_name1 expr1 TYPE type1(...) [GRANULARITY value1],
     INDEX index_name2 expr2 TYPE type2(...) [GRANULARITY value2],
@@ -1390,3 +1390,42 @@ They can be used for query optimization when we enable `set allow_statistic_opti
 -   `tdigest`
 
     Stores distribution of values from numeric columns in [TDigest](https://github.com/tdunning/t-digest) sketch.
+
+## Column Settings {#column-settings}
+
+Some table parameters can be override at column level by column settings.
+
+- `max_compress_block_size` — Maximum size of blocks of uncompressed data before compressing for writing to a table.
+- `min_compress_block_size` — Minimum size of blocks of uncompressed data required for compression when writing the next mark.
+
+Example of creating table with column settings:
+
+```sql
+CREATE TABLE example_table
+(
+    id Int64,
+    document String CODEC(ZSTD(9,24)) SETTINGS (min_compress_block_size = 16777216, max_compress_block_size = 16777216)
+)
+ENGINE = MergeTree
+ORDER BY id
+```
+
+Column settings can be modified or removed via [ALTER MODIFY COLUMN](/docs/en/sql-reference/statements/alter/column.md) query, for example:
+
+Remove `SETTINGS` from column declaration:
+
+```sql
+ALTER TABLE example_table MODIFY COLUMN document REMOVE SETTINGS;
+```
+
+Modify a setting:
+
+```sql
+ALTER TABLE example_table MODIFY COLUMN document MODIFY SETTING min_compress_block_size = 8192;
+```
+
+Reset one or more settings, after reset the setting expression is also removed from column declaration:
+
+```sql
+ALTER TABLE example_table MODIFY COLUMN document RESET SETTING min_compress_block_size;
+```

docs/en/sql-reference/statements/alter/column.md

@@ -23,10 +23,11 @@ The following actions are supported:
 - [RENAME COLUMN](#rename-column) — Renames an existing column.
 - [CLEAR COLUMN](#clear-column) — Resets column values.
 - [COMMENT COLUMN](#comment-column) — Adds a text comment to the column.
-- [MODIFY COLUMN](#modify-column) — Changes column’s type, default expression and TTL.
+- [MODIFY COLUMN](#modify-column) — Changes column’s type, default expression, TTL, and settings.
 - [MODIFY COLUMN REMOVE](#modify-column-remove) — Removes one of the column properties.
+- [MODIFY COLUMN MODIFY SETTING](#modify-column-modify-setting) - Changes column settings.
+- [MODIFY COLUMN RESET SETTING](#modify-column-reset-setting) - Reset column settings.
 - [MATERIALIZE COLUMN](#materialize-column) — Materializes the column in the parts where the column is missing.
-
 These actions are described in detail below.
 
 ## ADD COLUMN
@@ -75,7 +76,7 @@ Deletes the column with the name `name`. If the `IF EXISTS` clause is specified,
 
 Deletes data from the file system. Since this deletes entire files, the query is completed almost instantly.
 
-:::tip    
+:::tip
 You can’t delete a column if it is referenced by [materialized view](/docs/en/sql-reference/statements/create/view.md/#materialized). Otherwise, it returns an error.
 :::
 
@@ -208,7 +209,7 @@ The `ALTER` query for changing columns is replicated. The instructions are saved
 
 ## MODIFY COLUMN REMOVE
 
-Removes one of the column properties: `DEFAULT`, `ALIAS`, `MATERIALIZED`, `CODEC`, `COMMENT`, `TTL`.
+Removes one of the column properties: `DEFAULT`, `ALIAS`, `MATERIALIZED`, `CODEC`, `COMMENT`, `TTL`, `SETTING`.
 
 Syntax:
 
@@ -228,6 +229,43 @@ ALTER TABLE table_with_ttl MODIFY COLUMN column_ttl REMOVE TTL;
 
 - [REMOVE TTL](ttl.md).
 
+
+## MODIFY COLUMN MODIFY SETTING
+
+Modify a column level setting.
+
+Syntax:
+
+```sql
+ALTER TABLE table_name MODIFY COLUMN MODIFY SETTING name=value,...;
+```
+
+**Example**
+
+Modify column's `max_compress_block_size` to `1MB`:
+
+```sql
+ALTER TABLE table_name MODIFY COLUMN MODIFY SETTING max_compress_block_size = 1048576;
+```
+
+## MODIFY COLUMN RESET SETTING
+
+Reset a column setting, also remove the setting declaration in column expression in table create query.
+
+Syntax:
+
+```sql
+ALTER TABLE table_name MODIFY COLUMN RESET SETTING name,...;
+```
+
+**Example**
+
+Remove column setting `max_compress_block_size` to `1MB`:
+
+```sql
+ALTER TABLE table_name MODIFY COLUMN REMOVE SETTING max_compress_block_size;
+```
+
 ## MATERIALIZE COLUMN
 
 Materializes or updates a column with an expression for a default value (`DEFAULT` or `MATERIALIZED`).

src/Parsers/ASTColumnDeclaration.cpp

@@ -132,7 +132,7 @@ void ASTColumnDeclaration::formatImpl(const FormatSettings & format_settings, Fo
     if (settings)
     {
         format_settings.ostr << ' ' << (format_settings.hilite ? hilite_keyword : "") << "SETTINGS" << (format_settings.hilite ? hilite_none : "") << ' ' << '(';
-        settings->formatImpl(format_settings,  state, frame);
+        settings->formatImpl(format_settings, state, frame);
         format_settings.ostr << ')';
     }
 }