Kris Kennaway <[EMAIL PROTECTED]> writes: > I have not studied the exact code path, but there are indeed multiple > wakeups happening from the semaphore code (as many as the number of > active postgresql processes). It is easy to instrument > sleepq_broadcast() and log them when they happen.
There are certainly cases where Postgres will wake up a number of processes in quick succession, but that should happen from a separate semop() kernel call, on a different semaphore, for each such process. If there's really multiple processes being released by the same semop() then there's a bug we need to look into (or maybe it's a kernel bug?). Anyway I'd be interested to know what the test case is, and which PG version you were testing. 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