Horton

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

Alvaro Herrera <alvherre@alvh.no-ip.org>

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From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Michael Paquier <michael@paquier.xyz>
Cc: Amit Kapila <amit.kapila16@gmail.com>, Andres Freund <andres@anarazel.de>, Tom Lane <tgl@sss.pgh.pa.us>, Fujii Masao <masao.fujii@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2018-04-19T19:56:59Z
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.

Michael Paquier wrote:

> Then, let's consider the beginning of the first commit fest of v12 as
> judgement.  Implementing radix tree for shared buffers is a long-term
> project, which has no guarantee to get merged, while a visibly-simple
> reloptions which helps in some cases...

In the scenario we studied, the truncations were causing periodic
hiccups which were quite severe.  The truncations were completely
useless anyway because the table grew back to the original size daily (a
few dozen GBs I think).  That was a lot of unnecessary work, and under
exclusive lock no less.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
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