Horton

Re: Multiple FPI_FOR_HINT for the same block during killing btree index items

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: James Coleman <jtc331@gmail.com>
Cc: Masahiko Sawada <masahiko.sawada@2ndquadrant.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>, Álvaro Herrera <alvherre@2ndquadrant.com>
Date: 2020-04-10T02:07:45Z
Lists: pgsql-hackers 
On Thu, Apr 9, 2020 at 6:47 PM James Coleman <jtc331@gmail.com> wrote:
> I believe the write pattern to this table likely looks like:
> - INSERT
> - UPDATE
> - DELETE
> for every row. But tomorrow I can do some more digging if needed.

The pg_stats.null_frac for the column/index might be interesting here. I
believe that Active Record will sometimes generate created_at columns
that sometimes end up containing NULL values. Not sure why.


--
Peter Geoghegan

Commits

  1. Avoid killing btree items that are already dead