Re: B-tree page deletion boundary cases

On Sun, Apr 22, 2012 at 12:13:34AM +0530, Nikhil Sontakke wrote:
> Was wondering if there's a similar bug which gets triggered while using
> VACUUM FULL. See for instance this thread:
> 
> http://postgresql.1045698.n5.nabble.com/index-corruption-in-PG-8-3-13-td4257589.html
> 
> This issue has been reported on-off from time to time and in most cases
> VACUUM or VACUUM FULL appears to be involved. We have usually attributed it
> to hardware issues and reindex has been recommended by default as a
> solution/work around..

I do not perceive much similarity.  The bug I've raised can produce wrong
query results transiently.  It might permit injecting a tuple into the wrong
spot in the tree, yielding persistent wrong results.  It would not introduce
tree-structural anomalies like sibling pointers directed at zeroed pages or
internal pages in an 1-level tree.  Given the symptoms you reported, I share
Robert's suspicion of WAL replay in your scenario.