System Catalogs Definitions - pg_index - 《Greenplum Database v6.23 Documentation》

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

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.

Parent topic: System Catalogs Definitions