pg_index

The pg_index system catalog table contains part of the information about indexes. The rest is mostly in pg_class.

Column Type References Description

Column	Type	References	Description
indexrelid	oid	pg_class.oid	The OID of the `pg_class` entry for this index
indrelid	oid	pg_class.oid	The OID of the `pg_class` entry for the table this index is for
indnatts	int2	—	The number of columns in the index (duplicates `pg_class.relnatts`)
indisunique	boolean	—	If `true`, this is a unique index
indisprimary	boolean	—	If `true`, this index represents the primary key of the table. `indisunique` should always be `true` when this is `true`
indisexclusion	boolean	—	If `true`, this index supports an exclusion constraint
indimmediate	boolean	—	If `true`, the uniqueness check is enforced immediately on insertion (irrelevant if `indisunique` is not `true`)
indisclustered	boolean	—	If `true`, the table was last clustered on this index via the `CLUSTER` command
indisvalid	boolean	—	If `true`, the index is currently valid for queries. `false` means the index is possibly incomplete: it must still be modified by `INSERT`/`UPDATE` operations, but it cannot safely be used for queries
indcheckxmin	boolean	—	If `true`, queries must not use the index until the `xmin` of this `pg_index` row is below their `TransactionXmin` event horizon, because the table may contain broken HOT chains with incompatible rows that they can see
indisready	boolean	—	If `true`, the index is currently ready for inserts. `false` means the index must be ignored by `INSERT`/`UPDATE` operations
indislive	boolean	—	If `false`, the index is in process of being dropped, and should be ignored for all purposes
indisreplident	boolean	—	If `true` this index has been chosen as "replica identity" using `ALTER TABLE … REPLICA IDENTITY USING INDEX …`
indkey	int2vector	pg_attribute.attnum	This is an array of `indnatts` values that indicate which table columns this index indexes. For example, a value of `1 3` would mean that the first and the third table columns make up the index key. A zero in this array indicates that the corresponding index attribute is an expression over the table columns, rather than a simple column reference
indcollation	oidvector	—	For each column in the index key, this contains the OID of the collation to use for the index
indclass	oidvector	pg_opclass.oid	For each column in the index key this contains the OID of the operator class to use
indoption	int2vector	—	This is an array of `indnatts` values that store per-column flag bits. The meaning of the bits is defined by the index’s access method
indexprs	text	—	Expression trees (in `nodeToString()` representation) for index attributes that are not simple column references. This is a list with one element for each zero entry in `indkey`. `NULL` if all index attributes are simple references
indpred	text	—	Expression tree (in `nodeToString()` representation) for partial index predicate. `NULL` if not a partial index

indexrelid

oid

pg_class.oid

The OID of the pg_class entry for this index

indrelid

oid

pg_class.oid

The OID of the pg_class entry for the table this index is for

indnatts

int2

—

The number of columns in the index (duplicates pg_class.relnatts)

indisunique

boolean

—

If true, this is a unique index

indisprimary

boolean

—

If true, this index represents the primary key of the table. indisunique should always be true when this is true

indisexclusion

boolean

—

If true, this index supports an exclusion constraint

indimmediate

boolean

—

If true, the uniqueness check is enforced immediately on insertion (irrelevant if indisunique is not true)

indisclustered

boolean

—

If true, the table was last clustered on this index via the CLUSTER command

indisvalid

boolean

—

If true, the index is currently valid for queries. false means the index is possibly incomplete: it must still be modified by INSERT/UPDATE operations, but it cannot safely be used for queries

indcheckxmin

boolean

—

If true, queries must not use the index until the xmin of this pg_index row is below their TransactionXmin event horizon, because the table may contain broken HOT chains with incompatible rows that they can see

indisready

boolean

—

If true, the index is currently ready for inserts. false means the index must be ignored by INSERT/UPDATE operations

indislive

boolean

—

If false, the index is in process of being dropped, and should be ignored for all purposes

indisreplident

boolean

—

If true this index has been chosen as "replica identity" using ALTER TABLE … REPLICA IDENTITY USING INDEX …

indkey

int2vector

pg_attribute.attnum

This is an array of indnatts values that indicate which table columns this index indexes. For example, a value of 1 3 would mean that the first and the third table columns make up the index key. A zero in this array indicates that the corresponding index attribute is an expression over the table columns, rather than a simple column reference

indcollation

oidvector

—

For each column in the index key, this contains the OID of the collation to use for the index

indclass

oidvector

pg_opclass.oid

For each column in the index key this contains the OID of the operator class to use

indoption

int2vector

—

This is an array of indnatts values that store per-column flag bits. The meaning of the bits is defined by the index’s access method

indexprs

text

—

Expression trees (in nodeToString() representation) for index attributes that are not simple column references. This is a list with one element for each zero entry in indkey. NULL if all index attributes are simple references

indpred

text

—

Expression tree (in nodeToString() representation) for partial index predicate. NULL if not a partial index

pg_foreign_table

pg_inherits