PG_PARTITION

PG_PARTITION records all partitioned tables, table partitions, and index partitions in the database. Partitioned index information is not stored in the system catalog PG_PARTITION. The partitioned table does not have actual physical files. Therefore, pg_partition does not record information such as relfilenode, relpages, reltuples, reltoastrelid, and reltoastidxid.

**Table 1** PG_PARTITION columns
Name	Type	Description
oid	oid	Row identifier (hidden attribute, which must be specified).
relname	name	Names of the partitioned tables, table partitions, TOAST tables on table partitions, and index partitions.
parttype	"char"	Object type. r: partitioned table p: table partition s: table subpartition x: index partition
parentid	oid	OID of the partitioned table in PG_CLASS when the object is a partitioned table or a partition. OID of the level-1 partition in PG_PARTITION when the object is a level-2 partition. OID of the partitioned index when the object is an index partition.
rangenum	integer	Reserved column.
intervalnum	integer	Reserved column.
partstrategy	"char"	Partition policy of the partitioned table r: range partition v: numeric partition i: interval partition l: list partition h: hash partition n: invalid partition
relfilenode	oid	Physical storage locations of the table partition, index partition, and TOAST table on the table partition
reltablespace	oid	OID of the tablespace containing the table partition, index partition, and TOAST table on the table partition
relpages	double precision	Statistics: numbers of data pages of the table partition and index partition
reltuples	double precision	Statistics: numbers of tuples of the table partition and index partition
relallvisible	integer	Statistics: number of visible data pages of the table partition and index partition
reltoastrelid	oid	OID of the TOAST table corresponding to the table partition
reltoastidxid	oid	OID of the TOAST table index corresponding to the table partition
indextblid	oid	OID of the table partition corresponding to the index partition
indisusable	boolean	Whether the index partition is available
relfrozenxid	xid32	Frozen transaction ID To ensure forward compatibility, this column is reserved. The relfrozenxid64 column is added to record the information.
intspnum	integer	Number of tablespaces that the interval partition belongs to
partkey	int2vector	Column number of the partition key
intervaltablespace	oidvector	Tablespace that the interval partition belongs to. Interval partitions fall in the tablespaces in the round-robin manner.
interval	text[]	Interval value of the interval partition
boundaries	text[]	Upper boundary of the range partition and interval partition
transit	text[]	Transit of the interval partition
reloptions	text[]	Storage property of a partition used for collecting online scale-out information. Same as pg_class.reloptions, it is expressed in a string in the format of keyword=value.
relfrozenxid64	xid	Frozen transaction ID
relminmxid	xid	Frozen multi-transaction ID
partitionno	integer	Used for maintaining the partition map of a partitioned table. If the object is a partition, this field indicates the partition ID, which starts from 1 in ascending order. If the object is a partitioned table, this field indicates the maximum partition ID and a negative value is used for special meaning. The value increases with the DDL syntax of some partitions. If the object is of other types, this field is null and has no meaning. partitionno is a permanent auto-increment column, which can be reset or reclaimed by using the syntax ALTER TABLE t_name RESET PARTITION or VACUUM FULL.
subpartitionno	integer	Used for maintaining the map of level-2 partitions in a partitioned table. If the object is a level-2 partition, this field indicates the level-2 partition ID, which starts from 1 in ascending order. If the object is a level-1 partition in a level-2 partitioned table, this field indicates the maximum level-2 partition ID and a negative value is used for special meaning. This value increases with the DDL syntax of some partitions. If the object is of other types, this field is null and has no meaning. subpartitionno is a permanent auto-increment column, which can be reset or reclaimed by using the syntax ALTER TABLE t_name RESET PARTITION or VACUUM FULL.