Re: execute many for each commit

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Alessandro Gagliardi <alessandro(at)path(dot)com>
Cc: pgsql-novice(at)postgresql(dot)org
Subject: Re: execute many for each commit
Date: 2012-02-17 23:16:27
Message-ID: 6801.1329520587@sss.pgh.pa.us
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Alessandro Gagliardi <alessandro(at)path(dot)com> writes:
> This is really more of a psycopg2 than a PostgreSQL question per se, but
> hopefully there are a few Pythonistas on this list who can help me out. At
> a recent PUG meeting I was admonished on the folly of committing after
> every execute statement (especially when I'm executing hundreds of inserts
> per second). I was thinking of batching a bunch of execute statements (say,
> 1000) before running a commit but the problem is that if any one of those
> inserts fail (say, because of a unique_violation, which happens quite
> frequently) then I have to rollback the whole batch. Then I'd have to come
> up with some logic to retry each one individually or something similarly
> complicated.

Subtransactions (savepoints) are considerably cheaper than full
transactions. Alternatively you could consider turning off
synchronous_commit, if you don't need a guarantee that COMMIT means "it's
already safely on disk".

regards, tom lane

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