Horton

Re: reloption to prevent VACUUM from truncating empty pages at the end of relation

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Alvaro Herrera <alvherre@alvh.no-ip.org>, Fujii Masao <masao.fujii@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2018-04-17T19:12:26Z
Lists: pgsql-hackers

Commits

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

  1. Add TRUNCATE parameter to VACUUM.

  2. Add vacuum_truncate reloption.

  3. Allow VACUUM to be run with index cleanup disabled.

On 2018-04-17 15:09:18 -0400, Tom Lane wrote:
> Alvaro Herrera <alvherre@alvh.no-ip.org> writes:
> > Andres was working on a radix tree structure to fix this problem, but
> > that seems to be abandoned now, and it seems a major undertaking.

I hope to re-ignite work on that later in the v12 cycle. But
realistically that means it's not going to be mergable for v12.


> > While I agree that the proposed solution is a wart, it seems much
> > better than no solution at all.  Can we consider Fujii's proposal as
> > a temporary measure until we fix shared buffers?  I'm +1 on it
> > myself.
> 
> Once we've introduced a user-visible reloption it's going to be
> practically impossible to get rid of it, so I'm -1.

It's not much work to maintain though? And even the brief AEL lock can
cause troubles, leaving the scan aside. So I'm like +0.1 or such.

Greetings,

Andres Freund