Re: Index-only scan returns incorrect results when using a composite GIST index with a gist_trgm_ops column.

At Thu, 01 Mar 2018 15:39:18 -0500, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote in <22609(dot)1519936758(at)sss(dot)pgh(dot)pa(dot)us>
> Kyotaro HORIGUCHI <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp> writes:
> > At Wed, 24 Jan 2018 00:13:51 +0300, Sergei Kornilov <sk(at)zsrv(dot)org> wrote in <348951516742031(at)web54j(dot)yandex(dot)ru>
> >> Should we also make backport to older versions? I test on REL_10_STABLE - patch builds and works ok, but "make check" fails on new testcase with error:
> > CREATE INDEX ON t USING gist (a test_inet_ops, a inet_ops);
> > + ERROR: missing support function 4 for attribute 1 of index "t_a_a1_idx"
> >> and with different explain results.
>
> > Thank you for checking that. d3a4f89 allowed that and
> > inet_gist_decompress is removed at the same time. Unfortunately I
> > didn't find a type on master that has both decompress and fetch
> > methods so I prefer to split the regression patch among target
> > versions.
>
> I pushed this fix with minor adjustments. I did not like the proposed

Thank you.

> regression test at all: it was overcomplicated and the need for different
> versions for different back branches wasn't fun either. After some poking
> around I found that the bug could be exhibited using just btree_gist's
> gist_inet_ops, since the core inet_ops class indexes the same datatype and
> it does have a fetch function. So I added a test case in btree_gist.

Ah, It wasn't in my sight to test core in contrib. Thanks for
improving it.

regards,

--
Kyotaro Horiguchi
NTT Open Source Software Center