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Re: Query is slower with a large proportion of NULLs in several columns - Mailing list pgsql-performance

From Tom Lane
Subject Re: Query is slower with a large proportion of NULLs in several columns
Date
Msg-id 2704544.1640062888@sss.pgh.pa.us
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In response to Re: Query is slower with a large proportion of NULLs in several columns  (Justin Pryzby <pryzby@telsasoft.com>)
Responses Re: Query is slower with a large proportion of NULLs in several columns
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Justin Pryzby <pryzby@telsasoft.com> writes:
> On Mon, Dec 20, 2021 at 08:11:42PM -0800, Lars Bergeson wrote:
>> Still taking 10X more I/O to read the smaller table. Very odd.

> If I'm not wrong, it's even worse than that ?
> It takes 20 or 30sec to run the query - but it says the associated I/O times
> are ~500sec or ~6000sec ?

It would help if somebody had labeled the units of I/O Time
... but I'm guessing those are microsec vs. the millisec
of the other times, because otherwise it's completely wrong.

            regards, tom lane

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