Re: 8.1 index corruption woes - Mailing list pgsql-hackers

From Alvaro Herrera
Subject Re: 8.1 index corruption woes
Date
Msg-id 20080708021820.GH4681@alvh.no-ip.org
Whole thread Raw
In response to Re: 8.1 index corruption woes  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Tom Lane wrote:
> Alvaro Herrera <alvherre@commandprompt.com> writes:
> > Tom Lane wrote:
> >> Another point to keep in mind, if you are trying to analyze files
> >> belonging to a live database, is that what you can see in the filesystem
> >> may not be the "current" contents of every page.  For typical access
> >> patterns it'd be unsurprising for the visible index pages to lag behind
> >> those of the heap, since they'd be "hotter" and tend to stay in shared
> >> buffers longer.
> 
> > Hmm, I think the files come from a PITR slave that's not online.  I'll
> > ask to be sure.
> 
> 8.1 didn't have restartpoint code, and of course bgwriter isn't running;
> so I believe filesystem pages on a PITR slave could be arbitrarily far
> out of date if the corresponding shared buffer got touched regularly.
> Try doing the analysis on the master immediately after a CHECKPOINT
> command.

Okay.

I'll also check out tomorrow the LSN on the involved pages to see if
there's anything obviously bogus.

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support


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