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Re: Performance views/tables in PostgreSQL?

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On Thu, 22 Mar 2012 12:57:52 +0000, Jasen Betts wrote:


> explain analyze is the most commonly used query performance metric.
> 
> I think there may be something else too.

With all due respect, there is nothing like the Oracle wait interface in 
the free version of PostgreSQL. Nada. Zilch. 
Explain plan answers the question "how will Postgres execute my query". 
The wait interface answers the question "where is the time spent". Note 
that explain plan answers the question about the future and wait 
interface answers the question about the past. Explain plan cannot tell 
you whether your application was waiting for lock, resolving a deadlock 
or simply dealing with a slow disk. It may not even be a database problem 
at all. Java application may have a bug ,causing it to sleep and not wake 
up until kissed by a prince, which doesn't happen that frequently.
Oracle will tell you that it's waiting for the more data from SQL*Net, so 
you can start looking into the application. Postgres will also allow you 
to make that conclusion, but not directly. You will see no activity on 
the server and conclude that there is a problem with the application 
itself.



-- 
http://mgogala.byethost5.com

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Performance views/tables in PostgreSQL? Pol <eff.off.if.you.think.youre.getting.my.email@anon.com> - 2012-03-21 16:18 +0100
  Re: Performance views/tables in PostgreSQL? Mladen Gogala <gogala.mladen@gmail.com> - 2012-03-22 13:16 +0000
  Re: Performance views/tables in PostgreSQL? Jasen Betts <jasen@xnet.co.nz> - 2012-03-22 12:57 +0000
    Re: Performance views/tables in PostgreSQL? Mladen Gogala <gogala.mladen@gmail.com> - 2012-03-23 05:04 +0000

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