| From: | Jean-Christophe BOGGIO <postgresql(at)thefreecat(dot)org> |
|---|---|
| To: | David Rowley <dgrowleyml(at)gmail(dot)com> |
| Cc: | "pgsql-performance(at)lists(dot)postgresql(dot)org" <pgsql-performance(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: Why isn't PG using an index-only scan? |
| Date: | 2025-09-18 07:45:13 |
| Message-ID: | 63d65775-0130-4c5c-a151-8d7728b6d4e8@thefreecat.org |
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| Thread: | |
| Lists: | pgsql-performance |
Thanks David,
Le 18/09/2025 à 09:20, David Rowley a écrit :
> Yes. Since *all* records of "oeu" are required and they're not
> required in any particular order, then Seq Scan should be the fastest
> way to access those records.
Ok but then why is it doing it on the AD table? Is it because of the
number of rows?
> 5 hours seems very slow for the estimated number of records. Have you
> tried running the SELECT using EXPLAIN ANALYZE without the INSERT
> part? Even if the 84 million Merge Join row estimate is accurate, 5
> hours seems excessively long.
I tried this, it took 1 second. And then I discovered that I had an old
trigger on the copyrightad table.
The insert took 2 seconds.
Very sorry for wasting your time and thanks again for putting me on the
right track.
Have a great day!
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