PG_STAT_ALL_INDEXES

PG_STAT_ALL_INDEXES is used to query statistics about accesses to a specific index by querying each index row in the current database.

Indexes can be used via either simple index scans or bitmap index scans. In a bitmap scan the output of several indexes can be combined via AND or OR rules, so it is difficult to associate individual heap row fetches with specific indexes when a bitmap scan is used. Therefore, each bitmap scan increments the pg_stat_all_indexes.idx_tup_read count(s) for the index(es) it uses, and it increments the pg_stat_all_tables.idx_tup_fetch count for the table, but it does not affect pg_stat_all_indexes.idx_tup_fetch.

**Table 1** PG_STAT_ALL_INDEXES columns
Name	Type	Description
relid	oid	OID of the table that the index is created for.
indexrelid	oid	OID of the index.
schemaname	name	Name of the schema that the index is in.
relname	name	Name of the table for the index.
indexrelname	name	Index name.
idx_scan	bigint	Number of index scans initiated on the index.
idx_tup_read	bigint	Number of index entries returned by scans on the index.
idx_tup_fetch	bigint	Number of live rows fetched in the original table by a simple index scan that uses the index.