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Update lock stats docs #15075

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Update lock stats docs #15075

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Update lock stats docs
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10 changes: 10 additions & 0 deletions privilege-management.md
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Expand Up @@ -398,6 +398,14 @@ SELECT * FROM INFORMATION_SCHEMA.USER_PRIVILEGES WHERE grantee = "'root'@'%'";

需要对所操作的表拥有 `INSERT` 和 `SELECT` 权限。

### LOCK STATS

需要对所操作的表拥有 `INSERT` 和 `SELECT` 权限。

### UNLOCK STATS

需要对所操作的表拥有 `INSERT` 和 `SELECT` 权限。

### SHOW

`SHOW CREATE TABLE` 需要任意一种权限。
Expand All @@ -410,6 +418,8 @@ SELECT * FROM INFORMATION_SCHEMA.USER_PRIVILEGES WHERE grantee = "'root'@'%'";

`SHOW IMPORT JOB` 需要 `SUPER` 权限来显示属于其他用户的任务，否则只能看到当前用户创建的任务。

`SHOW STATS_LOCKED` 需要拥有 `mysql.stats_table_locked` 表的 `SELECT` 权限。

### CREATE ROLE/USER

`CREATE ROLE` 需要 `CREATE ROLE` 权限。
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117 changes: 79 additions & 38 deletions sql-statements/sql-statement-lock-stats.md
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Expand Up @@ -5,94 +5,135 @@ summary: TiDB 数据库中 LOCK STATS 的使用概况。

# LOCK STATS

`LOCK STATS` 语句用于锁定统计信息。

> **警告：**
>
> 锁定统计信息目前为实验特性，不建议在生产环境中使用。
`LOCK STATS` 语句用于锁定表或分区的统计信息，使得在锁定期间，TiDB 不会自动更新统计信息。具体行为请参见[锁定统计信息的行为说明](/statistics.md#锁定统计信息的行为说明)

## 语法图

```ebnf+diagram
LockStatsStmt ::=
'LOCK' 'STATS' TableNameList
'LOCK' 'STATS' (TableNameList) | (TableName 'PARTITION' PartitionNameList)

TableNameList ::=
TableName (',' TableName)*

TableName ::=
Identifier ( '.' Identifier )?

PartitionNameList ::=
Identifier ( ',' Identifier )*
```

## 示例

创建表 `t`，插入一些数据，在未锁定表 `t` 的统计信息的情况下成功执行 `ANALYZE` 语句。

```sql
mysql> create table t(a int, b int);
mysql> CREATE TABLE t(a INT, b INT);
Query OK, 0 rows affected (0.03 sec)

mysql> insert into t values (1,2), (3,4), (5,6), (7,8);
mysql> INSERT INTO t VALUES (1,2), (3,4), (5,6), (7,8);
Query OK, 4 rows affected (0.00 sec)
Records: 4 Duplicates: 0 Warnings: 0

mysql> analyze table t;
mysql> ANALYZE TABLE t;
Query OK, 0 rows affected, 1 warning (0.02 sec)

mysql> show warnings;
+-------+------+-----------------------------------------------------------------+
| Level | Code | Message |
+-------+------+-----------------------------------------------------------------+
| Note | 1105 | Analyze use auto adjusted sample rate 1.000000 for table test.t |
+-------+------+-----------------------------------------------------------------+
mysql> SHOW WARNINGS;
+-------+------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Level | Code | Message |
+-------+------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Note | 1105 | Analyze use auto adjusted sample rate 1.000000 for table test.t, reason to use this rate is "Row count in stats_meta is much smaller compared with the row count got by PD, use min(1, 15000/4) as the sample-rate=1" |
+-------+------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
```

锁定表 `t` 的统计信息，执行 `ANALYZE` 语句，warning 提示跳过对表 `t` 的 `ANALYZE`。

```sql
mysql> lock stats t;
mysql> LOCK STATS t;
Query OK, 0 rows affected (0.00 sec)

mysql> show stats_locked;
mysql> SHOW STATS_LOCKED;
+---------+------------+----------------+--------+
| Db_name | Table_name | Partition_name | Status |
+---------+------------+----------------+--------+
| test | t | | locked |
+---------+------------+----------------+--------+
1 row in set (0.01 sec)

mysql> analyze table t;
mysql> ANALYZE TABLE t;
Query OK, 0 rows affected, 2 warnings (0.00 sec)

mysql> show warnings;
+---------+------+-----------------------------------------------------------------+
| Level | Code | Message |
+---------+------+-----------------------------------------------------------------+
| Note | 1105 | Analyze use auto adjusted sample rate 1.000000 for table test.t |
| Warning | 1105 | skip analyze locked table: t |
+---------+------+-----------------------------------------------------------------+
mysql> SHOW WARNINGS;
+---------+------+-----------------------------------------------------------------------------------------------------------------------------------------+
| Level | Code | Message |
+---------+------+-----------------------------------------------------------------------------------------------------------------------------------------+
| Note | 1105 | Analyze use auto adjusted sample rate 1.000000 for table test.t, reason to use this rate is "use min(1, 110000/8) as the sample-rate=1" |
| Warning | 1105 | skip analyze locked table: test.t |
+---------+------+-----------------------------------------------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)
```

解锁表 `t` 的统计信息，成功执行 `ANALYZE` 语句。
解锁统计信息请参考 [UNLOCK STATS](/sql-statements/sql-statement-unlock-stats.md)。
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另外，你也可以通过 `LOCK STATS` 语句锁定分区的统计信息。用例如下：

创建分区表 `t`，插入一些数据，在未锁定分区 `p1` 的统计信息的情况下成功执行 `ANALYZE` 语句。

```sql
mysql> unlock stats t;
Query OK, 0 rows affected (0.01 sec)

mysql> analyze table t;
Query OK, 0 rows affected, 1 warning (0.03 sec)

mysql> show warnings;
+-------+------+-----------------------------------------------------------------+
| Level | Code | Message |
+-------+------+-----------------------------------------------------------------+
| Note | 1105 | Analyze use auto adjusted sample rate 1.000000 for table test.t |
+-------+------+-----------------------------------------------------------------+
mysql> CREATE TABLE t(a INT, b INT) PARTITION BY RANGE (a) (PARTITION p0 VALUES LESS THAN (10), PARTITION p1 VALUES LESS THAN (20), PARTITION p2 VALUES LESS THAN (30));
Query OK, 0 rows affected (0.03 sec)

mysql> INSERT INTO t VALUES (1,2), (3,4), (5,6), (7,8);
Query OK, 4 rows affected (0.00 sec)
Records: 4 Duplicates: 0 Warnings: 0

mysql> ANALYZE TABLE t;
Query OK, 0 rows affected, 1 warning (0.02 sec)
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mysql> SHOW WARNINGS;
+---------+------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Level | Code | Message |
+---------+------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Warning | 1105 | disable dynamic pruning due to t has no global stats |
| Note | 1105 | Analyze use auto adjusted sample rate 1.000000 for table test.t's partition p0, reason to use this rate is "Row count in stats_meta is much smaller compared with the row count got by PD, use min(1, 15000/4) as the sample-rate=1" |
| Warning | 1105 | disable dynamic pruning due to t has no global stats |
| Note | 1105 | Analyze use auto adjusted sample rate 1.000000 for table test.t's partition p1, reason to use this rate is "TiDB assumes that the table is empty, use sample-rate=1" |
| Warning | 1105 | disable dynamic pruning due to t has no global stats |
| Note | 1105 | Analyze use auto adjusted sample rate 1.000000 for table test.t's partition p2, reason to use this rate is "TiDB assumes that the table is empty, use sample-rate=1" |
+---------+------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
6 rows in set (0.01 sec)
```

锁定分区 `p1` 的统计信息，执行 `ANALYZE` 语句，warning 提示跳过对分区 `p1` 的 `ANALYZE`。

```sql
mysql> LOCK STATS t PARTITION p1;
Query OK, 0 rows affected (0.00 sec)

mysql> SHOW STATS_LOCKED;
+---------+------------+----------------+--------+
| Db_name | Table_name | Partition_name | Status |
+---------+------------+----------------+--------+
| test | t | p1 | locked |
+---------+------------+----------------+--------+
1 row in set (0.00 sec)

mysql> ANALYZE TABLE t PARTITION p1;
Query OK, 0 rows affected, 2 warnings (0.01 sec)

mysql> SHOW WARNINGS;
+---------+------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Level | Code | Message |
+---------+------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Note | 1105 | Analyze use auto adjusted sample rate 1.000000 for table test.t's partition p1, reason to use this rate is "TiDB assumes that the table is empty, use sample-rate=1" |
| Warning | 1105 | skip analyze locked table: test.t partition (p1) |
+---------+------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)
```

解锁统计信息请参考 [UNLOCK STATS](/sql-statements/sql-statement-unlock-stats.md)。

## MySQL 兼容性

该语句是 TiDB 对 MySQL 语法的扩展。
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58 changes: 12 additions & 46 deletions sql-statements/sql-statement-show-stats-locked.md
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Expand Up @@ -7,10 +7,6 @@ summary: TiDB 数据库中 SHOW STATS_LOCKED 的使用概况。

`SHOW STATS_LOCKED` 语句显示统计信息被锁定的表。

> **警告：**
>
> 锁定统计信息目前为实验特性，不建议在生产环境中使用。

## 语法图

```ebnf+diagram
Expand All @@ -24,68 +20,38 @@ ShowLikeOrWhereOpt ::= 'LIKE' SimpleExpr | 'WHERE' Expression
创建表 `t`，插入一些数据，在未锁定表 `t` 的统计信息的情况下成功执行 `ANALYZE` 语句。

```sql
mysql> create table t(a int, b int);
mysql> CREATE TABLE t(a INT, b INT);
Query OK, 0 rows affected (0.03 sec)

mysql> insert into t values (1,2), (3,4), (5,6), (7,8);
mysql> INSERT INTO t VALUES (1,2), (3,4), (5,6), (7,8);
Query OK, 4 rows affected (0.00 sec)
Records: 4 Duplicates: 0 Warnings: 0

mysql> analyze table t;
mysql> ANALYZE TABLE t;
Query OK, 0 rows affected, 1 warning (0.02 sec)

mysql> show warnings;
+-------+------+-----------------------------------------------------------------+
| Level | Code | Message |
+-------+------+-----------------------------------------------------------------+
| Note | 1105 | Analyze use auto adjusted sample rate 1.000000 for table test.t |
+-------+------+-----------------------------------------------------------------+
mysql> SHOW WARNINGS;
+-------+------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Level | Code | Message |
+-------+------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Note | 1105 | Analyze use auto adjusted sample rate 1.000000 for table test.t, reason to use this rate is "Row count in stats_meta is much smaller compared with the row count got by PD, use min(1, 15000/4) as the sample-rate=1" |
+-------+------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
```

锁定表 `t` 的统计信息，执行 `ANALYZE` 语句，使用 `SHOW STATS_LOCKED` 可查看表 `t` 的统计信息已被锁定。warning 提示跳过对表 `t` 的 `ANALYZE`。
锁定表 `t` 的统计信息，执行 `SHOW STATS_LOCKED` 语句，显示表 `t` 的统计信息被锁定。

```sql
mysql> lock stats t;
mysql> LOCK STATS t;
Query OK, 0 rows affected (0.00 sec)

mysql> show stats_locked;
mysql> SHOW STATS_LOCKED;
+---------+------------+----------------+--------+
| Db_name | Table_name | Partition_name | Status |
+---------+------------+----------------+--------+
| test | t | | locked |
+---------+------------+----------------+--------+
1 row in set (0.01 sec)

mysql> analyze table t;
Query OK, 0 rows affected, 2 warnings (0.00 sec)

mysql> show warnings;
+---------+------+-----------------------------------------------------------------+
| Level | Code | Message |
+---------+------+-----------------------------------------------------------------+
| Note | 1105 | Analyze use auto adjusted sample rate 1.000000 for table test.t |
| Warning | 1105 | skip analyze locked table: t |
+---------+------+-----------------------------------------------------------------+
2 rows in set (0.00 sec)
```

解锁表 `t` 的统计信息，成功执行 `ANALYZE` 语句。

```sql
mysql> unlock stats t;
Query OK, 0 rows affected (0.01 sec)

mysql> analyze table t;
Query OK, 0 rows affected, 1 warning (0.03 sec)

mysql> show warnings;
+-------+------+-----------------------------------------------------------------+
| Level | Code | Message |
+-------+------+-----------------------------------------------------------------+
| Note | 1105 | Analyze use auto adjusted sample rate 1.000000 for table test.t |
+-------+------+-----------------------------------------------------------------+
1 row in set (0.00 sec)
```

## MySQL 兼容性
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