Re: VACUUM warning/error (?)

Nicolas Kowalski <Nicolas(dot)Kowalski(at)imag(dot)fr> writes:
> NOTICE: FlushRelationBuffers(trace_sql, 162): block 239 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

> All seems to work, in particular this 'trace_sql' table, but what does
> mean this error message ?

It's complaining about a buffer reference count leakage --- most likely
due to the bug in 7.0.* whereby a backend may fail to run transaction-
abort code before shutting down, if the client disconnects in the middle
of a transaction block.

You could get rid of the immediate problem by restarting the postmaster,
but I recommend updating to 7.0.3 to fix the real bug.

regards, tom lane