Re: TRAP: failed Assert("offsets[i] > offsets[i - 1]"), File: "tidstore.c"

On Thu, Apr 16, 2026 at 1:26 AM Andrei Lepikhov <lepihov(at)gmail(dot)com> wrote:
>
> On 16/04/2026 10:11, Masahiko Sawada wrote:
> > On Thu, Apr 16, 2026 at 12:13 AM Andrei Lepikhov <lepihov(at)gmail(dot)com> wrote:
> > -- Random TIDs test. The offset numbers are randomized and must be --
> > unique and ordered. INSERT INTO hideblocks (blockno) SELECT
> > do_set_block_offsets(blkno, array_agg(DISTINCT greatest((random() *
> > :maxoffset)::int, 1))::int2[]) FROM generate_series(1, 100)
> > num_offsets, generate_series(1000, 1100, 1) blkno GROUP BY blkno;
>
> Alright, I used an explicit sort in reverse order to make sure the test is
> stable. I usually create modules that may change different paths, costs, and
> orders, and using random can make things unpredictable. But for this specific
> test, I don't see any risk.
>
> >
> > While I agree that we need to sort the offset numbers, I think it
> > would be better to make sure the offset numbers in the array to be
> > sorted in a test_tidstore.sql file where required, instead of doing so
> > for all cases.
>
> I'm not sure I follow. Are you saying that do_set_block_offsets shouldn't sort
> the incoming offsets?

No, I wanted to mean that if we sort the given array in
do_set_block_offsets() as the proposed patch does, we end up always
sorting arrays even if the sorting is no actually required (e.g., when
executing "SELECT do_set_block_offsets(1,
array[1,2,3,4,100]::int2[]);"). So an alternative idea to stabilize
the regression test would be to create a SQL function to return a list
of sorted offsets and use it where it's required. While the patch gets
a little bigger, It would also help simplify the tests somewhat by
removing the redundant codes. I've attached the patch for this idea.

Regards,

--
Masahiko Sawada
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