Re: Bad performance on simple query

От: ries van Twisk
Тема: Re: Bad performance on simple query
Дата: ,
Msg-id: F15CC409-35D6-46D5-9100-83D6E8958A77@rvt.dds.nl
(см: обсуждение, исходный текст)
Ответ на: Re: Bad performance on simple query  ("Scott Marlowe")
Список: pgsql-performance

Скрыть дерево обсуждения

Bad performance on simple query  (Dimi Paun, )
 Re: Bad performance on simple query  (Alan Hodgson, )
 Re: Bad performance on simple query  ("Scott Marlowe", )
  Re: Bad performance on simple query  (Dimi Paun, )
   Re: Bad performance on simple query  ("Scott Marlowe", )
    Re: Bad performance on simple query  (Dimi Paun, )
     Re: Bad performance on simple query  ("Scott Marlowe", )
      Re: Bad performance on simple query  (ries van Twisk, )
      Re: Bad performance on simple query  (Dimi Paun, )
       Re: Bad performance on simple query  ("Dave Page", )

On Nov 17, 2008, at 12:40 PM, Scott Marlowe wrote:

> On Mon, Nov 17, 2008 at 10:31 AM, Dimi Paun <> wrote:
>>
>> On Mon, 2008-11-17 at 10:16 -0700, Scott Marlowe wrote:
>>> Ahhh.  Keep in mind that if you just run the query, pgadminIII will
>>> tell you how long it took to run AND return all the data across the
>>> network, so it will definitely take longer then.  But most of that's
>>> network io wait so it's not a real issue unless you're saturating
>>> your
>>> network.
>>
>> But that is brutal -- there's no way it can take 20ms for a request
>> across an unloaded network.
>>
>> Moreover, I got something like this:
>>
>>           pgadminIII | pgsql
>> w/o index:     45ms      0.620ms
>> w/ index       20ms      0.091ms
>>
>> How now I try to replicate, and I get 45ms in both cases. This is
>> very misleading...
>
> I'm guessing a fair bit of that time is pgadminIII prettifying the
> output for you, etc.  I.e. it's not all transfer time.  Hard to say
> without hooking some kind of profiler in pgadminIII.  Is psql running
> local and pgadminIII remotely?  Or are they both remote?  If both psql
> and pgadminIII are remote (i.e. same basic circumstances) then it's
> got to be a difference in the client causing the extra time.  OR is
> this output of explain analyze?
>

Side note: I haven't seen pgAdminIII never show a time below 20ms (the
time on the bottom right corner).

When I do a query like this : select 1; it takes according to
pgAdminIII around 20ms. (whatever that time is)

what I normally do to find my real query time is put and explain
analyse in front of my query to know to real query time.

Ries








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