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ADD COLUMN
ADD INDEX
ADMIN
ADMIN CANCEL DDL
ADMIN CHECKSUM TABLE
ADMIN CHECK [TABLE|INDEX]
ADMIN SHOW DDL [JOBS|QUERIES]
ALTER DATABASE
ALTER INDEX
ALTER INSTANCE
ALTER TABLE
ALTER USER
ANALYZE TABLE
BACKUP
BEGIN
CHANGE COLUMN
CHANGE DRAINER
CHANGE PUMP
COMMIT
CREATE [GLOBAL|SESSION] BINDING
CREATE DATABASE
CREATE INDEX
CREATE ROLE
CREATE SEQUENCE
CREATE TABLE LIKE
CREATE TABLE
CREATE USER
CREATE VIEW
DEALLOCATE
DELETE
DESC
DESCRIBE
DO
DROP [GLOBAL|SESSION] BINDING
DROP COLUMN
DROP DATABASE
DROP INDEX
DROP ROLE
DROP SEQUENCE
DROP STATS
DROP TABLE
DROP USER
DROP VIEW
EXECUTE
EXPLAIN ANALYZE
EXPLAIN
FLASHBACK TABLE
FLUSH PRIVILEGES
FLUSH STATUS
FLUSH TABLES
GRANT <privileges>
GRANT <role>
INSERT
KILL [TIDB]
LOAD DATA
LOAD STATS
MODIFY COLUMN
PREPARE
RECOVER TABLE
RENAME INDEX
RENAME TABLE
REPLACE
RESTORE
REVOKE <privileges>
REVOKE <role>
ROLLBACK
SELECT
SET DEFAULT ROLE
SET [NAMES|CHARACTER SET]
SET PASSWORD
SET ROLE
SET TRANSACTION
SET [GLOBAL|SESSION] <variable>
SHOW [BACKUPS|RESTORES]
SHOW ANALYZE STATUS
SHOW [GLOBAL|SESSION] BINDINGS
SHOW BUILTINS
SHOW CHARACTER SET
SHOW COLLATION
SHOW [FULL] COLUMNS FROM
SHOW CONFIG
SHOW CREATE SEQUENCE
SHOW CREATE TABLE
SHOW CREATE USER
SHOW DATABASES
SHOW DRAINER STATUS
SHOW ENGINES
SHOW ERRORS
SHOW [FULL] FIELDS FROM
SHOW GRANTS
SHOW INDEX [FROM|IN]
SHOW INDEXES [FROM|IN]
SHOW KEYS [FROM|IN]
SHOW MASTER STATUS
SHOW PLUGINS
SHOW PRIVILEGES
SHOW [FULL] PROCESSSLIST
SHOW PROFILES
SHOW PUMP STATUS
SHOW SCHEMAS
SHOW STATS_HEALTHY
SHOW STATS_HISTOGRAMS
SHOW STATS_META
SHOW STATUS
SHOW TABLE NEXT_ROW_ID
SHOW TABLE REGIONS
SHOW TABLE STATUS
SHOW [FULL] TABLES
SHOW [GLOBAL|SESSION] VARIABLES
SHOW WARNINGS
SHUTDOWN
SPLIT REGION
START TRANSACTION
TABLE
TRACE
TRUNCATE
UPDATE
USE
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mysql
- INFORMATION_SCHEMA
- Overview
ANALYZE_STATUS
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TIDB_HOT_REGIONS
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- v5.0
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- v1.0
- 术语表
TABLES
TABLES
表提供了数据库里关于表的信息。
USE information_schema;
DESC tables;
+---------------------------+---------------+------+------+----------+-------+
| Field | Type | Null | Key | Default | Extra |
+---------------------------+---------------+------+------+----------+-------+
| TABLE_CATALOG | varchar(512) | YES | | NULL | |
| TABLE_SCHEMA | varchar(64) | YES | | NULL | |
| TABLE_NAME | varchar(64) | YES | | NULL | |
| TABLE_TYPE | varchar(64) | YES | | NULL | |
| ENGINE | varchar(64) | YES | | NULL | |
| VERSION | bigint(21) | YES | | NULL | |
| ROW_FORMAT | varchar(10) | YES | | NULL | |
| TABLE_ROWS | bigint(21) | YES | | NULL | |
| AVG_ROW_LENGTH | bigint(21) | YES | | NULL | |
| DATA_LENGTH | bigint(21) | YES | | NULL | |
| MAX_DATA_LENGTH | bigint(21) | YES | | NULL | |
| INDEX_LENGTH | bigint(21) | YES | | NULL | |
| DATA_FREE | bigint(21) | YES | | NULL | |
| AUTO_INCREMENT | bigint(21) | YES | | NULL | |
| CREATE_TIME | datetime | YES | | NULL | |
| UPDATE_TIME | datetime | YES | | NULL | |
| CHECK_TIME | datetime | YES | | NULL | |
| TABLE_COLLATION | varchar(32) | NO | | utf8_bin | |
| CHECKSUM | bigint(21) | YES | | NULL | |
| CREATE_OPTIONS | varchar(255) | YES | | NULL | |
| TABLE_COMMENT | varchar(2048) | YES | | NULL | |
| TIDB_TABLE_ID | bigint(21) | YES | | NULL | |
| TIDB_ROW_ID_SHARDING_INFO | varchar(255) | YES | | NULL | |
+---------------------------+---------------+------+------+----------+-------+
23 rows in set (0.00 sec)
SELECT * FROM tables WHERE table_schema='mysql' AND table_name='user'\G
*************************** 1. row ***************************
TABLE_CATALOG: def
TABLE_SCHEMA: mysql
TABLE_NAME: user
TABLE_TYPE: BASE TABLE
ENGINE: InnoDB
VERSION: 10
ROW_FORMAT: Compact
TABLE_ROWS: 0
AVG_ROW_LENGTH: 0
DATA_LENGTH: 0
MAX_DATA_LENGTH: 0
INDEX_LENGTH: 0
DATA_FREE: 0
AUTO_INCREMENT: NULL
CREATE_TIME: 2020-07-05 09:25:51
UPDATE_TIME: NULL
CHECK_TIME: NULL
TABLE_COLLATION: utf8mb4_bin
CHECKSUM: NULL
CREATE_OPTIONS:
TABLE_COMMENT:
TIDB_TABLE_ID: 5
TIDB_ROW_ID_SHARDING_INFO: NULL
1 row in set (0.00 sec)
下列语句是等价的:
SELECT table_name FROM INFORMATION_SCHEMA.TABLES
WHERE table_schema = 'db_name'
[AND table_name LIKE 'wild']
SHOW TABLES
FROM db_name
[LIKE 'wild']
TABLES
表各列字段含义如下:
TABLE_CATALOG
:表所属的目录的名称。该值始终为def
。TABLE_SCHEMA
:表所属数据库的名称。TABLE_NAME
:表的名称。TABLE_TYPE
:表的类型。ENGINE
:存储引擎类型。该值暂为 ‘InnoDB’。VERSION
:版本,默认值为 10。ROW_FORMAT
:行格式。该值暂为 ‘Compact’。TABLE_ROWS
:统计信息中该表所存的行数。AVG_ROW_LENGTH
:该表中所存数据的平均行长度。平均行长度 = DATA_LENGTH / 统计信息中的行数。DATA_LENGTH
:数据长度。数据长度 = 统计信息中的行数 × 元组各列存储长度和,这里尚未考虑 TiKV 的副本数。MAX_DATA_LENGTH
:最大数据长度。该值暂为 0,表示没有最大数据长度的限制。INDEX_LENGTH
:索引长度。索引长度 = 统计信息中的行数 × 索引元组各列长度和,这里尚未考虑 TiKV 的副本数。DATA_FREE
:空间碎片。该值暂为 0。AUTO_INCREMENT
:该表中自增主键自动增量的当前值。CREATE_TIME
:该表的创建时间。UPDATE_TIME
:该表的更新时间。CHECK_TIME
:该表的检查时间。TABLE_COLLATION
:该表的字符校验编码集。CHECKSUM
:校验和。CREATE_OPTIONS
:创建选项。TABLE_COMMENT
:表的注释、备注。
表中的信息大部分定义自 MySQL,只有两列是 TiDB 新增的:
TIDB_TABLE_ID
:标识表的内部 ID,该 ID 在一个 TiDB 集群内部唯一。TIDB_ROW_ID_SHARDING_INFO
:标识表的 Sharding 类型,可能的值为:"NOT_SHARDED"
:表未被 Shard。"NOT_SHARDED(PK_IS_HANDLE)"
:一个定义了整型主键的表未被 Shard。"PK_AUTO_RANDOM_BITS={bit_number}"
:一个定义了整型主键的表由于定义了AUTO_RANDOM
而被 Shard。"SHARD_BITS={bit_number}"
:表使用SHARD_ROW_ID_BITS={bit_number}
进行了 Shard。- NULL:表属于系统表或 View,无法被 Shard。
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