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sql-stmt: update synopsis to ebnf diagrams for 6 statements #17211

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sql-stmt: update synopsis to ebnf diagrams for 6 statements #17211

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84ea38e
sql-stmt: update synopsis to ebnf diagrams
lilin90 Apr 25, 2024
eac2cc0
Apply suggestions from code review
lilin90 Apr 26, 2024
6088790
Remove copyable code snippets
lilin90 May 8, 2024
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23 changes: 9 additions & 14 deletions sql-statements/sql-statement-show-create-table.md
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Expand Up @@ -10,13 +10,10 @@ aliases: ['/docs-cn/dev/sql-statements/sql-statement-show-create-table/','/docs-

## 语法图

**ShowCreateTableStmt:**

![ShowCreateTableStmt](/media/sqlgram/ShowCreateTableStmt.png)

**TableName:**

![TableName](/media/sqlgram/TableName.png)
```ebnf+diagram
ShowCreateTableStmt ::=
"SHOW" "CREATE" "TABLE" (SchemaName ".")? TableName
```

## 示例

Expand All @@ -33,17 +30,15 @@ Query OK, 0 rows affected (0.12 sec)
{{< copyable "sql" >}}

```sql
SHOW CREATE TABLE t1;
SHOW CREATE TABLE t1\G
```

```
+-------+------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+-------+------------------------------------------------------------------------------------------------------------+
| t1 | CREATE TABLE `t1` (
*************************** 1. row ***************************
Table: t1
Create Table: CREATE TABLE `t1` (
`a` int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin |
+-------+------------------------------------------------------------------------------------------------------------+
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin
1 row in set (0.00 sec)
```

Expand Down
29 changes: 11 additions & 18 deletions sql-statements/sql-statement-show-indexes.md
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Expand Up @@ -10,25 +10,14 @@ aliases: ['/docs-cn/dev/sql-statements/sql-statement-show-indexes/','/docs-cn/de

## 语法图

**ShowIndexStmt:**
```ebnf+diagram
ShowIndexStmt ::=
"SHOW" ( "INDEX" | "INDEXES" | "KEYS" ) ("FROM" | "IN" ) TableName (("FROM" | "IN") SchemaName )? ShowLikeOrWhereOpt?

![ShowIndexStmt](/media/sqlgram/ShowIndexStmt.png)

**ShowIndexKwd:**

![ShowIndexKwd](/media/sqlgram/ShowIndexKwd.png)

**FromOrIn:**

![FromOrIn](/media/sqlgram/FromOrIn.png)

**TableName:**

![TableName](/media/sqlgram/TableName.png)

**ShowLikeOrWhereOpt:**

![ShowLikeOrWhereOpt](/media/sqlgram/ShowLikeOrWhereOpt.png)
ShowLikeOrWhere ::=
"LIKE" SimpleExpr
| "WHERE" Expression
```

## 示例

Expand Down Expand Up @@ -99,3 +88,7 @@ SHOW KEYS FROM t1;
* [SHOW CREATE TABLE](/sql-statements/sql-statement-show-create-table.md)
* [DROP INDEX](/sql-statements/sql-statement-drop-index.md)
* [CREATE INDEX](/sql-statements/sql-statement-create-index.md)
* [`information_schema.TIDB_INDEXES`](/information-schema/information-schema-tidb-indexes.md)
* [`information_schema.TIDB_INDEX_USAGE`](/information-schema/information-schema-tidb-index-usage.md)
* [`information_schema.KEY_COLUMN_USAGE`](/information-schema/information-schema-key-column-usage.md)
* [`sys.schema_unused_indexes`](/sys-schema/sys-schema-unused-indexes.md)
25 changes: 12 additions & 13 deletions sql-statements/sql-statement-show-table-next-rowid.md
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Expand Up @@ -8,20 +8,17 @@ aliases: ['/docs-cn/dev/sql-statements/sql-statement-show-table-next-rowid/']

`SHOW TABLE NEXT_ROW_ID` 语句用于显示用户表中某些特殊列的详情，主要包含以下几种类型：

* TiDB 创建的 `AUTO_INCREMENT` 类型列，即 `_tidb_rowid` 列
* TiDB 创建的 [`AUTO_INCREMENT`](/auto-increment.md) 类型列，即 `_tidb_rowid` 列
* 用户创建的 `AUTO_INCREMENT` 类型列
* 用户创建的 [`AUTO_RANDOM`](/auto-random.md) 类型列
* 用户创建的 [`SEQUENCE`](/sql-statements/sql-statement-create-sequence.md) 对象信息

## 语法图

**ShowTableNextRowIDStmt:**

![ShowTableNextRowIDStmt](/media/sqlgram/ShowTableNextRowIDStmt.png)

**TableName:**

![TableName](/media/sqlgram/TableName.png)
```ebnf+diagram
ShowTableNextRowIDStmt ::=
"SHOW" "TABLE" (SchemaName ".")? TableName "NEXT_ROW_ID"
```

## 示例

Expand All @@ -30,12 +27,12 @@ aliases: ['/docs-cn/dev/sql-statements/sql-statement-show-table-next-rowid/']
{{< copyable "sql" >}}

```sql
create table t(a int);
CREATE TABLE t(a int);
Query OK, 0 rows affected (0.06 sec)
```

```sql
show table t next_row_id;
SHOW TABLE t NEXT_ROW_ID;
+---------+------------+-------------+--------------------+
| DB_NAME | TABLE_NAME | COLUMN_NAME | NEXT_GLOBAL_ROW_ID |
+---------+------------+-------------+--------------------+
Expand All @@ -44,16 +41,18 @@ show table t next_row_id;
1 row in set (0.00 sec)
```

下面示例中，表中写入了数据，负责写入的 TiDB Server 一次性向存储层请求了 30000 个 ID 缓存起来，NEXT_GLOBAL_ROW_ID 值为 `30001`。
下面示例中，表中写入了数据，负责写入的 TiDB Server 一次性向存储层请求了 30000 个 ID 缓存起来，NEXT_GLOBAL_ROW_ID 值为 `30001`。ID 的数量由 [`AUTO_ID_CACHE`](/auto-increment.md#auto_id_cache) 控制。

{{< copyable "sql" >}}

```sql
insert into t values (), (), ();
INSERT INTO t VALUES (), (), ();
Query OK, 3 rows affected (0.02 sec)
Records: 3 Duplicates: 0 Warnings: 0
```

```sql
show table t next_row_id;
SHOW TABLE t NEXT_ROW_ID;
+---------+------------+-------------+--------------------+
| DB_NAME | TABLE_NAME | COLUMN_NAME | NEXT_GLOBAL_ROW_ID |
+---------+------------+-------------+--------------------+
Expand Down
32 changes: 10 additions & 22 deletions sql-statements/sql-statement-show-table-regions.md
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Expand Up @@ -18,25 +18,13 @@ SHOW TABLE [table_name] INDEX [index_name] REGIONS [WhereClauseOptional];

### 语法图

**ShowTableRegionStmt:**
```ebnf+diagram
ShowTableRegionStmt ::=
"SHOW" "TABLE" TableName PartitionNameList? ("INDEX" IndexName)? "REGIONS" ("WHERE" Expression)?

![ShowTableRegionStmt](/media/sqlgram/ShowTableRegionStmt.png)

**TableName:**

![TableName](/media/sqlgram/TableName.png)

**PartitionNameListOpt:**

![PartitionNameListOpt](/media/sqlgram/PartitionNameListOpt.png)

**WhereClauseOptional:**

![WhereClauseOptional](/media/sqlgram/WhereClauseOptional.png)

**WhereClause:**

![WhereClause](/media/sqlgram/WhereClause.png)
TableName ::=
(SchemaName ".")? Identifier
```

`SHOW TABLE REGIONS` 会返回如下列：

Expand Down Expand Up @@ -152,7 +140,7 @@ SHOW TABLE t1 REGIONS;
{{< copyable "sql" >}}

```sql
show table t regions;
SHOW TABLE t REGIONS;
```

```sql
Expand All @@ -179,7 +167,7 @@ show table t regions;
{{< copyable "sql" >}}

```sql
show table t regions where leader_store_id =1;
SHOW TABLE t REGIONS WHERE leader_store_id =1;
```

```
Expand All @@ -195,7 +183,7 @@ show table t regions where leader_store_id =1;
{{< copyable "sql" >}}

```sql
split table t index name between ("a") and ("z") regions 2;
SPLIT TABLE t INDEX name BETWEEN ("a") AND ("z") REGIONS 2;
```

```
Expand All @@ -212,7 +200,7 @@ split table t index name between ("a") and ("z") regions 2;
{{< copyable "sql" >}}

```sql
show table t regions;
SHOW TABLE t REGIONS;
```

```
Expand Down
69 changes: 31 additions & 38 deletions sql-statements/sql-statement-split-region.md
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Expand Up @@ -14,33 +14,26 @@ summary: TiDB 中的 Split Region 功能可以解决表数据超过默认 Region

## 语法图

**SplitRegionStmt:**
```ebnf+diagram
SplitRegionStmt ::=
"SPLIT" SplitSyntaxOption "TABLE" TableName PartitionNameList? ("INDEX" IndexName)? SplitOption

![SplitRegionStmt](/media/sqlgram/SplitRegionStmt.png)
SplitSyntaxOption ::=
("REGION" "FOR")? "PARTITION"?

**SplitSyntaxOption:**
TableName ::=
(SchemaName ".")? Identifier

![SplitSyntaxOption](/media/sqlgram/SplitSyntaxOption.png)
PartitionNameList ::=
"PARTITION" "(" PartitionName ("," PartitionName)* ")"

**TableName:**
SplitOption ::=
("BETWEEN" RowValue "AND" RowValue "REGIONS" NUM
| "BY" RowValue ("," RowValue)* )

![TableName](/media/sqlgram/TableName.png)

**PartitionNameListOpt:**

![PartitionNameListOpt](/media/sqlgram/PartitionNameListOpt.png)

**SplitOption:**

![SplitOption](/media/sqlgram/SplitOption.png)

**RowValue:**

![RowValue](/media/sqlgram/RowValue.png)

**Int64Num:**

![Int64Num](/media/sqlgram/Int64Num.png)
RowValue ::=
"(" ValuesOpt ")"
```

## Split Region 的使用

Expand Down Expand Up @@ -78,7 +71,7 @@ Split Region 有 2 种不同的语法，具体如下：
> **注意：**
>
> 以下会话变量会影响 `SPLIT` 语句的行为，需要特别注意：
>
>
> * `tidb_wait_split_region_finish`：打散 Region 的时间可能较长，由 PD 调度以及 TiKV 的负载情况所决定。这个变量用来设置在执行 `SPLIT REGION` 语句时，是否同步等待所有 Region 都打散完成后再返回结果给客户端。默认 `1` 代表等待打散完成后再返回结果。`0` 代表不等待 Region 打散完成就返回结果。
> * `tidb_wait_split_region_timeout`：这个变量用来设置 `SPLIT REGION` 语句的执行超时时间，单位是秒，默认值是 300 秒，如果超时还未完成 `Split` 操作，就返回一个超时错误。

Expand Down Expand Up @@ -276,15 +269,15 @@ region4 [("c", "") , maxIndexValue )
{{< copyable "sql" >}}

```sql
create table t (a int,b int,index idx(a)) partition by hash(a) partitions 2;
CREATE TABLE t (a INT, b INT, INDEX idx(a)) PARTITION BY HASH(a) PARTITIONS 2;
```

此时建完表后会为每个 partition 都单独 split 一个 Region，用 `SHOW TABLE REGIONS` 语法查看该表的 Region 如下：
此时建完表后会为每个 partition 都单独 split 一个 Region，用 [`SHOW TABLE REGIONS`](/sql-statements/sql-statement-show-table-regions.md) 语法查看该表的 Region 如下：

{{< copyable "sql" >}}

```sql
show table t regions;
SHOW TABLE t REGIONS;
```

```sql
Expand All @@ -301,7 +294,7 @@ region4 [("c", "") , maxIndexValue )
{{< copyable "sql" >}}

```sql
split partition table t between (0) and (10000) regions 4;
SPLIT PARTITION TABLE t BETWEEN (0) AND (10000) REGIONS 4;
```

其中，`0` 和 `10000` 分别代表你想要打散的热点数据对应的上、下边界的 `row_id`。
Expand All @@ -315,7 +308,7 @@ region4 [("c", "") , maxIndexValue )
{{< copyable "sql" >}}

```sql
show table t regions;
SHOW TABLE t REGIONS;
```

```sql
Expand All @@ -340,7 +333,7 @@ region4 [("c", "") , maxIndexValue )
{{< copyable "sql" >}}

```sql
split partition table t index idx between (1000) and (10000) regions 2;
SPLIT PARTITION TABLE t INDEX idx BETWEEN (1000) AND (10000) REGIONS 2;
```

#### Split 单个分区的 Region 示例
Expand All @@ -352,34 +345,34 @@ region4 [("c", "") , maxIndexValue )
{{< copyable "sql" >}}

```sql
create table t ( a int, b int, index idx(b)) partition by range( a ) (
partition p1 values less than (10000),
partition p2 values less than (20000),
partition p3 values less than (MAXVALUE) );
CREATE TABLE t ( a INT, b INT, INDEX idx(b)) PARTITION BY RANGE( a ) (
PARTITION p1 VALUES LESS THAN (10000),
PARTITION p2 VALUES LESS THAN (20000),
PARTITION p3 VALUES LESS THAN (MAXVALUE) );
```

2. 如果你要将 `p1` 分区的 [0,10000] 范围内的数据预切分 2 个 Region，示例语句如下：

{{< copyable "sql" >}}

```sql
split partition table t partition (p1) between (0) and (10000) regions 2;
SPLIT PARTITION TABLE t PARTITION (p1) BETWEEN (0) AND (10000) REGIONS 2;
```

3. 如果你要将 `p2` 分区的 [10000,20000] 范围内的数据预切分 2 个 Region，示例语句如下：

{{< copyable "sql" >}}

```sql
split partition table t partition (p2) between (10000) and (20000) regions 2;
SPLIT PARTITION TABLE t PARTITION (p2) BETWEEN (10000) AND (20000) REGIONS 2;
```

4. 用 `SHOW TABLE REGIONS` 语法查看该表的 Region 如下：

{{< copyable "sql" >}}

```sql
show table t regions;
SHOW TABLE t REGIONS;
```

```sql
Expand All @@ -399,7 +392,7 @@ region4 [("c", "") , maxIndexValue )
{{< copyable "sql" >}}

```sql
split partition table t partition (p1,p2) index idx between (0) and (20000) regions 2;
SPLIT PARTITION TABLE t PARTITION (p1,p2) INDEX idx BETWEEN (0) AND (20000) REGIONS 2;
```

## pre_split_regions
Expand All @@ -419,7 +412,7 @@ region4 [("c", "") , maxIndexValue )
{{< copyable "sql" >}}

```sql
create table t (a int, b int,index idx1(a)) shard_row_id_bits = 4 pre_split_regions=2;
CREATE TABLE t (a INT, b INT, INDEX idx1(a)) SHARD_ROW_ID_BITS = 4 PRE_SPLIT_REGIONS=2;
```

该语句在建表后，会对这个表 t 预切分出 4 + 1 个 Region。4 (2^2) 个 Region 是用来存 table 的行数据的，1 个 Region 是用来存 idx1 索引的数据。
Expand Down
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