• Information Schema
    • ANALYZE_STATUS Table
    • CHARACTER_SETS Table
    • COLLATIONS Table
    • COLLATION_CHARACTER_SET_APPLICABILITY Table
    • COLUMNS Table
    • ENGINES Table
    • KEY_COLUMN_USAGE Table
    • PROCESSLIST Table
    • SCHEMATA Table
    • SESSION_VARIABLES Table
    • SLOW_QUERY Table
    • STATISTICS Table
    • TABLES Table
    • TABLE_CONSTRAINTS Table
    • TIDB_HOT_REGIONS Table
    • TIDB_INDEXES Table
    • TIKV_REGION_PEERS Table
    • TIKV_REGION_STATUS Table
    • TIKV_STORE_STATUS Table
    • USER_PRIVILEGES Table
    • VIEWS Table
    • 不支持的 Information Schema 表

    Information Schema

    为了和 MySQL 保持兼容，TiDB 支持很多 INFORMATION_SCHEMA 表，其中有不少表都支持相应的 SHOW 命令。查询 INFORMATION_SCHEMA 表也为表的连接操作提供了可能。

    ANALYZE_STATUS Table

    ANALYZE_STATUS 表提供正在执行的收集统计信息的任务以及有限条历史任务记录。

    1. mysql> select * from `ANALYZE_STATUS`
    2. +--------------+------------+----------------+-------------------+----------------+---------------------+----------+
    3. | TABLE_SCHEMA | TABLE_NAME | PARTITION_NAME | JOB_INFO          | PROCESSED_ROWS | START_TIME          | STATE    |
    4. +--------------+------------+----------------+-------------------+----------------+---------------------+----------+
    5. | test         | t          |                | analyze index idx | 2              | 2019-06-21 19:51:14 | finished |
    6. | test         | t          |                | analyze columns   | 2              | 2019-06-21 19:51:14 | finished |
    7. | test         | t1         | p0             | analyze columns   | 0              | 2019-06-21 19:51:15 | finished |
    8. | test         | t1         | p3             | analyze columns   | 0              | 2019-06-21 19:51:15 | finished |
    9. | test         | t1         | p1             | analyze columns   | 0              | 2019-06-21 19:51:15 | finished |
    10. | test         | t1         | p2             | analyze columns   | 1              | 2019-06-21 19:51:15 | finished |
    11. +--------------+------------+----------------+-------------------+----------------+---------------------+----------+
    12. 6 rows in set

    CHARACTER_SETS Table

    CHARACTER_SETS 表提供字符集相关的信息。TiDB 目前仅支持部分字符集。

    1. mysql> SELECT * FROM character_sets;
    2. +--------------------+----------------------+---------------+--------+
    3. | CHARACTER_SET_NAME | DEFAULT_COLLATE_NAME | DESCRIPTION   | MAXLEN |
    4. +--------------------+----------------------+---------------+--------+
    5. | utf8               | utf8_bin             | UTF-8 Unicode |      3 |
    6. | utf8mb4            | utf8mb4_bin          | UTF-8 Unicode |      4 |
    7. | ascii              | ascii_bin            | US ASCII      |      1 |
    8. | latin1             | latin1_bin           | Latin1        |      1 |
    9. | binary             | binary               | binary        |      1 |
    10. +--------------------+----------------------+---------------+--------+
    11. 5 rows in set (0.00 sec)

    COLLATIONS Table

    COLLATIONS 表提供了 CHARACTER_SETS 表中字符集对应的排序规则列表。TiDB 当前仅支持二进制排序规则，包含该表仅为兼容 MySQL。

    1. mysql> SELECT * FROM collations WHERE character_set_name='utf8mb4';
    2. +------------------------+--------------------+------+------------+-------------+---------+
    3. | COLLATION_NAME         | CHARACTER_SET_NAME | ID   | IS_DEFAULT | IS_COMPILED | SORTLEN |
    4. +------------------------+--------------------+------+------------+-------------+---------+
    5. | utf8mb4_general_ci     | utf8mb4            |   45 | Yes        | Yes         |       1 |
    6. | utf8mb4_bin            | utf8mb4            |   46 |            | Yes         |       1 |
    7. | utf8mb4_unicode_ci     | utf8mb4            |  224 |            | Yes         |       1 |
    8. | utf8mb4_icelandic_ci   | utf8mb4            |  225 |            | Yes         |       1 |
    9. | utf8mb4_latvian_ci     | utf8mb4            |  226 |            | Yes         |       1 |
    10. | utf8mb4_romanian_ci    | utf8mb4            |  227 |            | Yes         |       1 |
    11. | utf8mb4_slovenian_ci   | utf8mb4            |  228 |            | Yes         |       1 |
    12. | utf8mb4_polish_ci      | utf8mb4            |  229 |            | Yes         |       1 |
    13. | utf8mb4_estonian_ci    | utf8mb4            |  230 |            | Yes         |       1 |
    14. | utf8mb4_spanish_ci     | utf8mb4            |  231 |            | Yes         |       1 |
    15. | utf8mb4_swedish_ci     | utf8mb4            |  232 |            | Yes         |       1 |
    16. | utf8mb4_turkish_ci     | utf8mb4            |  233 |            | Yes         |       1 |
    17. | utf8mb4_czech_ci       | utf8mb4            |  234 |            | Yes         |       1 |
    18. | utf8mb4_danish_ci      | utf8mb4            |  235 |            | Yes         |       1 |
    19. | utf8mb4_lithuanian_ci  | utf8mb4            |  236 |            | Yes         |       1 |
    20. | utf8mb4_slovak_ci      | utf8mb4            |  237 |            | Yes         |       1 |
    21. | utf8mb4_spanish2_ci    | utf8mb4            |  238 |            | Yes         |       1 |
    22. | utf8mb4_roman_ci       | utf8mb4            |  239 |            | Yes         |       1 |
    23. | utf8mb4_persian_ci     | utf8mb4            |  240 |            | Yes         |       1 |
    24. | utf8mb4_esperanto_ci   | utf8mb4            |  241 |            | Yes         |       1 |
    25. | utf8mb4_hungarian_ci   | utf8mb4            |  242 |            | Yes         |       1 |
    26. | utf8mb4_sinhala_ci     | utf8mb4            |  243 |            | Yes         |       1 |
    27. | utf8mb4_german2_ci     | utf8mb4            |  244 |            | Yes         |       1 |
    28. | utf8mb4_croatian_ci    | utf8mb4            |  245 |            | Yes         |       1 |
    29. | utf8mb4_unicode_520_ci | utf8mb4            |  246 |            | Yes         |       1 |
    30. | utf8mb4_vietnamese_ci  | utf8mb4            |  247 |            | Yes         |       1 |
    31. +------------------------+--------------------+------+------------+-------------+---------+
    32. 26 rows in set (0.00 sec)

    COLLATION_CHARACTER_SET_APPLICABILITY Table

    COLLATION_CHARACTER_SET_APPLICABILITY 表将排序规则映射至适用的字符集名称。和 COLLATIONS 表一样，包含此表也是为了兼容 MySQL。

    1. mysql> SELECT * FROM collation_character_set_applicability WHERE character_set_name='utf8mb4';
    2. +------------------------+--------------------+
    3. | COLLATION_NAME         | CHARACTER_SET_NAME |
    4. +------------------------+--------------------+
    5. | utf8mb4_general_ci     | utf8mb4            |
    6. | utf8mb4_bin            | utf8mb4            |
    7. | utf8mb4_unicode_ci     | utf8mb4            |
    8. | utf8mb4_icelandic_ci   | utf8mb4            |
    9. | utf8mb4_latvian_ci     | utf8mb4            |
    10. | utf8mb4_romanian_ci    | utf8mb4            |
    11. | utf8mb4_slovenian_ci   | utf8mb4            |
    12. | utf8mb4_polish_ci      | utf8mb4            |
    13. | utf8mb4_estonian_ci    | utf8mb4            |
    14. | utf8mb4_spanish_ci     | utf8mb4            |
    15. | utf8mb4_swedish_ci     | utf8mb4            |
    16. | utf8mb4_turkish_ci     | utf8mb4            |
    17. | utf8mb4_czech_ci       | utf8mb4            |
    18. | utf8mb4_danish_ci      | utf8mb4            |
    19. | utf8mb4_lithuanian_ci  | utf8mb4            |
    20. | utf8mb4_slovak_ci      | utf8mb4            |
    21. | utf8mb4_spanish2_ci    | utf8mb4            |
    22. | utf8mb4_roman_ci       | utf8mb4            |
    23. | utf8mb4_persian_ci     | utf8mb4            |
    24. | utf8mb4_esperanto_ci   | utf8mb4            |
    25. | utf8mb4_hungarian_ci   | utf8mb4            |
    26. | utf8mb4_sinhala_ci     | utf8mb4            |
    27. | utf8mb4_german2_ci     | utf8mb4            |
    28. | utf8mb4_croatian_ci    | utf8mb4            |
    29. | utf8mb4_unicode_520_ci | utf8mb4            |
    30. | utf8mb4_vietnamese_ci  | utf8mb4            |
    31. +------------------------+--------------------+
    32. 26 rows in set (0.00 sec)

    COLUMNS Table

    COLUMNS 表提供了表的所有列的信息。

    1. mysql> CREATE TABLE test.t1 (a int);
    2. 1 row in set (0.01 sec)
    3. mysql> SELECT * FROM information_schema.columns WHERE table_schema='test' AND TABLE_NAME='t1'\G
    4. *************************** 1. row ***************************
    5.            TABLE_CATALOG: def
    6.             TABLE_SCHEMA: test
    7.               TABLE_NAME: t1
    8.              COLUMN_NAME: a
    9.         ORDINAL_POSITION: 1
    10.           COLUMN_DEFAULT: NULL
    11.              IS_NULLABLE: YES
    12.                DATA_TYPE: int
    13. CHARACTER_MAXIMUM_LENGTH: NULL
    14.   CHARACTER_OCTET_LENGTH: NULL
    15.        NUMERIC_PRECISION: 11
    16.            NUMERIC_SCALE: 0
    17.       DATETIME_PRECISION: NULL
    18.       CHARACTER_SET_NAME: NULL
    19.           COLLATION_NAME: NULL
    20.              COLUMN_TYPE: int(11)
    21.               COLUMN_KEY: 
    22.                    EXTRA: 
    23.               PRIVILEGES: select,insert,update,references
    24.           COLUMN_COMMENT: 
    25.    GENERATION_EXPRESSION: 
    26. 1 row in set (0.01 sec)

    对应的 SHOW 语句如下：

    1. mysql> SHOW COLUMNS FROM t1 FROM test;
    2. +-------+---------+------+------+---------+-------+
    3. | Field | Type    | Null | Key  | Default | Extra |
    4. +-------+---------+------+------+---------+-------+
    5. | a     | int(11) | YES  |      | NULL    |       |
    6. +-------+---------+------+------+---------+-------+
    7. 1 row in set (0.00 sec)

    ENGINES Table

    ENGINES 表提供了关于存储引擎的信息。从和 MySQL 兼容性上考虑，TiDB 会一直将 InnoDB 描述为唯一支持的引擎。

    1. mysql> SELECT * FROM engines\G
    2. *************************** 1. row ***************************
    3.       ENGINE: InnoDB
    4.      SUPPORT: DEFAULT
    5.      COMMENT: Supports transactions, row-level locking, and foreign keys
    6. TRANSACTIONS: YES
    7.           XA: YES
    8.   SAVEPOINTS: YES
    9. 1 row in set (0.00 sec)

    KEY_COLUMN_USAGE Table

    KEY_COLUMN_USAGE 表描述了列的键约束，比如主键约束。

    1. mysql> SELECT * FROM key_column_usage WHERE table_schema='mysql' and table_name='user'\G
    2. *************************** 1. row ***************************
    3.            CONSTRAINT_CATALOG: def
    4.             CONSTRAINT_SCHEMA: mysql
    5.               CONSTRAINT_NAME: PRIMARY
    6.                 TABLE_CATALOG: def
    7.                  TABLE_SCHEMA: mysql
    8.                    TABLE_NAME: user
    9.                   COLUMN_NAME: Host
    10.              ORDINAL_POSITION: 1
    11. POSITION_IN_UNIQUE_CONSTRAINT: NULL
    12.       REFERENCED_TABLE_SCHEMA: NULL
    13.         REFERENCED_TABLE_NAME: NULL
    14.        REFERENCED_COLUMN_NAME: NULL
    15. *************************** 2. row ***************************
    16.            CONSTRAINT_CATALOG: def
    17.             CONSTRAINT_SCHEMA: mysql
    18.               CONSTRAINT_NAME: PRIMARY
    19.                 TABLE_CATALOG: def
    20.                  TABLE_SCHEMA: mysql
    21.                    TABLE_NAME: user
    22.                   COLUMN_NAME: User
    23.              ORDINAL_POSITION: 2
    24. POSITION_IN_UNIQUE_CONSTRAINT: NULL
    25.       REFERENCED_TABLE_SCHEMA: NULL
    26.         REFERENCED_TABLE_NAME: NULL
    27.        REFERENCED_COLUMN_NAME: NULL
    28. 2 rows in set (0.00 sec)

    PROCESSLIST Table

    PROCESSLIST 和 show processlist 的功能一样，都是查看当前正在处理的请求。

    PROCESSLIST 表会比 show processlist 多一个 MEM 列，MEM 是指正在处理的请求已使用的内存，单位是 byte。

    1. +----+------+------+--------------------+---------+------+-------+---------------------------+-----+
    2. | ID | USER | HOST | DB                 | COMMAND | TIME | STATE | INFO                      | MEM |
    3. +----+------+------+--------------------+---------+------+-------+---------------------------+-----+
    4. | 1  | root | ::1  | INFORMATION_SCHEMA | Query   | 0    | 2     | select * from PROCESSLIST | 0   |
    5. +----+------+------+--------------------+---------+------+-------+---------------------------+-----+

    SCHEMATA Table

    SCHEMATA 表提供了关于数据库的信息。表中的数据与 SHOW DATABASES 语句的执行结果等价。

    1. mysql> SELECT * FROM schemata; 
    2. +--------------+--------------------+----------------------------+------------------------+----------+ 
    3. | CATALOG_NAME | SCHEMA_NAME        | DEFAULT_CHARACTER_SET_NAME | DEFAULT_COLLATION_NAME | SQL_PATH | 
    4. +--------------+--------------------+----------------------------+------------------------+----------+ 
    5. | def          | INFORMATION_SCHEMA | utf8mb4                    | utf8mb4_bin            | NULL     | 
    6. | def          | mynewdb            | utf8mb4                    | utf8mb4_bin            | NULL     |
    7. | def          | mysql              | utf8mb4                    | utf8mb4_bin            | NULL     | 
    8. | def          | PERFORMANCE_SCHEMA | utf8mb4                    | utf8mb4_bin            | NULL     | 
    9. | def          | test               | utf8mb4                    | utf8mb4_bin            | NULL     | 
    10. +--------------+--------------------+----------------------------+------------------------+----------+ 
    11. 5 rows in set (0.00 sec)

    SESSION_VARIABLES Table

    SESSION_VARIABLES 表提供了关于 session 变量的信息。表中的数据跟 SHOW SESSION VARIABLES 语句执行结果类似。

    1. mysql> SELECT * FROM session_variables LIMIT 10;
    2. +----------------------------------+----------------------+
    3. | VARIABLE_NAME                    | VARIABLE_VALUE       |
    4. +----------------------------------+----------------------+
    5. | max_write_lock_count             | 18446744073709551615 |
    6. | server_id_bits                   | 32                   |
    7. | net_read_timeout                 | 30                   |
    8. | innodb_online_alter_log_max_size | 134217728            |
    9. | innodb_optimize_fulltext_only    | OFF                  |
    10. | max_join_size                    | 18446744073709551615 |
    11. | innodb_read_io_threads           | 4                    |
    12. | session_track_gtids              | OFF                  |
    13. | have_ssl                         | DISABLED             |
    14. | max_binlog_cache_size            | 18446744073709547520 |
    15. +----------------------------------+----------------------+
    16. 10 rows in set (0.00 sec)

    SLOW_QUERY Table

    SLOW_QUERY 提供了慢查询相关的一些信息。表里面的内容是通过解析 TiDB 慢日志文件的数据而来的，表中列名和慢日志中的字段名是一一对应的关系。更多操作可以参考慢查询日志文档。

    1.  mysql>desc SLOW_QUERY;
    2. +---------------+---------------------+------+-----+---------+-------+
    3. | Field         | Type                | Null | Key | Default | Extra |
    4. +---------------+---------------------+------+-----+---------+-------+
    5. | Time          | timestamp unsigned  | YES  |     | <null>  |       |
    6. | Txn_start_ts  | bigint(20) unsigned | YES  |     | <null>  |       |
    7. | User          | varchar(64)         | YES  |     | <null>  |       |
    8. | Host          | varchar(64)         | YES  |     | <null>  |       |
    9. | Conn_ID       | bigint(20) unsigned | YES  |     | <null>  |       |
    10. | Query_time    | double unsigned     | YES  |     | <null>  |       |
    11. | Process_time  | double unsigned     | YES  |     | <null>  |       |
    12. | Wait_time     | double unsigned     | YES  |     | <null>  |       |
    13. | Backoff_time  | double unsigned     | YES  |     | <null>  |       |
    14. | Request_count | bigint(20) unsigned | YES  |     | <null>  |       |
    15. | Total_keys    | bigint(20) unsigned | YES  |     | <null>  |       |
    16. | Process_keys  | bigint(20) unsigned | YES  |     | <null>  |       |
    17. | DB            | varchar(64)         | YES  |     | <null>  |       |
    18. | Index_ids     | varchar(100)        | YES  |     | <null>  |       |
    19. | Is_internal   | tinyint(1) unsigned | YES  |     | <null>  |       |
    20. | Digest        | varchar(64)         | YES  |     | <null>  |       |
    21. | Stats         | varchar(512)        | YES  |     | <null>  |       |
    22. | Cop_proc_avg  | double unsigned     | YES  |     | <null>  |       |
    23. | Cop_proc_p90  | double unsigned     | YES  |     | <null>  |       |
    24. | Cop_proc_max  | double unsigned     | YES  |     | <null>  |       |
    25. | Cop_proc_addr | varchar(64)         | YES  |     | <null>  |       |
    26. | Cop_wait_avg  | double unsigned     | YES  |     | <null>  |       |
    27. | Cop_wait_p90  | double unsigned     | YES  |     | <null>  |       |
    28. | Cop_wait_max  | double unsigned     | YES  |     | <null>  |       |
    29. | Cop_wait_addr | varchar(64)         | YES  |     | <null>  |       |
    30. | Mem_max       | bigint(20) unsigned | YES  |     | <null>  |       |
    31. | Query         | varchar(4096)       | YES  |     | <null>  |       |
    32. +---------------+---------------------+------+-----+---------+-------+

    STATISTICS Table

    STATISTICS 表提供了关于表索引的信息。

    1. mysql> desc statistics;
    2. +---------------|---------------------|------|------|---------|-------+
    3. | Field         | Type                | Null | Key  | Default | Extra |
    4. +---------------|---------------------|------|------|---------|-------+
    5. | TABLE_CATALOG | varchar(512)        | YES  |      | NULL    |       |
    6. | TABLE_SCHEMA  | varchar(64)         | YES  |      | NULL    |       |
    7. | TABLE_NAME    | varchar(64)         | YES  |      | NULL    |       |
    8. | NON_UNIQUE    | varchar(1)          | YES  |      | NULL    |       |
    9. | INDEX_SCHEMA  | varchar(64)         | YES  |      | NULL    |       |
    10. | INDEX_NAME    | varchar(64)         | YES  |      | NULL    |       |
    11. | SEQ_IN_INDEX  | bigint(2) UNSIGNED  | YES  |      | NULL    |       |
    12. | COLUMN_NAME   | varchar(21)         | YES  |      | NULL    |       |
    13. | COLLATION     | varchar(1)          | YES  |      | NULL    |       |
    14. | CARDINALITY   | bigint(21) UNSIGNED | YES  |      | NULL    |       |
    15. | SUB_PART      | bigint(3) UNSIGNED  | YES  |      | NULL    |       |
    16. | PACKED        | varchar(10)         | YES  |      | NULL    |       |
    17. | NULLABLE      | varchar(3)          | YES  |      | NULL    |       |
    18. | INDEX_TYPE    | varchar(16)         | YES  |      | NULL    |       |
    19. | COMMENT       | varchar(16)         | YES  |      | NULL    |       |
    20. | INDEX_COMMENT | varchar(1024)       | YES  |      | NULL    |       |
    21. +---------------|---------------------|------|------|---------|-------+

    下列语句是等价的：

    1. SELECT * FROM INFORMATION_SCHEMA.STATISTICS
    2.   WHERE table_name = 'tbl_name'
    3.   AND table_schema = 'db_name'
    5. SHOW INDEX
    6.   FROM tbl_name
    7.   FROM db_name

    TABLES Table

    TABLES 表提供了数据库里面关于表的信息。

    1. mysql> SELECT * FROM tables WHERE table_schema='mysql' AND table_name='user'\G
    2. *************************** 1. row ***************************
    3.   TABLE_CATALOG: def
    4.    TABLE_SCHEMA: mysql
    5.      TABLE_NAME: user
    6.      TABLE_TYPE: BASE TABLE
    7.          ENGINE: InnoDB
    8.         VERSION: 10
    9.      ROW_FORMAT: Compact
    10.      TABLE_ROWS: 0
    11.  AVG_ROW_LENGTH: 0
    12.     DATA_LENGTH: 0
    13. MAX_DATA_LENGTH: 0
    14.    INDEX_LENGTH: 0
    15.       DATA_FREE: 0
    16.  AUTO_INCREMENT: 0
    17.     CREATE_TIME: 2019-03-29 09:17:27
    18.     UPDATE_TIME: NULL
    19.      CHECK_TIME: NULL
    20. TABLE_COLLATION: utf8mb4_bin
    21.        CHECKSUM: NULL
    22.  CREATE_OPTIONS: 
    23.   TABLE_COMMENT: 
    24.   TIDB_TABLE_ID: 5
    25. 1 row in set (0.00 sec)

    以下操作是等价的：

    1. SELECT table_name FROM INFORMATION_SCHEMA.TABLES
    2.   WHERE table_schema = 'db_name'
    3.   [AND table_name LIKE 'wild']
    5. SHOW TABLES
    6.   FROM db_name
    7.   [LIKE 'wild']

    TABLE_CONSTRAINTS Table

    TABLE_CONSTRAINTS 表记录了表的约束信息。

    1. mysql> SELECT * FROM table_constraints WHERE constraint_type='UNIQUE'\G
    2. *************************** 1. row ***************************
    3. CONSTRAINT_CATALOG: def
    4.  CONSTRAINT_SCHEMA: mysql
    5.    CONSTRAINT_NAME: name
    6.       TABLE_SCHEMA: mysql
    7.         TABLE_NAME: help_topic
    8.    CONSTRAINT_TYPE: UNIQUE
    9. *************************** 2. row ***************************
    10. CONSTRAINT_CATALOG: def
    11.  CONSTRAINT_SCHEMA: mysql
    12.    CONSTRAINT_NAME: tbl
    13.       TABLE_SCHEMA: mysql
    14.         TABLE_NAME: stats_meta
    15.    CONSTRAINT_TYPE: UNIQUE
    16. *************************** 3. row ***************************
    17. CONSTRAINT_CATALOG: def
    18.  CONSTRAINT_SCHEMA: mysql
    19.    CONSTRAINT_NAME: tbl
    20.       TABLE_SCHEMA: mysql
    21.         TABLE_NAME: stats_histograms
    22.    CONSTRAINT_TYPE: UNIQUE
    23. *************************** 4. row ***************************
    24. CONSTRAINT_CATALOG: def
    25.  CONSTRAINT_SCHEMA: mysql
    26.    CONSTRAINT_NAME: tbl
    27.       TABLE_SCHEMA: mysql
    28.         TABLE_NAME: stats_buckets
    29.    CONSTRAINT_TYPE: UNIQUE
    30. *************************** 5. row ***************************
    31. CONSTRAINT_CATALOG: def
    32.  CONSTRAINT_SCHEMA: mysql
    33.    CONSTRAINT_NAME: delete_range_index
    34.       TABLE_SCHEMA: mysql
    35.         TABLE_NAME: gc_delete_range
    36.    CONSTRAINT_TYPE: UNIQUE
    37. *************************** 6. row ***************************
    38. CONSTRAINT_CATALOG: def
    39.  CONSTRAINT_SCHEMA: mysql
    40.    CONSTRAINT_NAME: delete_range_done_index
    41.       TABLE_SCHEMA: mysql
    42.         TABLE_NAME: gc_delete_range_done
    43.    CONSTRAINT_TYPE: UNIQUE
    44. 6 rows in set (0.00 sec)

    其中：

    • CONSTRAINT_TYPE 的取值可以是 UNIQUE，PRIMARY KEY，或者 FOREIGN KEY。
    • UNIQUE 和 PRIMARY KEY 信息与 SHOW INDEX 语句的执行结果类似。

    TIDB_HOT_REGIONS Table

    TIDB_HOT_REGIONS 表提供了关于热点 REGION 的相关信息。

    1. mysql> desc TIDB_HOT_REGIONS;
    2. +----------------+---------------------+------+-----+---------+-------+
    3. | Field          | Type                | Null | Key | Default | Extra |
    4. +----------------+---------------------+------+-----+---------+-------+
    5. | TABLE_ID       | bigint(21) unsigned | YES  |     | <null>  |       |
    6. | INDEX_ID       | bigint(21) unsigned | YES  |     | <null>  |       |
    7. | DB_NAME        | varchar(64)         | YES  |     | <null>  |       |
    8. | TABLE_NAME     | varchar(64)         | YES  |     | <null>  |       |
    9. | INDEX_NAME     | varchar(64)         | YES  |     | <null>  |       |
    10. | TYPE           | varchar(64)         | YES  |     | <null>  |       |
    11. | MAX_HOT_DEGREE | bigint(21) unsigned | YES  |     | <null>  |       |
    12. | REGION_COUNT   | bigint(21) unsigned | YES  |     | <null>  |       |
    13. | FLOW_BYTES     | bigint(21) unsigned | YES  |     | <null>  |       |
    14. +----------------+---------------------+------+-----+---------+-------+

    TIDB_INDEXES Table

    TIDB_INDEXES 记录了所有表中的 INDEX 信息。

    1. mysql>desc TIDB_INDEXES;
    2. +---------------+---------------------+------+-----+---------+-------+
    3. | Field         | Type                | Null | Key | Default | Extra |
    4. +---------------+---------------------+------+-----+---------+-------+
    5. | TABLE_SCHEMA  | varchar(64)         | YES  |     | <null>  |       |
    6. | TABLE_NAME    | varchar(64)         | YES  |     | <null>  |       |
    7. | NON_UNIQUE    | bigint(21) unsigned | YES  |     | <null>  |       |
    8. | KEY_NAME      | varchar(64)         | YES  |     | <null>  |       |
    9. | SEQ_IN_INDEX  | bigint(21) unsigned | YES  |     | <null>  |       |
    10. | COLUMN_NAME   | varchar(64)         | YES  |     | <null>  |       |
    11. | SUB_PART      | bigint(21) unsigned | YES  |     | <null>  |       |
    12. | INDEX_COMMENT | varchar(2048)       | YES  |     | <null>  |       |
    13. | INDEX_ID      | bigint(21) unsigned | YES  |     | <null>  |       |
    14. +---------------+---------------------+------+-----+---------+-------+

    TIKV_REGION_PEERS Table

    TIKV_REGION_PEERS 表提供了所有 REGION 的 peer 信息。

    1. mysql> desc TIKV_REGION_PEERS;
    2. +--------------+---------------------+------+-----+---------+-------+
    3. | Field        | Type                | Null | Key | Default | Extra |
    4. +--------------+---------------------+------+-----+---------+-------+
    5. | REGION_ID    | bigint(21) unsigned | YES  |     | <null>  |       |
    6. | PEER_ID      | bigint(21) unsigned | YES  |     | <null>  |       |
    7. | STORE_ID     | bigint(21) unsigned | YES  |     | <null>  |       |
    8. | IS_LEARNER   | tinyint(1) unsigned | YES  |     | <null>  |       |
    9. | IS_LEADER    | tinyint(1) unsigned | YES  |     | <null>  |       |
    10. | STATUS       | varchar(10)         | YES  |     | <null>  |       |
    11. | DOWN_SECONDS | bigint(21) unsigned | YES  |     | <null>  |       |
    12. +--------------+---------------------+------+-----+---------+-------+

    TIKV_REGION_STATUS Table

    TIKV_REGION_STATUS 表提供了所有 REGION 的状态信息。

    1. mysql> desc TIKV_REGION_STATUS;
    2. +------------------+---------------------+------+-----+---------+-------+
    3. | Field            | Type                | Null | Key | Default | Extra |
    4. +------------------+---------------------+------+-----+---------+-------+
    5. | REGION_ID        | bigint(21) unsigned | YES  |     | <null>  |       |
    6. | START_KEY        | text                | YES  |     | <null>  |       |
    7. | END_KEY          | text                | YES  |     | <null>  |       |
    8. | EPOCH_CONF_VER   | bigint(21) unsigned | YES  |     | <null>  |       |
    9. | EPOCH_VERSION    | bigint(21) unsigned | YES  |     | <null>  |       |
    10. | WRITTEN_BYTES    | bigint(21) unsigned | YES  |     | <null>  |       |
    11. | READ_BYTES       | bigint(21) unsigned | YES  |     | <null>  |       |
    12. | APPROXIMATE_SIZE | bigint(21) unsigned | YES  |     | <null>  |       |
    13. | APPROXIMATE_KEYS | bigint(21) unsigned | YES  |     | <null>  |       |
    14. +------------------+---------------------+------+-----+---------+-------+

    TIKV_STORE_STATUS Table

    TIKV_STORE_STATUS 表提供了所有 TiKV Store 的状态信息。

    1. mysql> desc TIKV_STORE_STATUS;
    2. +-------------------+---------------------+------+-----+---------+-------+
    3. | Field             | Type                | Null | Key | Default | Extra |
    4. +-------------------+---------------------+------+-----+---------+-------+
    5. | STORE_ID          | bigint(21) unsigned | YES  |     | <null>  |       |
    6. | ADDRESS           | varchar(64)         | YES  |     | <null>  |       |
    7. | STORE_STATE       | bigint(21) unsigned | YES  |     | <null>  |       |
    8. | STORE_STATE_NAME  | varchar(64)         | YES  |     | <null>  |       |
    9. | LABEL             | json unsigned       | YES  |     | <null>  |       |
    10. | VERSION           | varchar(64)         | YES  |     | <null>  |       |
    11. | CAPACITY          | varchar(64)         | YES  |     | <null>  |       |
    12. | AVAILABLE         | varchar(64)         | YES  |     | <null>  |       |
    13. | LEADER_COUNT      | bigint(21) unsigned | YES  |     | <null>  |       |
    14. | LEADER_WEIGHT     | bigint(21) unsigned | YES  |     | <null>  |       |
    15. | LEADER_SCORE      | bigint(21) unsigned | YES  |     | <null>  |       |
    16. | LEADER_SIZE       | bigint(21) unsigned | YES  |     | <null>  |       |
    17. | REGION_COUNT      | bigint(21) unsigned | YES  |     | <null>  |       |
    18. | REGION_WEIGHT     | bigint(21) unsigned | YES  |     | <null>  |       |
    19. | REGION_SCORE      | bigint(21) unsigned | YES  |     | <null>  |       |
    20. | REGION_SIZE       | bigint(21) unsigned | YES  |     | <null>  |       |
    21. | START_TS          | datetime unsigned   | YES  |     | <null>  |       |
    22. | LAST_HEARTBEAT_TS | datetime unsigned   | YES  |     | <null>  |       |
    23. | UPTIME            | varchar(64)         | YES  |     | <null>  |       |
    24. +-------------------+---------------------+------+-----+---------+-------+

    USER_PRIVILEGES Table

    USER_PRIVILEGES 表提供了关于全局权限的信息。该表的数据根据 mysql.user 系统表生成。

    1. mysql> desc USER_PRIVILEGES;
    2. +----------------|--------------|------|------|---------|-------+
    3. | Field          | Type         | Null | Key  | Default | Extra |
    4. +----------------|--------------|------|------|---------|-------+
    5. | GRANTEE        | varchar(81)  | YES  |      | NULL    |       |
    6. | TABLE_CATALOG  | varchar(512) | YES  |      | NULL    |       |
    7. | PRIVILEGE_TYPE | varchar(64)  | YES  |      | NULL    |       |
    8. | IS_GRANTABLE   | varchar(3)   | YES  |      | NULL    |       |
    9. +----------------|--------------|------|------|---------|-------+
    10. 4 rows in set (0.00 sec)

    VIEWS Table

    VIEWS 表提供了关于 SQL 视图的信息。

    1. mysql> create view test.v1 as select 1;
    2. Query OK, 0 rows affected (0.00 sec)
    3. mysql> select * from views\G
    4. *************************** 1. row ***************************
    5.        TABLE_CATALOG: def
    6.         TABLE_SCHEMA: test
    7.           TABLE_NAME: v1
    8.      VIEW_DEFINITION: select 1
    9.         CHECK_OPTION: CASCADED
    10.         IS_UPDATABLE: NO
    11.              DEFINER: root@127.0.0.1
    12.        SECURITY_TYPE: DEFINER
    13. CHARACTER_SET_CLIENT: utf8
    14. COLLATION_CONNECTION: utf8_general_ci
    15. 1 row in set (0.00 sec)

    不支持的 Information Schema 表

    TiDB 包含以下 INFORMATION_SCHEMA 表，但仅会返回空行：

    • COLUMN_PRIVILEGES
    • EVENTS
    • FILES
    • GLOBAL_STATUS
    • GLOBAL_VARIABLES
    • OPTIMIZER_TRACE
    • PARAMETERS
    • PARTITIONS
    • PLUGINS
    • PROFILING
    • REFERENTIAL_CONSTRAINTS
    • ROUTINES
    • SCHEMA_PRIVILEGES
    • SESSION_STATUS
    • TABLESPACES
    • TABLE_PRIVILEGES
    • TRIGGERS