Re: Two different execution plan for the same request

От: JOUANIN Nicolas (44)
Тема: Re: Two different execution plan for the same request
Дата: ,
Msg-id: 4C34648B.1010103@dgfip.finances.gouv.fr
(см: обсуждение, исходный текст)
Ответ на: Re: Two different execution plan for the same request  (Guillaume Smet)
Ответы: Re: Two different execution plan for the same request  (Matthew Wakeling)
Список: pgsql-performance

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Two different execution plan for the same request  ("JOUANIN Nicolas (44)", )
 Re: Two different execution plan for the same request  (Yeb Havinga, )
  Re: Two different execution plan for the same request  ("JOUANIN Nicolas (44)", )
   Re: Two different execution plan for the same request  (Yeb Havinga, )
   Re: Two different execution plan for the same request  (Guillaume Smet, )
    Re: Two different execution plan for the same request  ("JOUANIN Nicolas (44)", )
     Re: Two different execution plan for the same request  (Matthew Wakeling, )

<font size="-1"><font face="Arial">It seems to work fine (same execution plan and less duration) after :<br />  -
settingdefault_statistics_target to 100<br />  - full vacuum with analyze<br />  - reindexdb<br /><br /> Thanks.<br
/></font></font><br/><br /> -------- Message original --------<br /> Sujet : Re: [PERFORM] Two different execution plan
forthe same request<br /> De : Guillaume Smet <a class="moz-txt-link-rfc2396E"
href="mailto:"><></a><br/> Pour : JOUANIN Nicolas (44) <a
class="moz-txt-link-rfc2396E"
href="mailto:"><></a><br/> Copie à :
YebHavinga <a class="moz-txt-link-rfc2396E" href="mailto:"><></a>, <a
class="moz-txt-link-abbreviated"href="mailto:"></a><br
/>Date : 07/07/2010 10:59<br /><blockquote cite="mid:"
type="cite"><prewrap="">Hi Nicolas,
 

On Wed, Jul 7, 2010 at 10:47 AM, JOUANIN Nicolas (44)
<a class="moz-txt-link-rfc2396E"
href="mailto:"><></a>wrote:
</pre><blockquotetype="cite"><pre wrap="">There were no modification made on the database except a restart yesterday
eveningand a vacuumdb --analyse ran at night.   </pre></blockquote><pre wrap="">
 
It's not really surprising considering you probably kept the
default_statistics_target to 10 (it's the default in 8.3).

Consider raising it to 100 in your postgresql.conf (100 is the default
for newer versions), then reload, and run a new ANALYZE.

You might need to set it higher on specific columns if you have a lot
of data and your data distribution is weird.

And, btw, please upgrade to the latest 8.3.x.

HTH
 </pre></blockquote><br />

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