Re: Inserts in 'big' table slowing down the database

From: Greg Williamson <gwilliamson39(at)yahoo(dot)com>
To: Stefan Keller <sfkeller(at)gmail(dot)com>, Ivan Voras <ivoras(at)freebsd(dot)org>
Cc: "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Inserts in 'big' table slowing down the database
Date: 2012-10-02 00:35:58
Message-ID: 1349138158.88943.YahooMailNeo@web125905.mail.ne1.yahoo.com
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Stefan --

----- Original Message -----
> From: Stefan Keller <sfkeller(at)gmail(dot)com>
> To: Ivan Voras <ivoras(at)freebsd(dot)org>
> Cc: pgsql-performance(at)postgresql(dot)org
> Sent: Monday, October 1, 2012 5:15 PM
> Subject: Re: [PERFORM] Inserts in 'big' table slowing down the database
>
> Sorry for the delay. I had to sort out the problem (among other things).
>
> It's mainly about swapping.
>
> The table nodes contains about 2^31 entries and occupies about 80GB on
> disk space plus index.
> If one would store the geom values in a big array (where id is the
> array index) it would only make up about 16GB, which means that the
> ids are dense (with few deletes).
> Then updates come in every hour as bulk insert statements with entries
> having ids in sorted manner.
> Now PG becomes slower and slower!
> CLUSTER could help - but obviously this operation needs a table lock.
> And if this operation takes longer than an hour, it delays the next
> update.
>
> Any ideas? Partitioning?

pg_reorg if you have the space might be useful in doing a cluster-like action:
 <http://reorg.projects.postgresql.org/>

Haven't followed the thread so I hope this isn't redundant.

Partitioning might work if you can create clusters that are bigger than 1 hour -- too many partitions doesn't help.

Greg Williamson

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