| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Frédéric Yhuel <frederic(dot)yhuel(at)dalibo(dot)com> |
| Cc: | "pgsql-performance(at)lists(dot)postgresql(dot)org" <pgsql-performance(at)lists(dot)postgresql(dot)org>, Jehan-Guillaume de Rorthais <jgdr(at)dalibo(dot)com>, Christophe Courtois <christophe(dot)courtois(at)dalibo(dot)com>, Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at> |
| Subject: | Re: Indexes on expressions with multiple columns and operators |
| Date: | 2025-09-18 16:40:39 |
| Message-ID: | 1972974.1758213639@sss.pgh.pa.us |
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| Lists: | pgsql-performance |
I wrote:
> Sigh ... so the answer is this used to work (since commit 39df0f150)
> and then I carelessly broke it in commit a391ff3c3. If you try this
> test case in versions 9.5..11 you get a spot-on rowcount estimate.
> Serves me right for not having a test case I guess, but I'm astonished
> that nobody complained sooner.
The attached fixes things so it works like it did pre-a391ff3c3.
I spent some time trying to devise a test case, and was reminded
of why I didn't have one before: it's hard to make a case that
will be robust enough to not show diffs in the buildfarm.
I'll keep thinking about that though.
regards, tom lane
| Attachment | Content-Type | Size |
|---|---|---|
| v1-fix-misfactoring-of-function-selectivity.patch | text/x-diff | 3.1 KB |
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