Re: Performance problems with postgres and null Values?

From: Albe Laurenz <laurenz(dot)albe(at)wien(dot)gv(dot)at>
To: 'Sven Kerkling *EXTERN*' <kerkling(at)bds-online(dot)com>, 'Merlin Moncure' <mmoncure(at)gmail(dot)com>
Cc: 'postgres performance list' <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Performance problems with postgres and null Values?
Date: 2016-04-25 08:08:22
Message-ID: A737B7A37273E048B164557ADEF4A58B53843FFE@ntex2010i.host.magwien.gv.at
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Sven Kerkling wrote:
> This one ist the burden, running at least 100 seconds:
>
> SELECT b.id, b.status
> FROM export b, masterNew mb
> WHERE mb.sperre IS NULL
> AND mb.status IS NULL
> AND b.id = mb.id
> LIMIT 100;
>
> http://explain.depesz.com/s/eAqG

I think the problem is here:

Bitmap Index Scan on masterNew_2016_pi_idx (cost=0.00..5.34 rows=181 width=0) (actual time=805.225..805.225 rows=4,764,537 loops=1)

Perhaps you should ANALYZE "masterNew" to get better statistics.

Yours,
Laurenz Albe

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