Information Schema PARTITIONS Table
The Information Schema PARTITIONS contains information about table partitions, with each record corresponding to a single partition or subpartition of a partitioned table. Each non-partitioned table also has a record in the PARTITIONS table, but most of the values are NULL.
It contains the following columns:
| Column | Description |
|---|---|
TABLE_CATALOG | Always def. |
TABLE_SCHEMA | Database name. |
TABLE_NAME | Table name containing the partition. |
PARTITION_NAME | Partition name. |
SUBPARTITION_NAME | Subpartition name, or NULL if not a subpartition. |
PARTITION_ORDINAL_POSITION | Order of the partition starting from 1. |
SUBPARTITION_ORDINAL_POSITION | Order of the subpartition starting from 1. |
PARTITION_METHOD | The partitioning type; one of RANGE, LIST, HASH, LINEAR HASH, KEY or LINEAR KEY. |
SUBPARTITION_METHOD | Subpartition type; one of HASH, LINEAR HASH, KEY or LINEAR KEY, or NULL if not a subpartition. |
PARTITION_EXPRESSION | Expression used to create the partition by the CREATE TABLE or ALTER TABLE statement. |
SUBPARTITION_EXPRESSION | Expression used to create the subpartition by the CREATE TABLE or ALTER TABLE statement, or NULL if not a subpartition. |
PARTITION_DESCRIPTION | For a RANGE partition, contains either MAXINTEGER or an integer, as set in the VALUES LESS THAN clause. For a LIST partition, contains a comma-separated list of integers, as set in the VALUES IN. For a SYSTEM_TIME INTERVAL partition, shows a defined upper boundary timestamp for historical values (the last history partition can contain values above the upper boundary). NULL if another type of partition. |
TABLE_ROWS | Number of rows in the table (may be an estimate for some storage engines). |
AVG_ROW_LENGTH | Average row length, that is DATA_LENGTH divided by TABLE_ROWS |
DATA_LENGTH | Total number of bytes stored in all rows of the partition. |
MAX_DATA_LENGTH | Maximum bytes that could be stored in the partition. |
INDEX_LENGTH | Size in bytes of the partition index file. |
DATA_FREE | Unused bytes allocated to the partition. |
CREATE_TIME | Time the partition was created |
UPDATE_TIME | Time the partition was last modified. |
CHECK_TIME | Time the partition was last checked, or NULL for storage engines that don't record this information. |
CHECKSUM | Checksum value, or NULL if none. |
PARTITION_COMMENT | Partition comment, truncated to 80 characters, or an empty string if no comment. |
NODEGROUP | Node group, only used for MySQL Cluster, defaults to 0. |
TABLESPACE_NAME | Always default. |
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