Alvaro Herrera <[EMAIL PROTECTED]> writes: > I think the problem is that CreateMultiXactId calls > GetNewMultiXactId and then RecordNewMultiXact, and the lock is released > between the calls. So one backend could try to read the offset before > another one had the time to finish writing it.
Ugh, yes, that is clearly a hole :-( even if it turns out not to explain Matteo's observation. I don't see any easy way to fix this except by introducing a lot more locking than is there now --- ie, holding the MultiXactGenLock until the new mxact's starting offset has been written to disk. Any better ideas? regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match