Horton

Re: Bugs in TOAST handling, OID assignment and redo recovery

Peter Eisentraut <peter.eisentraut@2ndquadrant.com>

View thread View on postgr.es
From: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
To: Pavan Deolasee <pavan.deolasee@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2018-04-12T00:23:31Z
Lists: pgsql-hackers

Attachments

On 4/10/18 06:29, Pavan Deolasee wrote:
> One of our 2ndQuadrant support customers recently reported a sudden rush
> of TOAST errors post a crash recovery, nearly causing an outage. Most
> errors read like this:
> 
> ERROR: unexpected chunk number 0 (expected 1) for toast value nnnn

While researching this, I found that the terminology in this code is
quite inconsistent.  It talks about chunks ids, chunk indexes, chunk
numbers, etc. seemingly interchangeably.  The above error is actually
about the chunk_seq, not about the chunk_id, as one might think.

The attached patch is my attempt to clean this up a bit.  Thoughts?

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Commits

  1. Ignore nextOid when replaying an ONLINE checkpoint.

  2. Do not select new object OIDs that match recently-dead entries.