Hi Here is an updated patch, following the discussion. The patch can be found at: http://soc.phlo.org/lazyxidassign.v4.patch (I seems I still can't get attachments through to this list)
Most changes are just small fixes and tweaks. Those are .) Introduced %v for log_line_prefix .) I missed a few places when I renamed ResourceOwnerId to VirtualTransactionId. (In lock.c/.h and lmgr.c/.h + a few comments). Should be fixed now. .) Fixed some typos and outdated-ness in comments. Two changes are a bit larger 1) 2PC was broken in V3. I added code that skips LOCKTYPE_VIRTUALTRANSACTION locks when writing the locks to the 2PC state file, but I didn't add the same exception to the code that reassigns the locks to a dummy PGROC afterwards. So the locks weren't released at PREPARE time. Fixed now. 2) The more I thought about the sessionId, the less I liked it. It adds a new per-backend identifier, beside pid and BackendId, only to than *still* have wraparound issues. That seems a bit stupid. I therefore got rid of the sessionId completely, and replaced it with MyBackendId. To guarantee that VirtualTransactionIds are not reused too quickly, I added an array nextLocalTransactionIds to shared memory, with one entry per backendId. That seems much cleaner - it doesn't add yet another per-backend identifier, doesn't need yet another variable initialized at backend start, and solved the wraparound problem too. It *does* cost a bit of shared memory, but not much. For max_backends=2048 the array is as large as *one* shared buffer. It doesn't need any locking, either, because each backend only ever touches it's own entry in the array. Because the backendId part of VirtualTransactionIds is now always a rather small number (<= MaxBackends), and might be interesting to know, I changed the string representation to show the backendId in decimal notation. greetings, Florian Pflug ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster
