Re: The lightbulb just went on...

Michael J Schout <mschout(at)gkg(dot)net> writes:
> ERROR: RelationClearRelation: relation 1668325 modified while in use
> relation 1668325 is a view named "sessions".

Hm. This message is coming out of the relation cache code when it sees
an invalidate-your-cache-for-this-relation message from another backend
and the relation in question has already been locked during the current
transaction. Probably, what is happening is that the vacuum process is
vacuuming the view (not too much to do there ;-) but it does it anyway)
and sending out the cache inval message for it after the other client
process has already started parsing of a query using the view.

This is a fairly subtle problem that I don't think we will be able to
fix as a backpatch for 7.0.*. It's on the to-fix list for 7.1 though.

regards, tom lane