Re: Fix for parallel BTree initialization bug

Amit Kapila <amit.kapila16@gmail.com>

From: Amit Kapila <amit.kapila16@gmail.com>
To: "Jameson, Hunter 'James'" <hunjmes@amazon.com>
Cc: "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2020-09-09T13:14:08Z
Lists: pgsql-hackers
On Tue, Sep 8, 2020 at 11:55 PM Jameson, Hunter 'James'
<hunjmes@amazon.com> wrote:
>
> Hi, I ran across a small (but annoying) bug in initializing parallel BTree scans, which causes the parallel-scan state machine to get confused.
>
>
> To reproduce, you need a query that:
>
>
>
> 1. Executes parallel BTree index scan;
>
> 2. Has an IN-list of size > 1;
>
> 3. Has an additional index filter that makes it impossible to satisfy the
>
>     first IN-list condition.
>
>
>
> (We encountered such a query, and therefore the bug, on a production instance.)
>
>

I think I can understand what you are pointing out here but it would
be great if you can have a reproducible test case because that will
make it apparent and we might want to include that in the regression
tests if possible.

-- 
With Regards,
Amit Kapila.



Commits

  1. Update parallel BTree scan state when the scan keys can't be satisfied.

  2. btree: Support parallel index scans.