How can I tell if PostgreSQL's Autovacuum is running on UNIX? - postgresql

Question

How can one tell if the autovacuum daemon in Postgres 9.x is running and maintaining the database cluster?

Answer 1

PostgreSQL 9.3
Determine if Autovacuum is Running
This is specific to Postgres 9.3 on UNIX.
For Windows, see this question.
Query Postgres System Table
SELECT
schemaname, relname,
last_vacuum, last_autovacuum,
vacuum_count, autovacuum_count -- not available on 9.0 and earlier
FROM pg_stat_user_tables;
Grep System Process Status
$ ps -axww | grep autovacuum
24352 ?? Ss 1:05.33 postgres: autovacuum launcher process (postgres)
Grep Postgres Log
# grep autovacuum /var/log/postgresql
LOG: autovacuum launcher started
LOG: autovacuum launcher shutting down
If you want to know more about the autovacuum activity, set log_min_messages to DEBUG1..DEBUG5. The SQL command VACUUM VERBOSE will output information at log level INFO.
Regarding the Autovacuum Daemon, the Posgres docs state:
In the default configuration, autovacuuming is enabled and the related configuration parameters are appropriately set.
See Also:
http://www.postgresql.org/docs/current/static/routine-vacuuming.html
http://www.postgresql.org/docs/current/static/runtime-config-autovacuum.html

Answer 2

I'm using:
select count(*) from pg_stat_activity where query like 'autovacuum:%';
in collectd to know how many autovacuum are running concurrently.
You may need to create a security function like this:
CREATE OR REPLACE FUNCTION public.pg_autovacuum_count() RETURNS bigint
AS 'select count(*) from pg_stat_activity where query like ''autovacuum:%'';'
LANGUAGE SQL
STABLE
SECURITY DEFINER;
and call that from collectd.
In earlier Postgres, "query" was "current_query" so change it according to what works.

Answer 3

You can also run pg_activity to see the currently running queries on your database. I generally leave a terminal open with this running most of the time anyway as it's very useful.

Answer 4

set log_autovacuum_min_duration to the time length that you desire and the autovacuum execution exceeds the time length will be logged.