Sorry in advance for link-breaking message force by gmail.. https://www.postgresql.org/message-id/flat/cy4pr2101mb0804ce9836e582c0702214e8aa...@cy4pr2101mb0804.namprd21.prod.outlook.com
I assume that we are in a consensus about the problem we are to fix here. > 0a 00000004`8080cc30 00000004`80dcf917 postgres!PGSemaphoreLock+0x65 > [d:\orcasqlagsea10\14\s\src\backend\port\win32_sema.c @ 158] > 0b 00000004`8080cc90 00000004`80db025c postgres!LWLockAcquire+0x137 > [d:\orcasqlagsea10\14\s\src\backend\storage\lmgr\lwlock.c @ 1234] > 0c 00000004`8080ccd0 00000004`80db25db postgres!AbortBufferIO+0x2c > [d:\orcasqlagsea10\14\s\src\backend\storage\buffer\bufmgr.c @ 3995] > 0d 00000004`8080cd20 00000004`80dbce36 postgres!AtProcExit_Buffers+0xb > [d:\orcasqlagsea10\14\s\src\backend\storage\buffer\bufmgr.c @ 2479] > 0e 00000004`8080cd50 00000004`80dbd1bd postgres!shmem_exit+0xf6 > [d:\orcasqlagsea10\14\s\src\backend\storage\ipc\ipc.c @ 262] > 0f 00000004`8080cd80 00000004`80dbccfd postgres!proc_exit_prepare+0x4d > [d:\orcasqlagsea10\14\s\src\backend\storage\ipc\ipc.c @ 188] > 10 00000004`8080cdb0 00000004`80ef9e74 postgres!proc_exit+0xd > [d:\orcasqlagsea10\14\s\src\backend\storage\ipc\ipc.c @ 141] > 11 00000004`8080cde0 00000004`80ddb6ef postgres!errfinish+0x204 > [d:\orcasqlagsea10\14\s\src\backend\utils\error\elog.c @ 624] > 12 00000004`8080ce50 00000004`80db0f59 postgres!mdread+0x12f > [d:\orcasqlagsea10\14\s\src\backend\storage\smgr\md.c @ 806] Ok, we are fixing this. The proposed patch lets LWLockReleaseAll() called before InitBufferPoolBackend() by registering the former after the latter into on_shmem_exit list. Even if it works, I think it's neither clean nor safe to register multiple order-sensitive callbacks. AtProcExit_Buffers has the following comment: > * During backend exit, ensure that we released all shared-buffer locks and > * assert that we have no remaining pins. And the only caller of it is shmem_exit. More of that, all other caller sites calls LWLockReleaseAll() just before calling it. If that's the case, why don't we just release all LWLocks in shmem_exit or in AtProcExit_Buffers before calling AbortBufferIO()? I think it's sufficient that AtProcExit_Buffers calls it at the beginning. (The comment for the funcgtion needs editing). regards. -- Kyotaro Horiguchi NTT Open Source Software Center
