Re: Help interpreting explain analyze output - Mailing list pgsql-performance

From Tom Lane
Subject Re: Help interpreting explain analyze output
Date
Msg-id 28313.1092593619@sss.pgh.pa.us
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In response to Help interpreting explain analyze output  (Ole Tange <postgresql.org@tange.dk>)
Responses Re: Help interpreting explain analyze output
List pgsql-performance
Ole Tange <postgresql.org@tange.dk> writes:
> As I read it the output tells me what was done during the milliseconds:

No, you have a fundamental misconception here.  The notation means that
the first output row from a plan step was delivered after X
milliseconds, and the last row after Y milliseconds.

The "gap" you are looking at is the time to do the Sort (since a sort
can't deliver the first output row until it's finished the sort).

It is gonna take a while to sort 175000 rows ... but possibly increasing
sort_mem would help.

            regards, tom lane

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