| From: | "Scott Marlowe" <scott(dot)marlowe(at)gmail(dot)com> |
|---|---|
| To: | "Nitin Verma" <nitinverma(at)azulsystems(dot)com> |
| Cc: | pgsql-general(at)postgresql(dot)org |
| Subject: | Re: What kind of locks does vacuum process hold on the db? |
| Date: | 2007-08-30 04:59:04 |
| Message-ID: | dcc563d10708292159l978f750gb01ccb19036d3c64@mail.gmail.com |
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| Lists: | pgsql-general |
On 8/29/07, Nitin Verma <nitinverma(at)azulsystems(dot)com> wrote:
> What kind of locks does it hold on the db? Table level / Row level /
> AccessExclusiveLock ?
> Is there a document that details vacuum process, and its internals?
>
>
> Use case: I am doing a vacuum {all full analyze} on a postgres 8.1 hosting
> two user databases. For this I am using ${pg-home}/bin/vacuumdb, not direct
> SQLs. Parallel to this I am running transaction on both user-DBs.
> Observation:
> Transactions don't pause while vacuum is running. (Odd, how come?)
Why are you doing FULL vacuums? Is there some problem that regular
vacuums aren't solving?
> After this I tried two vacuums in parallel but those lock each other.
Yes, vacuum full takes a hard lock on a table.
Vacuum full is to be avoided.
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