Horton

Re: Hot Backup with rsync fails at pg_clog if under load

Florian G. Pflug <fgp@phlo.org>

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From: Florian Pflug <fgp@phlo.org>
To: Simon Riggs <simon@2ndQuadrant.com>
Cc: Chris Redekop <chris@replicon.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2011-10-24T06:05:01Z
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. Derive oldestActiveXid at correct time for Hot Standby.

  2. Start Hot Standby faster when initial snapshot is incomplete.

  3. Fix timing of Startup CLOG and MultiXact during Hot Standby

On Oct24, 2011, at 01:27 , Simon Riggs wrote:
> FATAL:  could not access status of transaction 21110784
> which, in pg_subtrans, is the first xid on a new subtrans page. So we
> have missed zeroing a page.
> 
> pg_control shows ... Latest checkpoint's oldestActiveXID:  21116666
> which shows quite clearly that the pg_control file is later than it should be.

But shouldn't pg_control be largely irrelevant in a hot backup scenario? Most
(all?) of the information contained therein should be overwritten with the
contents of the checkpoint referenced by the backup label, shouldn't it?

best regards,
Florian Pflug