On Thu, Jun 27, 2019 at 2:34 PM Tom Lane <t...@sss.pgh.pa.us> wrote: > Ben Snaidero <bensnaid...@geotab.com> writes: > > I am running into a strange issue with Postgres 10 when using pg_dump > with > > the directory format and jobs parameter set it intermittently hangs. > Seems > > to occur less frequently the lower I set the jobs parameter but does > happen > > eventually even when set to 2 (could not reproduce when jobs=1). I've > > tested with Postgres 11 and no matter how high I set the jobs parameter > it > > never hangs (tested all the way up to jobs=8). Also with Postgres 10 and > > other formats I don't run into the issue. Here are my server specs and > > software versions (OS and Postgres) > > FWIW, it looks like the hang is on the client side (i.e., pg_dump itself). > The one active server process is just trying to send COPY data and is > waiting for the client to take it. So I'm wondering about deadlocks > inside parallel pg_dump. > > This doesn't present any obvious answer, because there is not much > difference between the parallel pg_dump logic in 10 and 11. But > maybe you could get stack trace(s) out of the stuck pg_dump job on 10? > (Keep in mind that unlike the backend, the pg_dump process will have > multiple threads in this situation.) > > Another thing you could do to triangulate is to verify that v11 pg_dump > is okay working against the v10 server. Unfortunately the other > combination can't be tested, but this'd be enough to exonerate the v10 > server side. > > regards, tom lane >
Thanks for the suggestion Tom. I've verified that this looks to be a v10 server side issue as using the Postgres11 pg_dump.exe against the v10 server I still encounter the same hanging issue. Here are the stack traces from each of the threads of the pg_dump.exe. ntoskrnl.exe!KiSwapContext+0x76 ntoskrnl.exe!KiSwapThread+0x17d ntoskrnl.exe!KiCommitThreadWait+0x14f ntoskrnl.exe!KeWaitForSingleObject+0x377 ntoskrnl.exe!KiSchedulerApc+0x231 ntoskrnl.exe!KiDeliverApc+0x22a ntoskrnl.exe!KiSwapThread+0x364 ntoskrnl.exe!KiCommitThreadWait+0x14f ntoskrnl.exe!KeWaitForSingleObject+0x377 ntoskrnl.exe!NtWaitForSingleObject+0xf8 ntoskrnl.exe!KiSystemServiceCopyEnd+0x13 ntdll.dll!NtWaitForSingleObject+0x14 mswsock.dll!SockWaitForSingleObject+0x133 mswsock.dll!WSPSelect+0x7e4 WS2_32.dll!select+0x1d3 pg_dump.exe+0x64ae pg_dump.exe+0x65bd pg_dump.exe+0x6228 pg_dump.exe+0x509f pg_dump.exe+0x980b pg_dump.exe+0x117cc pg_dump.exe+0x6f3f pg_dump.exe+0x30c22 pg_dump.exe+0x3cb77 KERNEL32.DLL!BaseThreadInitThunk+0x14 ntdll.dll!RtlUserThreadStart+0x21 ---------------------------------------------------------------------- ntoskrnl.exe!KiSwapContext+0x76 ntoskrnl.exe!KiSwapThread+0x17d ntoskrnl.exe!KiCommitThreadWait+0x14f ntoskrnl.exe!KeWaitForSingleObject+0x377 ntoskrnl.exe!KiSchedulerApc+0x231 ntoskrnl.exe!KiDeliverApc+0x22a ntoskrnl.exe!KiSwapThread+0x364 ntoskrnl.exe!KiCommitThreadWait+0x14f ntoskrnl.exe!KeWaitForSingleObject+0x377 ntoskrnl.exe!NtWaitForSingleObject+0xf8 ntoskrnl.exe!KiSystemServiceCopyEnd+0x13 ntdll.dll!NtWaitForSingleObject+0x14 mswsock.dll!SockWaitForSingleObject+0x133 mswsock.dll!WSPRecv+0x5d2 WS2_32.dll!recv+0x16c pg_dump.exe+0x6746 pg_dump.exe+0x61ab pg_dump.exe+0x5e57 pg_dump.exe+0x6a22 MSVCR120.dll!_callthreadstartex+0x17 MSVCR120.dll!_threadstartex+0x88 KERNEL32.DLL!BaseThreadInitThunk+0x14 ntdll.dll!RtlUserThreadStart+0x21 ---------------------------------------------------------------------- ntoskrnl.exe!KiSwapContext+0x76 ntoskrnl.exe!KiSwapThread+0x17d ntoskrnl.exe!KiCommitThreadWait+0x14f ntoskrnl.exe!KeWaitForSingleObject+0x377 ntoskrnl.exe!KiSchedulerApc+0x231 ntoskrnl.exe!KiDeliverApc+0x22a ntoskrnl.exe!KiSwapThread+0x364 ntoskrnl.exe!KiCommitThreadWait+0x14f ntoskrnl.exe!KeWaitForSingleObject+0x377 ntoskrnl.exe!NtWaitForSingleObject+0xf8 ntoskrnl.exe!KiSystemServiceCopyEnd+0x13 ntdll.dll!NtWaitForSingleObject+0x14 mswsock.dll!SockWaitForSingleObject+0x133 mswsock.dll!WSPRecv+0x5d2 WS2_32.dll!recv+0x16c pg_dump.exe+0x6746 pg_dump.exe+0x61ab pg_dump.exe+0x5e57 pg_dump.exe+0x6a22 MSVCR120.dll!_callthreadstartex+0x17 MSVCR120.dll!_threadstartex+0x88 KERNEL32.DLL!BaseThreadInitThunk+0x14 ntdll.dll!RtlUserThreadStart+0x21 ---------------------------------------------------------------------- ntoskrnl.exe!KiSwapContext+0x76 ntoskrnl.exe!KiSwapThread+0x17d ntoskrnl.exe!KiCommitThreadWait+0x14f ntoskrnl.exe!KeWaitForSingleObject+0x377 ntoskrnl.exe!KiSchedulerApc+0x231 ntoskrnl.exe!KiDeliverApc+0x22a ntoskrnl.exe!KiSwapThread+0x364 ntoskrnl.exe!KiCommitThreadWait+0x14f ntoskrnl.exe!KeWaitForSingleObject+0x377 ntoskrnl.exe!NtWaitForSingleObject+0xf8 ntoskrnl.exe!KiSystemServiceCopyEnd+0x13 ntdll.dll!NtWaitForSingleObject+0x14 mswsock.dll!SockWaitForSingleObject+0x133 mswsock.dll!WSPSelect+0x7e4 WS2_32.dll!select+0x1d3 LIBPQ.dll!PQenv2encoding+0x1301 LIBPQ.dll!PQenv2encoding+0x11a3 LIBPQ.dll!PQenv2encoding+0xc7a LIBPQ.dll!PQprintTuples+0x34b0 pg_dump.exe+0x313df pg_dump.exe+0x98a0 pg_dump.exe+0x11e89 pg_dump.exe+0x6100 pg_dump.exe+0x5e57 pg_dump.exe+0x6a22 MSVCR120.dll!_callthreadstartex+0x17 MSVCR120.dll!_threadstartex+0x88 KERNEL32.DLL!BaseThreadInitThunk+0x14 ntdll.dll!RtlUserThreadStart+0x21 ---------------------------------------------------------------------- ntoskrnl.exe!KiSwapContext+0x76 ntoskrnl.exe!KiSwapThread+0x17d ntoskrnl.exe!KiCommitThreadWait+0x14f ntoskrnl.exe!KeWaitForSingleObject+0x377 ntoskrnl.exe!KiSchedulerApc+0x231 ntoskrnl.exe!KiDeliverApc+0x22a ntoskrnl.exe!KiSwapThread+0x364 ntoskrnl.exe!KiCommitThreadWait+0x14f ntoskrnl.exe!KeWaitForSingleObject+0x377 ntoskrnl.exe!NtWaitForSingleObject+0xf8 ntoskrnl.exe!KiSystemServiceCopyEnd+0x13 ntdll.dll!NtWaitForSingleObject+0x14 mswsock.dll!SockWaitForSingleObject+0x133 mswsock.dll!WSPRecv+0x5d2 WS2_32.dll!recv+0x16c pg_dump.exe+0x6746 pg_dump.exe+0x61ab pg_dump.exe+0x5e57 pg_dump.exe+0x6a22 MSVCR120.dll!_callthreadstartex+0x17 MSVCR120.dll!_threadstartex+0x88 KERNEL32.DLL!BaseThreadInitThunk+0x14 ntdll.dll!RtlUserThreadStart+0x21 Do these stack traces shed help at all?
