51.26. pg_index
The catalog
pg_index
contains part of the information
about indexes. The rest is mostly in
pg_class
.
Table 51.26.
pg_index
Columns
| Name | Type | References | Description |
|---|---|---|---|
indexrelid
|
oid
|
|
The OID of the
pg_class
entry for this index
|
indrelid
|
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
|
bool
|
If true, this is a unique index | |
indisprimary
|
bool
|
If true, this index represents the primary key of the table
(
indisunique
should always be true when this is true)
|
|
indisexclusion
|
bool
|
If true, this index supports an exclusion constraint | |
indimmediate
|
bool
|
If true, the uniqueness check is enforced immediately on
insertion
(irrelevant if
indisunique
is not true)
|
|
indisclustered
|
bool
|
If true, the table was last clustered on this index | |
indisvalid
|
bool
|
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. If it is unique, the uniqueness property is not
guaranteed true either.
|
|
indcheckxmin
|
bool
|
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
|
bool
|
If true, the index is currently ready for inserts. False means the
index must be ignored by
INSERT
/
UPDATE
operations.
|
|
indislive
|
bool
|
If false, the index is in process of being dropped, and should be ignored for all purposes (including HOT-safety decisions) | |
indisreplident
|
bool
|
If true this index has been chosen as
"
replica identity
"
using
ALTER TABLE ... REPLICA IDENTITY USING INDEX
...
|
|
indkey
|
int2vector
|
|
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, or zero if the column is not of a collatable data type. |
indclass
|
oidvector
|
|
For each column in the index key, this contains the OID of
the operator class to use. See
pg_opclass
for details.
|
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
|
pg_node_tree
|
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
|
pg_node_tree
|
Expression tree (in
nodeToString()
representation) for partial index predicate. Null if not a
partial index.
|