partitions
partitions provides information about table partitions.
The following fields are provided in partitions:
| Field | Description |
|---|---|
| TABLE_CATALOG | The name of the catalog to which the table belongs. This value is always def. |
| TABLE_SCHEMA | The name of the database to which the table belongs. |
| TABLE_NAME | The name of the table containing the partition. |
| PARTITION_NAME | The name of the partition. |
| SUBPARTITION_NAME | If the PARTITIONS table row represents a subpartition, the name of subpartition; otherwise NULL.For NDB: This value is always NULL. |
| PARTITION_ORDINAL_POSITION | All partitions are indexed in the same order as they are defined, with 1 being the number assigned to the first partition. The indexing can change as partitions are added, dropped, and reorganized; the number shown is this column reflects the current order, taking into account any indexing changes. |
| PARTITION_METHOD | Valid values: RANGE, LIST, HASH, LINEAR HASH, KEY, or LINEAR KEY. |
| SUBPARTITION_METHOD | Valid values: HASH, LINEAR HASH, KEY, or LINEAR KEY |
| PARTITION_EXPRESSION | The expression for the partitioning function used in the CREATE TABLE or ALTER TABLE statement that created the table's current partitioning scheme. |
| SUBPARTITION_EXPRESSION | This works in the same fashion for the subpartitioning expression that defines the subpartitioning for a table as PARTITION_EXPRESSION does for the partitioning expression used to define a table's partitioning. If the table has no subpartitions, this column is NULL. |
| PARTITION_DESCRIPTION | This column is used for RANGE and LIST partitions. For a RANGE partition, it contains the value set in the partition's VALUES LESS THAN clause, which can be either an integer or MAXVALUE. For a LIST partition, this column contains the values defined in the partition's VALUES IN clause, which is a list of comma-separated integer values.For partitions whose PARTITION_METHOD is other than RANGE or LIST, this column is always NULL. |
| TABLE_ROWS | The number of table rows in the partition. |
| AVG_ROW_LENGTH | The average length of the rows stored in this partition or subpartition, in bytes. This is the same as DATA_LENGTH divided by TABLE_ROWS. |
| DATA_LENGTH | The total length of all rows stored in this partition or subpartition, in bytes; that is, the total number of bytes stored in the partition or subpartition. |
| MAX_DATA_LENGTH | The maximum number of bytes that can be stored in this partition or subpartition. |
| INDEX_LENGTH | The length of the index file for this partition or subpartition, in bytes. |
| DATA_FREE | The number of bytes allocated to the partition or subpartition but not used. |
| CREATE_TIME | The time that the partition or subpartition was created. |
| UPDATE_TIME | The time that the partition or subpartition was last modified. |
| CHECK_TIME | The last time that the table to which this partition or subpartition belongs was checked. |
| CHECKSUM | The checksum value, if any; otherwise NULL. |
| PARTITION_COMMENT | The text of the comment, if the partition has one. If not, this value is empty. |
| NODEGROUP | This is the nodegroup to which the partition belongs. |
| TABLESPACE_NAME | The name of the tablespace to which the partition belongs. |