Re: Running update in chunks?

From: Jasen Betts <jasen(at)xnet(dot)co(dot)nz>
To: pgsql-general(at)postgresql(dot)org
Subject: Re: Running update in chunks?
Date: 2013-01-27 10:04:41
Message-ID: ke2u3p$oue$1@gonzo.reversiblemaps.ath.cx
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On 2013-01-25, Tim Uckun <timuckun(at)gmail(dot)com> wrote:
>> I agree that seems like the most likely cause. Each update to the
>> row holding the hstore column requires adding new index entries for
>> all the hstore elements, and autovacuum will need to clean up the
>> old ones in the background. The best solution would be to either
>> normalize the data instead of using hstore, or move the hstore to a
>> separate table which is referenced by some sort of ID from the
>> frequently-updated table.
>
>
> That's very interesting. I can certainly split up the table, no big
> deal there. So would the index be redone even if I am not updating
> the hstore field itself?

Absolutely! see MVCC.

http://www.postgresql.org/docs/current/static/mvcc-intro.html

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