Questions tagged [vacuum]

VACUUM is a PostgreSQL command for cleaning up dead rows from the database.

VACUUM is a PostgreSQL command for cleaning up dead rows from the database.

Because PostgreSQL uses multiversion concurrency control (MVCC), rows that are obsolete due to updates or deletion of rows are internally retained so that other concurrent transactions can continue to use the version of the database that existed at the time said transactions began. Eventually, these rows become obsolete, or dead. VACUUM removes these rows from the indexes and marks the space as usable for future transactions. Vacuuming is also required to advance the frozen XID required to properly keep track of past and pending transactions.

By default, an autovacuum daemon handles this automatically, vacuuming the database periodically to clean up dead rows as needed. This autovacuum daemon can be adjusted as appropriate or disabled altogether and replaced with VACUUM operations scheduled through the operating system.

VACUUM FULL performs a complete vacuum of the tables by rewriting them completely (as of PostgreSQL 9.0) to reclaim all space in dead rows, instead of simply marking the space as available. However, this operation requires an access-exclusive lock which prevents all access to each table as it undergoes a full vacuum, requires a significant amount of disk space as a full extra copy of the table is required, and can take a very long time to complete. This is not done by the autovacuum daemon and should only be performed when truly necessary.

For more information on vacuuming, see the Routine Vacuuming section of the PostgreSQL manual.

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Do I need to REINDEX and VACUUM a table after deleting lots of rows?

I am running a PostgreSQL database that has several tables which store logging information. This information is for reporting purposes only and gets dumped to a file and deleted from the database if older than 30 days. There can be millions of rows…
cowgod
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DB Full Vacuum, Cluster, Analyze - in which order?

I have a huge (~150 GBytes) postgresql database whose performance has dropped during the last weeks. In order to improve performance, I intend to perform FULL VACUUM, CLUSTER and ANALYZE. In which order should I perform these operations? I don't…
Adam Matan
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postgresql track counts and autovacuum is not working

In the startup log entries indicate the autovacuum not working. I query the pg_stat_user_tables table and the last_vacuum and last_autovacuum columns are empty in spite of the vacuum query I ran just before. Connecting pgadmin to the database gives…
Bart Dirks
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How do I know if the autovacuumer in postgres 8.3 is actually working?

I have a couple of postgres 8.3 databases, and they are showing symptoms of lack of vacuuming. I've checked the config, and they are in the default state of having the autovacummer turned on. Also, I see in my postgres logs "autovacuum launcher…
jedberg
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postgres vacuum

Ok guys, I've moved to a new company and I see they have a single PostgreSQL database here to run OpenNMS. I'm a MySQL person, not familiar at all with PostgreSQL, but I've at least learned how to run psql and postgres -D to get in single user…
Benny B
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journalctl vacuum not working

I recently started using Fedora 25 and I'm trying to clear the journal logs manually but it's not working. For example: $ journalctl --disk-usage Archived and active journals take up 24.0M on disk. I try to clear with: $ journalctl…
synkro
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Any particular vacuum policy to increase performance using Drupal with PostgreSQL?

I'm running Drupal 7 with PostgreSQL as a Q&A (with a lot of nodes inserts/updates and several contrib modules). Do you, dba admins, recommand any particular pgsql vacuum policy on particular default tables ?
Bao
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Vacuum Full can not delete files because disk full having 5g free

I lately ran out of disk space. I deleted some old data-rows from the CMS database. I have noticed that the free disk space did not grow as expected. I searched in serverfault and found that VACUUM FULL; command. Unfortunately I am unable to run…
Grim
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pgagent job for routine vacuum with bash script

I was expected to create routine vacuuming to be able to schedule the vacuum at less busy hours. I have been searching for a means to routinely vacuum the tables that have not been vacuumed for x days. Postgresql allows you to vacuum full. Which…
Bart Dirks
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Running VACUUM on all tables matching a certain condition

I have are large-ish database which consists of 100+ tables. A few of these tables are so big that running VACUUM on them takes a couple of hours, so I don't want to run it on these tables. Is there any way to run VACUUM with a dynamic list of…
nip3o
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Why is autovacuum using so much IO when running on a partition's master table after upgrading PosgreSQL from 8.4 to 9.1?

We have an application where we are collecting timestamp-based data. Since a month of data goes over 30M rows (and growing each month), we decided to partition the data on an year-and-month basis. We basically have one master table and partition…
Vlad
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Postgresql-8.4 auto vacuum is enabled to get the best performance

I want know which one is good to follow whether auto vacuum or vacuum manually. Right now we are following manually in cron jobs, but sometimes it gets struck to vaccum on particular tables. so we are thinking about the auto vacuum. does it give…
sathish
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