PG_INDEX

PG_INDEX records part of index information. The rest is mostly recorded in PG_CLASS.

Table 1 PG_INDEX columns

Name

Type

Description

indexrelid

oid

OID of the PG_CLASS entry for the index

indrelid

oid

OID of the PG_CLASS entry for the table that uses the index

indnatts

smallint

Number of columns in the index

indisunique

Boolean

This index is a unique index if the value is true.

This index is not a unique index if the value is false.

indisprimary

Boolean

Primary key of the table if the value is true. indisunique should always be true when the value of this column is true.

This index is not the primary key of the table if the value is false.

indisexclusion

Boolean

Whether the index supports exclusion constraints

This index does not support exclusion constraints if the value is false.

indimmediate

Boolean

Whether a uniqueness check is performed upon data insertion

A uniqueness check is not performed upon data insertion if the value is false.

indisclustered

Boolean

Whether the table was last clustered on the index

The table is not clustered on this index if the value is false.

indisusable

Boolean

Whether the index supports INSERT/SELECT

This index does not support INSERT/SELECT if the value is false.

indisvalid

Boolean

Whether the index is valid for queries. If this column is false, the index is possibly incomplete and must still be modified by INSERT/UPDATE operations, but it cannot safely be used for queries. If it is a unique index, the uniqueness property is also not true.

indcheckxmin

Boolean

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

If the value is false, queries can use indexes.

indisready

Boolean

The index is available for inserted data if the value is true. Otherwise, this index is ignored when data is inserted or modified.

indkey

int2vector

This is an array of indnatts values indicating that this index creates table columns. For example, a value of 1 3 indicates that the first and the third columns make up the index key. The value 0 in this array indicates that the corresponding index attribute is an expression over the table columns, rather than a simple column reference.

indcollation

oidvector

ID of each column used by the index

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

Array of 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. It is a list with one element for each zero entry in INDKEY. The value is NULL if all index attributes are simple references.

indpred

pg_node_tree

Expression tree (in nodeToString() representation) for partial index predicate. If the index is not a partial index, this column is an empty string.

indisreplident

Boolean

If the value is true, the column of this index becomes the decoded column of logical decoding.

If the value is false, the column of this index is not the decoded column of logical decoding.

indnkeyatts

smallint

Total number of columns in the index. The columns that exceed the value of indnatts are not involved in the index query.

Feedback
编组 3备份
    openGauss 2024-04-12 00:46:38
    cancel