Horton

Re: [PATCH] Improve amcheck to also check UNIQUE constraint in btree index.

Mark Dilger <mark.dilger@enterprisedb.com>

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From: Mark Dilger <mark.dilger@enterprisedb.com>
To: Pavel Borisov <pashkin.elfe@gmail.com>
Cc: Anastasia Lubennikova <a.lubennikova@postgrespro.ru>, Postgres hackers <pgsql-hackers@lists.postgresql.org>, Peter Geoghegan <pg@bowt.ie>
Date: 2021-03-01T19:21:59Z
Lists: pgsql-hackers

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: Optimize speed of checking for unique constraint violation

  2. amcheck: Report an error when the next page to a leaf is not a leaf

  3. amcheck: Don't load the right sibling page into BtreeCheckState

  4. amcheck: Refactoring the storage of the last visible entry

  5. Teach contrib/amcheck to check the unique constraint violation

  6. Add macros in hash and btree AMs to get the special area of their pages


> On Feb 9, 2021, at 10:43 AM, Pavel Borisov <pashkin.elfe@gmail.com> wrote:
> 
> вт, 9 февр. 2021 г. в 01:46, Mark Dilger <mark.dilger@enterprisedb.com>:
> 
> 
> > On Feb 8, 2021, at 2:46 AM, Pavel Borisov <pashkin.elfe@gmail.com> wrote:
> > 
> > 0002 - is a temporary hack for testing. It will allow inserting duplicates in a table even if an index with the exact name "idx" has a unique constraint (generally it is prohibited to insert). Then a new amcheck will tell us about these duplicates. It's pity but testing can not be done automatically, as it needs a core recompile. For testing I'd recommend a protocol similar to the following:
> > 
> > - Apply patch 0002
> > - Set autovaccum = off in postgresql.conf
> 
> Thanks Pavel and Anastasia for working on this!
> 
> Updating pg_catalog directly is ugly, but the following seems a simpler way to set up a regression test than having to recompile.  What do you think?
> 
> Very nice idea, thanks!
> I've made a regression test based on it. PFA v.2 of a patch. Now it doesn't need anything external for testing.

If bt_index_check() and bt_index_parent_check() are to have this functionality, shouldn't there be an option controlling it much as the option (heapallindexed boolean) controls checking whether all entries in the heap are indexed in the btree?  It seems inconsistent to have an option to avoid checking the heap for that, but not for this.  Alternately, this might even be better coded as its own function, named something like bt_unique_index_check() perhaps.  I hope Peter might advise?

The regression test you provided is not portable.  I am getting lots of errors due to differing output of the form "page lsn=0/4DAD7E0".  You might turn this into a TAP test and use a regular expression to check the output.

—
Mark Dilger
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