On 13/03/2020 15:15, Ron wrote:
This is why I'd VACUUM FULL in a planned manner, one or two tables at a
time, and *locally* from crontab.
That's not really viable on any remotely busy system: VACUUM FULL claims
exclusive table locks, causing queries to hang
(https://www.postgresql.org/docs/current/sql-vacuum.html#NOTES mentions
this too).
Tools like pg_repack can do some live shrinking.
I've also had some success at reclaiming space without large scale locks
by carefully crafting some atomic DELETE + INSERT in order to force
tuples from the tail end into gaps at lower CTIDs (physical page
address) that were made available by previous plain VACUUMs - regular
VACUUM will clip data files if all the tuples beyond a given offset are
dead.
On 3/13/20 8:41 AM, Zwettler Markus (OIZ) wrote:
We did a "vacuum full" on a database which had been interrupted by a
network outage.
We found the database size doubled afterwards.
Autovacuum also found a lot of orphaned tables afterwards.
The ophan temp objects went away after a cluster restart while the db
size remained doubled.
Any idea?
Postgres 9.6.17
--
Angular momentum makes the world go 'round.
--
Regards
Fabio Ugo Venchiarutti
OSPCFC Network Engineering Dpt.
Ocado Technology
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