From: Christo Du Preez <christo@mecola.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-performance@postgresql.org
Subject: Re: test / live environment, major performance difference
Date: Tue, 12 Jun 2007 18:59:16 +0200
Message-ID: <466ED0E4.3040803@mecola.com> (raw)
In-Reply-To: <8385.1181664586@sss.pgh.pa.us>
References: <466EA078.20601@mecola.com>
<8385.1181664586@sss.pgh.pa.us>
Yes, I have just about tried every combination of vacuum on the
database. Just to make 100% sure.
Tom Lane wrote:
> Christo Du Preez <christo@mecola.com> writes:
>
>> On my laptop the explain analyze looks like this:
>>
>
>
>> "Index Scan using fki_layertype_parentid on layertype (cost=0.00..8.27
>> rows=1 width=109)"
>> " Index Cond: (parentid = 300)"
>>
>
> OK ...
>
>
>> and on the problem server:
>>
>
>
>> "Seq Scan on layertype (cost=0.00..20.39 rows=655 width=110)"
>> " Filter: (parentid = 300)"
>>
>
> The server thinks that every row of the table matches the WHERE clause.
> That being the case, it's making the right choice to use a seqscan.
> The question is why is the rows estimate so far off? Have you ANALYZEd
> the table lately?
>
> regards, tom lane
>
>
>
--
Christo Du Preez
Senior Software Engineer
Mecola IT
Mobile: +27 [0]83 326 8087
Skype: christodupreez
Website: http://www.locateandtrade.co.za
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To: pgsql-performance@postgresql.org
Cc: christo@mecola.com, tgl@sss.pgh.pa.us
Subject: Re: test / live environment, major performance difference
In-Reply-To: <466ED0E4.3040803@mecola.com>
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