Обсуждение: vacuum messges

What do these mean?

NOTICE:  FlushRelationBuffers(message, 2): block 2 is referenced
(private 0,
global 1)
FATAL 1:  VACUUM (vc_repair_frag): FlushRelationBuffers returned -2
pqReadData() -- backend closed the channel unexpectedly.
        This probably means the backend terminated abnormally
        before or while processing the request.
connection to server was lost
vacuumdb: vacuum failed


NOTICE:  FlushRelationBuffers(message, 2): block 2 is referenced
(private 0,
global 1)
FATAL 1:  VACUUM (vc_vacheap): FlushRelationBuffers returned -2
pqReadData() -- backend closed the channel unexpectedly.
        This probably means the backend terminated abnormally
        before or while processing the request.
connection to server was lost
vacuumdb: vacuum failed

Joseph Shraibman <jks@selectacast.net> writes:
> What do these mean?
> NOTICE:  FlushRelationBuffers(message, 2): block 2 is referenced
> (private 0,
> global 1)
> FATAL 1:  VACUUM (vc_repair_frag): FlushRelationBuffers returned -2

We've seen a couple reports of this happening with 7.0.  Apparently
there is a buffer-reference-count leak happening somewhere, such that
a disk buffer is still marked as busy even though (presumably) nothing
but VACUUM is actually touching the table.  When VACUUM sees this, it
punts for fear of creating problems.

You can recover by restarting the postmaster, but the really interesting
question is how the system gets into this state in the first place.
If you can work out a reproducible or semi-reproducible sequence for
causing the problem to occur, please tell us!

            regards, tom lane