Re: order of nested loop

From: Joseph Shraibman <joseph(at)xtenit(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-general(at)postgreSQL(dot)org
Subject: Re: order of nested loop
Date: 2003-06-17 22:55:10
Message-ID: 3EEF9C4E.6070300@xtenit.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-general

Tom Lane wrote:
> Joseph Shraibman <jks(at)selectacast(dot)net> writes:
>
>>How do I read that? Is it creating a hash out of the data in d, then
>>going through u doing a join?
>
>
> Yeah. Given the numbers of rows involved, the plan seems pretty
> reasonable --- I doubt you can do a lot better within the context
> you're showing here. To make it faster you'll have to find a way
> to not need to look at all the rows.
>
> regards, tom lane
Well there is no reason for it to look at all the rows in d, since it has a filter on u
that should produce much less rows than there on in d. In both the plan and the actual
the rows returned from u are less than the rows from d

In response to

Responses

Browse pgsql-general by date

  From Date Subject
Next Message Arguile 2003-06-17 23:00:07 Re: Link to Bruce M's fs performance tuning doc
Previous Message nikolaus 2003-06-17 22:45:38 Re: [PERFORM] Interesting incosistent query timing