TIFLASH_SEGMENTS

TIFLASH_SEGMENTS - 图1

Warning

Do not use this table in production environments, as the fields of the table are unstable, and subject to change in new releases of TiDB, without prior notice.

TIFLASH_SEGMENTS - 图2

Note

This table is not available on TiDB Serverless clusters.

The TIFLASH_SEGMENTS table provides statistical information about data tables in TiFlash.

  1. USE information_schema;
  2. DESC tiflash_segments;
  1. +-------------------------------+-------------+------+------+---------+-------+
  2. | Field                         | Type        | Null | Key  | Default | Extra |
  3. +-------------------------------+-------------+------+------+---------+-------+
  4. | DATABASE                      | varchar(64) | YES  |      | NULL    |       |
  5. | TABLE                         | varchar(64) | YES  |      | NULL    |       |
  6. | TIDB_DATABASE                 | varchar(64) | YES  |      | NULL    |       |
  7. | TIDB_TABLE                    | varchar(64) | YES  |      | NULL    |       |
  8. | TABLE_ID                      | bigint(64)  | YES  |      | NULL    |       |
  9. | IS_TOMBSTONE                  | bigint(64)  | YES  |      | NULL    |       |
  10. | SEGMENT_ID                    | bigint(64)  | YES  |      | NULL    |       |
  11. | RANGE                         | varchar(64) | YES  |      | NULL    |       |
  12. | EPOCH                         | bigint(64)  | YES  |      | NULL    |       |
  13. | ROWS                          | bigint(64)  | YES  |      | NULL    |       |
  14. | SIZE                          | bigint(64)  | YES  |      | NULL    |       |
  15. | DELTA_RATE                    | double      | YES  |      | NULL    |       |
  16. | DELTA_MEMTABLE_ROWS           | bigint(64)  | YES  |      | NULL    |       |
  17. | DELTA_MEMTABLE_SIZE           | bigint(64)  | YES  |      | NULL    |       |
  18. | DELTA_MEMTABLE_COLUMN_FILES   | bigint(64)  | YES  |      | NULL    |       |
  19. | DELTA_MEMTABLE_DELETE_RANGES  | bigint(64)  | YES  |      | NULL    |       |
  20. | DELTA_PERSISTED_PAGE_ID       | bigint(64)  | YES  |      | NULL    |       |
  21. | DELTA_PERSISTED_ROWS          | bigint(64)  | YES  |      | NULL    |       |
  22. | DELTA_PERSISTED_SIZE          | bigint(64)  | YES  |      | NULL    |       |
  23. | DELTA_PERSISTED_COLUMN_FILES  | bigint(64)  | YES  |      | NULL    |       |
  24. | DELTA_PERSISTED_DELETE_RANGES | bigint(64)  | YES  |      | NULL    |       |
  25. | DELTA_CACHE_SIZE              | bigint(64)  | YES  |      | NULL    |       |
  26. | DELTA_INDEX_SIZE              | bigint(64)  | YES  |      | NULL    |       |
  27. | STABLE_PAGE_ID                | bigint(64)  | YES  |      | NULL    |       |
  28. | STABLE_ROWS                   | bigint(64)  | YES  |      | NULL    |       |
  29. | STABLE_SIZE                   | bigint(64)  | YES  |      | NULL    |       |
  30. | STABLE_DMFILES                | bigint(64)  | YES  |      | NULL    |       |
  31. | STABLE_DMFILES_ID_0           | bigint(64)  | YES  |      | NULL    |       |
  32. | STABLE_DMFILES_ROWS           | bigint(64)  | YES  |      | NULL    |       |
  33. | STABLE_DMFILES_SIZE           | bigint(64)  | YES  |      | NULL    |       |
  34. | STABLE_DMFILES_SIZE_ON_DISK   | bigint(64)  | YES  |      | NULL    |       |
  35. | STABLE_DMFILES_PACKS          | bigint(64)  | YES  |      | NULL    |       |
  36. | TIFLASH_INSTANCE              | varchar(64) | YES  |      | NULL    |       |
  37. +-------------------------------+-------------+------+------+---------+-------+
  38. 33 rows in set (0.00 sec)

Fields in the TIFLASH_SEGMENTS table are described as follows:

  • DATABASE: Database name in TiFlash. The segment belongs to a table in this database.
  • TABLE: Table name in TiFlash. The segment belongs to this table.
  • TIDB_DATABASE: Database name in TiDB. The segment belongs to a table in this database.
  • TIDB_TABLE: Table name in TiDB. The segment belongs to this table.
  • TABLE_ID: The internal ID of the table to which the segment belongs. This ID is unique within a TiDB cluster.
  • IS_TOMBSTONE: Indicates whether the table the segment belongs to can be recycled. 1 indicates that the table can be recycled. 0 indicates that the table is in a normal state.
  • SEGMENT_ID: Segment ID, which is unique within a table.
  • RANGE: The range of data that the segment contains.
  • EPOCH: The updated version of the segment. The version number of each segment increases monotonically.
  • ROWS: The total number of rows in the segment.
  • SIZE: The total size of the segment data (in bytes).
  • DELTA_RATE: The ratio of the total number of rows in the Delta layer to that in the segment.
  • DELTA_MEMTABLE_ROWS: The total number of cached rows in the Delta layer.
  • DELTA_MEMTABLE_SIZE: The total size of the data cached in the Delta layer (in bytes).
  • DELTA_MEMTABLE_COLUMN_FILES: The number of Column Files cached in the Delta layer.
  • DELTA_MEMTABLE_DELETE_RANGES: The number of Delete Ranges cached in the Delta layer.
  • DELTA_PERSISTED_PAGE_ID: The ID of the data stored on a disk in the Delta layer.
  • DELTA_PERSISTED_ROWS: The total number of rows of persisted data in the Delta layer.
  • DELTA_PERSISTED_SIZE: The total size of the persisted data in the Delta layer (in bytes).
  • DELTA_PERSISTED_COLUMN_FILES: The number of persisted Column Files in the Delta layer.
  • DELTA_PERSISTED_DELETE_RANGES: The number of persisted Delete Ranges in the Delta layer.
  • DELTA_CACHE_SIZE: The size of the cache in the Delta layer (in bytes).
  • DELTA_INDEX_SIZE: The size of the indexes in the Delta layer (in bytes).
  • STABLE_PAGE_ID: The disk storage ID of the data in the Stable layer.
  • STABLE_ROWS: The total number of rows in the Stable layer.
  • STABLE_SIZE: The total size of the data in the Stable layer (in bytes).
  • STABLE_DMFILES: The number of DMFiles in the Stable layer.
  • STABLE_DMFILES_ID_0: The disk storage ID of the first DMFile in the Stable layer.
  • STABLE_DMFILES_ROWS: The total number of rows in the DMFile in the Stable layer.
  • STABLE_DMFILES_SIZE: The total size of the data in the DMFile in the Stable layer (in bytes).
  • STABLE_DMFILES_SIZE_ON_DISK: The disk space occupied by the DMFile in the Stable layer (in bytes).
  • STABLE_DMFILES_PACKS: The number of Packs in the DMFile in the Stable layer.
  • TIFLASH_INSTANCE: The address of the TiFlash instance.