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Re: Amcheck verification of GiST and GIN

Andrey Borodin <amborodin86@gmail.com>

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From: Andrey Borodin <amborodin86@gmail.com>
To: Peter Geoghegan <pg@bowt.ie>
Cc: Mark Dilger <mark.dilger@enterprisedb.com>, Jose Arthur Benetasso Villanova <jose.arthur@gmail.com>, Andres Freund <andres@anarazel.de>, Andrey Borodin <x4mmm@yandex-team.ru>, Nikolay Samokhvalov <samokhvalov@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2023-03-18T03:40:05Z
Lists: pgsql-hackers 
Hi Peter,

Thanks for the feedback! I'll work on it during the weekend.

On Thu, Mar 16, 2023 at 6:23 PM Peter Geoghegan <pg@bowt.ie> wrote:
>
> existence of a "same" routine hints at some confusion about "equality
> versus equivalence" issues.

Hmm...yes, actually, GiST deals with floats routinely. And there might
be some sorts of NaNs and Infs that are equal, but not binary
equivalent.
I'll think more about it.

gist_get_adjusted() calls "same" routine, which for type point will
use FPeq(double A, double B). And this might be kind of a corruption
out of the box. Because it's an epsilon-comparison, ε=1.0E-06.
GiST might miss newly inserted data, because the "adjusted" tuple was
"same" if data is in proximity of 0.000001 of any previously indexed
point, but out of known MBRs.
I'll try to reproduce this tomorrow, so far no luck.


Best regards, Andrey Borodin.

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. amcheck: Fix posting tree checks in gin_index_check()

  2. amcheck: Fix parent key check in gin_index_check()

  3. amcheck: Fix checks of entry order for GIN indexes

  4. amcheck: Remove unused GinScanItem->parentlsn field

  5. amcheck: Test gin_index_check on a multicolumn index

  6. Remove incidental md5() function use from test

  7. amcheck: Add a GIN index to the CREATE INDEX CONCURRENTLY tests

  8. amcheck: Add a test with GIN index on JSONB data

  9. amcheck: Fix indentation in verify_gin.c

  10. amcheck: Add gin_index_check() to verify GIN index

  11. amcheck: Move common routines into a separate module

  12. Fix grammar in GIN README

  13. Avoid amcheck inline compression false positives.