Re: Deleting older versions in unique indexes to avoid page splits - Mailing list pgsql-hackers

From Simon Riggs
Subject Re: Deleting older versions in unique indexes to avoid page splits
Date
Msg-id CANP8+jLt6Gf38z-p_FETdSwaCJgK4MskxM_VuRtNM9ZEsqMbeQ@mail.gmail.com
Whole thread Raw
In response to Re: Deleting older versions in unique indexes to avoid page splits  (Peter Geoghegan <pg@bowt.ie>)
Responses Re: Deleting older versions in unique indexes to avoid page splits  (Peter Geoghegan <pg@bowt.ie>)
List pgsql-hackers
On Fri, 23 Oct 2020 at 18:14, Peter Geoghegan <pg@bowt.ie> wrote:

> It's obvious that a page split is more expensive than the delete
> operation (when it works out).

The problem I highlighted is that the average UPDATE latency is x2
what it is on current HEAD. That is not consistent with the reported
TPS, so it remains an issue and that isn't obvious.

> It doesn't need a microbenchmark (and I
> really can't think of one that would make any sense).

I'm asking for detailed timings so we can understand the latency
issue. I didn't ask for a microbenchmark.

I celebrate your results, but we do need to understand the issue, somehow.

-- 
Simon Riggs                http://www.EnterpriseDB.com/



pgsql-hackers by date:

Previous
From: Michael Paquier
Date:
Subject: Re: speed up unicode decomposition and recomposition
Next
From: Stephen Frost
Date:
Subject: Re: [doc] remove reference to pg_dump pre-8.1 switch behaviour