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. 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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https://mariadb.com/kb/en/information-schema-partitions-table/