Re: Weird query plan

From: Dmitry Tkach <dmitry(at)openratings(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pg_general <pgsql-general(at)postgresql(dot)org>
Subject: Re: Weird query plan
Date: 2003-09-17 20:33:29
Message-ID: 3F68C519.7050507@openratings.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-general

Tom Lane wrote:

>Dmitry Tkach <dmitry(at)openratings(dot)com> writes:
>
>
>>I now have the same problem with it, but the other way around - the
>>query with a condition on a runs quickly, and one with a condition on b
>>does not... and the query plans are the same, and have a as outer table...
>>
>>
>
>Hm. You know, I wonder whether the query plans really are the same.
>One of the reasons why 7.3 and later show the qual conditions is that
>it was too easy to fall into the trap of assuming that plans of the same
>structure had the same conditions. Try doing "explain verbose" and look
>to see if the plans look the same at that level of detail.
>
> regards, tom lane
>
>
I am afraid that's too much detail for me to look at :-)
I have no clue what all that stuff means :-(

But I am pretty sure they are the same - I did not know whether the
first one or the second was supposed to be the outer relation, so I
looked at it in the debugger...
So, I know that in both cases it was using b for the outer loop...

Thanks!
Dima

In response to

Responses

Browse pgsql-general by date

  From Date Subject
Next Message Dmitry Tkach 2003-09-17 20:39:59 Re: Weird query plan
Previous Message Network Administrator 2003-09-17 20:28:02 Re: State of Beta (2)