pg_stat_get_backend_idset()

A function providing a sequential IDs for each backend

pg_stat_get_backend_idset() is a system function which generates a list of sequential IDs for each current backend, which can then be provided to a of functions, each of which returns a specifc items of information about each backend. These functions underly the pg_stat_activity view, but can be used to extract a subset of information provided by that view.

pg_stat_get_backend_idset() was added in PostgreSQL 7.2.

Usage

pg_stat_get_backend_idset () → setof integer

The provided number ranges from 1 to the number of currently active backends.

Change history

Examples

Basic usage example for pg_stat_get_backend_idset():

postgres=# SELECT * FROM pg_stat_get_backend_idset();
 pg_stat_get_backend_idset 
---------------------------
                         1
                         2
                         3
                         4
                         5
                         6
                         7
                         8
                         9
                        10
                        11
                        12
                        13
                        14
                        15
                        16
                        17
                        18
(18 rows)

By itself this information is of little use; normally this query will be combined with one or more of the per-backend statistics functions:

postgres=# SELECT pg_stat_get_backend_pid(s.id) AS pid
             FROM (SELECT pg_stat_get_backend_idset() AS id) AS s;
   pid   
---------
 1451980
 1451982
 1455628
 1764534
 1468447
 1468445
 1468005
 1468202
 1451978
 1451977
 1451979
(11 rows)

Categories

System function

See also

pg_stat_get_backend_activity(), pg_stat_get_backend_activity_start(), pg_stat_get_backend_client_addr(), pg_stat_get_backend_client_port(), pg_stat_get_backend_dbid(), pg_stat_get_backend_pid(), pg_stat_get_backend_start(), pg_stat_get_backend_userid(), pg_stat_get_backend_wait_event(), pg_stat_get_backend_wait_event_type(), pg_stat_get_backend_xact_start()