On 04/26/2011 04:28 PM, Tom Lane wrote:
Andrew Dunstan<and...@dunslane.net> writes:This has happened again. This time we have some debug info available, and can possible get more, if people tell me what will be helpful: (gdb) f 2 #2 0x00000000005de735 in LockBufferForCleanup (buffer=310163) at bufmgr.c:2432 2432 ProcWaitForSignal(); (gdb) p *bufHdr $2 = {tag = {rnode = {spcNode = 16393, dbNode = 40475, relNode = 41880}, forkNum = MAIN_FORKNUM, blockNum = 18913}, flags = 6, usage_count = 1, refcount = 1, wait_backend_pid = 9111, buf_hdr_lock = 0 '\000', buf_id = 310162, freeNext = -2, io_in_progress_lock = 620448, content_lock = 620449}Well, that's pretty interesting: refcount is only 1, and the BM_PIN_COUNT_WAITER flag is not set.
I noticed that.
AFAICS this *must* mean that the buffer had been pinned and whoever had it (presumably bgwriter) did UnpinBuffer(). So it appears that the signal just plain got lost :-(, which suggests a kernel bug. What platform is this on, again?
CentOS 5.5, x86_64, kernel 2.6.18-194.32.1.el5 cheers andrew -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
