| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Rajesh Kumar Mallah <mallah(at)trade-india(dot)com> |
| Cc: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Why performance improvement on converting subselect |
| Date: | 2003-07-31 03:21:38 |
| Message-ID: | 27221.1059621698@sss.pgh.pa.us |
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| Lists: | pgsql-performance |
Rajesh Kumar Mallah <mallah(at)trade-india(dot)com> writes:
> Below are the plans for two cases. I dont know how to read them accurately
> can u please explain them.
Well, they're the same plan, as far as they go. I suppose that the
runtime difference must come from choosing a different plan inside the
most_recent_edition() function, which we cannot see in the explain
output. As before, turning on logging of verbose query plans is the
only way to look at what the function is doing.
> Also can anyone point to some documentation
> oriented towards understanding explain analyze output?
http://www.postgresql.org/docs/view.php?version=7.3&idoc=0&file=performance-tips.html
regards, tom lane
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