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

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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