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Re: Deleting older versions in unique indexes to avoid page splits

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Peter Geoghegan <pg@bowt.ie>, Victor Yegorov <vyegorov@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-01-20T05:20:21Z
Lists: pgsql-hackers 
Hi,

On 2021-01-20 09:24:35 +0530, Amit Kapila wrote:
> I feel extending the deletion mechanism based on the number of LP_DEAD
> items sounds more favorable than giving preference to duplicate
> items. Sure, it will give equally good or better results if there are
> no long-standing open transactions.

There's a lot of workloads that never set LP_DEAD because all scans are
bitmap index scans. And there's no obvious way to address that. So I
don't think it's wise to purely rely on LP_DEAD.

Greetings,

Andres Freund

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Enhance nbtree index tuple deletion.

  2. Pass down "logically unchanged index" hint.

  3. Fix index deletion latestRemovedXid bug.

  4. Deprecate nbtree's BTP_HAS_GARBAGE flag.