pg_stats_ext_exprs
A system view containing information about all expressions included in extended statistics objects
This entry relates to a PostgreSQL feature which is part of PostgreSQL 14, due to be released in late 2021.
pg_stats_ext_exprs is a system catalog view storing information about extended statistics objects which include expressions.
pg_stats_ext_exprs was added in PostgreSQL 14.
Definition by PostgreSQL version
pg_stats_ext_exprs (PostgreSQL 15)
View "pg_catalog.pg_stats_ext_exprs"
Column | Type | Collation | Nullable | Default
------------------------+----------+-----------+----------+---------
schemaname | name | | |
tablename | name | | |
statistics_schemaname | name | | |
statistics_name | name | | |
statistics_owner | name | | |
expr | text | | |
null_frac | real | | |
avg_width | integer | | |
n_distinct | real | | |
most_common_vals | anyarray | | |
most_common_freqs | real[] | | |
histogram_bounds | anyarray | | |
correlation | real | | |
most_common_elems | anyarray | | |
most_common_elem_freqs | real[] | | |
elem_count_histogram | real[] | | |
Documentation: pg_stats_ext_exprs
pg_stats_ext_exprs (PostgreSQL 14)
View "pg_catalog.pg_stats_ext_exprs"
Column | Type | Collation | Nullable | Default
------------------------+----------+-----------+----------+---------
schemaname | name | | |
tablename | name | | |
statistics_schemaname | name | | |
statistics_name | name | | |
statistics_owner | name | | |
expr | text | | |
null_frac | real | | |
avg_width | integer | | |
n_distinct | real | | |
most_common_vals | anyarray | | |
most_common_freqs | real[] | | |
histogram_bounds | anyarray | | |
correlation | real | | |
most_common_elems | anyarray | | |
most_common_elem_freqs | real[] | | |
elem_count_histogram | real[] | | |
Documentation: pg_stats_ext_exprs
Change history
- PostgreSQL 14
- added (commit a4d75c86)
Examples
Basic usage example for pg_stats_ext_exprs:
postgres=# CREATE TABLE foo (id int); CREATE TABLE postgres=# INSERT INTO foo values(generate_series(1,10000)); INSERT 0 10000 postgres=# CREATE STATISTICS s ON mod(id,5) FROM foo; CREATE STATISTICS postgres=# SELECT * FROM pg_stats_ext_exprs; -[ RECORD 1 ]----------+---------------------- schemaname | public tablename | foo statistics_schemaname | public statistics_name | s statistics_owner | postgres expr | mod(id, 5) null_frac | 0 avg_width | 4 n_distinct | 5 most_common_vals | {0,1,2,3,4} most_common_freqs | {0.2,0.2,0.2,0.2,0.2} histogram_bounds | correlation | 0.19999996 most_common_elems | most_common_elem_freqs | elem_count_histogram | postgres=# ANALYZE foo; ANALYZE
References
- PostgreSQL 14 documentation: pg_stats_ext_exprs