Re: WIP: explain analyze with 'rows' but not timing - Mailing list pgsql-hackers

From Tom Lane
Subject Re: WIP: explain analyze with 'rows' but not timing
Date
Msg-id 8630.1324677749@sss.pgh.pa.us
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In response to Re: WIP: explain analyze with 'rows' but not timing  (Pavel Stehule <pavel.stehule@gmail.com>)
Responses Re: WIP: explain analyze with 'rows' but not timing  (Pavel Stehule <pavel.stehule@gmail.com>)
List pgsql-hackers
Pavel Stehule <pavel.stehule@gmail.com> writes:
> 2011/12/23 Tom Lane <tgl@sss.pgh.pa.us>:
>> Tomas Vondra <tv@fuzzy.cz> writes:
>>> The motivation for this patch was that collection timing data often
>>> causes performance issues and in some cases it's not needed. But is this
>>> true for row counts?

>> Perhaps more to the point, is there a use case for collecting timing
>> data without row counts?  I find it hard to visualize a valid reason.

> yes - a searching of bad prediction

No, because timing alone proves nothing at all.  The machine could just
have been overloaded.
        regards, tom lane


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