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TIDB_HOT_REGIONS_HISTORY

The TIDB_HOT_REGIONS_HISTORY table provides information about history hot Regions that are periodically recorded locally by PD.

You can specify the record interval by configuring hot-regions-write-interval. The default value is 10 minutes. You can specify the period for reserving history information about hot Regions by configuring hot-regions-reserved-days. The default value is 7 days. See PD configuration file description for details.

By default, the record interval is 10 minutes, and the period for reserving history information about hot Regions is 7 days.

USE information_schema; DESC tidb_hot_regions_history;
+-------------+--------------+------+------+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------------+--------------+------+------+---------+-------+ | UPDATE_TIME | timestamp(6) | YES | | NULL | | | DB_NAME | varchar(64) | YES | | NULL | | | TABLE_NAME | varchar(64) | YES | | NULL | | | TABLE_ID | bigint(21) | YES | | NULL | | | INDEX_NAME | varchar(64) | YES | | NULL | | | INDEX_ID | bigint(21) | YES | | NULL | | | REGION_ID | bigint(21) | YES | | NULL | | | STORE_ID | bigint(21) | YES | | NULL | | | PEER_ID | bigint(21) | YES | | NULL | | | IS_LEARNER | tinyint(1) | NO | | 0 | | | IS_LEADER | tinyint(1) | NO | | 0 | | | TYPE | varchar(64) | YES | | NULL | | | HOT_DEGREE | bigint(21) | YES | | NULL | | | FLOW_BYTES | double | YES | | NULL | | | KEY_RATE | double | YES | | NULL | | | QUERY_RATE | double | YES | | NULL | | +-------------+--------------+------+------+---------+-------+ 16 rows in set (0.00 sec)

The fields in the TIDB_HOT_REGIONS_HISTORY table are described as follows:

  • UPDATE_TIME: The update time of the hot Region.
  • DB_NAME: The database name of the object in which the hot Region is located.
  • TABLE_ID: The ID of the table in which the hot Region is located.
  • TABLE_NAME: The name of the table in which the hot Region is located.
  • INDEX_NAME: The name of the index in which the hot Region is located.
  • INDEX_ID: The ID of the index in which the hot Region is located.
  • REGION_ID: The ID of the hot Region.
  • STORE_ID: The ID of the store in which the hot Region is located.
  • PEER_ID: The ID of the Peer corresponding to the hot Region.
  • IS_LEARNER: Whether the PEER is the LEARNER.
  • IS_LEADER: Whether the PEER is the LEADER.
  • TYPE: The type of the hot Region.
  • HOT_DEGREE: The hot degree of the hot Region.
  • FLOW_BYTES: The number of bytes written and read in the Region.
  • KEY_RATE: The number of keys written and read in the Region.
  • QUERY_RATE: The number of queries written and read in the Region.

Common user scenarios

  • Query hot Regions within a specific period of time. Replace update_time with your actual time.

    SELECT * FROM INFORMATION_SCHEMA.TIDB_HOT_REGIONS_HISTORY WHERE update_time >'2021-08-18 21:40:00' and update_time <'2021-09-19 00:00:00';
  • Query hot Regions in a table within a specific period of time. Replace update_time and table_name with your actual values.

    SELECT * FROM INFORMATION_SCHEMA.TIDB_HOT_REGIONS_HISTORY WHERE update_time >'2021-08-18 21:40:00' and update_time <'2021-09-19 00:00:00' and TABLE_NAME = 'table_name';
  • Query the distribution of hot Regions within a specific period of time. Replace update_time and table_name with your actual values.

    SELECT count(region_id) cnt, store_id FROM INFORMATION_SCHEMA.TIDB_HOT_REGIONS_HISTORY WHERE update_time >'2021-08-18 21:40:00' and update_time <'2021-09-19 00:00:00' and table_name = 'table_name' GROUP BY STORE_ID ORDER BY cnt DESC;
  • Query the distribution of hot Leader Regions within a specific period of time. Replace update_time and table_name with your actual values.

    SELECT count(region_id) cnt, store_id FROM INFORMATION_SCHEMA.TIDB_HOT_REGIONS_HISTORY WHERE update_time >'2021-08-18 21:40:00' and update_time <'2021-09-19 00:00:00' and table_name = 'table_name' and is_leader=1 GROUP BY STORE_ID ORDER BY cnt DESC;
  • Query the distribution of hot Index Regions within a specific period of time. Replace update_time and table_name with your actual values.

    SELECT count(region_id) cnt, index_name, store_id FROM INFORMATION_SCHEMA.TIDB_HOT_REGIONS_HISTORY WHERE update_time >'2021-08-18 21:40:00' and update_time <'2021-09-19 00:00:00' and table_name = 'table_name' group by index_name, store_id order by index_name,cnt desc;
  • Query the distribution of hot Index Leader Regions within a specific period of time. Replace update_time and table_name with your actual values.

    SELECT count(region_id) cnt, index_name, store_id FROM INFORMATION_SCHEMA.TIDB_HOT_REGIONS_HISTORY WHERE update_time >'2021-08-18 21:40:00' and update_time <'2022-09-19 00:00:00' and table_name = 'table_name' and is_leader=1 group by index_name, store_id order by index_name,cnt desc;

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