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