Re: Failure in contrib test _int on loach

Heikki Linnakangas <hlinnaka@iki.fi>

From: Heikki Linnakangas <hlinnaka@iki.fi>
To: Anastasia Lubennikova <a.lubennikova@postgrespro.ru>, pgsql-hackers@lists.postgresql.org
Date: 2019-04-10T15:25:58Z
Lists: pgsql-hackers
On 09/04/2019 19:11, Anastasia Lubennikova wrote:
> 05.04.2019 19:41, Anastasia Lubennikova writes:
>> In attachment, you can find patch with a test that allows to reproduce
>> the bug not randomly, but on every run.
>> Now I'm trying to find a way to fix the issue.
> 
> The problem was caused by incorrect detection of the page to insert new
> tuple after split.
> If gistinserttuple() of the tuple formed by gistgetadjusted() had to
> split the page, we must to go back to the parent and
> descend back to the child that's a better fit for the new tuple.
> 
> Previously this was handled by the code block with the following comment:
> 
> * Concurrent split detected. There's no guarantee that the
> * downlink for this page is consistent with the tuple we're
> * inserting anymore, so go back to parent and rechoose the best
> * child.
> 
> After introducing GistBuildNSN this code path became unreachable.
> To fix it, I added new flag to detect such splits during indexbuild.

Isn't it possible that the grandparent page is also split, so that we'd 
need to climb further up?

- Heikki



Commits

  1. Detect internal GiST page splits correctly during index build.

  2. Generate less WAL during GiST, GIN and SP-GiST index build.