Re: COPY FROM STDIN hang

> On Mar 23, 2021, at 3:16 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
> Robert Creager <robert(at)logicalchaos(dot)org> writes:
>> We’re getting occasional hangs when using COPY FROM STDIN.
>
> You mean the backend hangs? Can you get a stack trace from that?

The entire backend doesn’t hang, we’re able to process queries on other connections. It’s just the COPY FROM thread that’s hung.

>
> https://wiki.postgresql.org/wiki/Generating_a_stack_trace_of_a_PostgreSQL_backend

(gdb) cont
Continuing.
^C
Program received signal SIGINT, Interrupt.
0x00000000006a0d5b in UnpinBuffer ()
(gdb) bt
#0 0x00000000006a0d5b in UnpinBuffer ()
#1 0x00000000006a0abe in ReleaseAndReadBuffer ()
#2 0x00000000004a9c00 in _bt_relandgetbuf ()
#3 0x00000000004acbc6 in _bt_moveright ()
#4 0x00000000004aca0a in _bt_search ()
#5 0x00000000004a6a6e in _bt_doinsert ()
#6 0x00000000004abac6 in btinsert ()
#7 0x00000000005b52b0 in ExecInsertIndexTuples ()
#8 0x0000000000561de0 in CopyFromInsertBatch ()
#9 0x000000000055c3cd in DoCopy ()
#10 0x00000000006d46f1 in standard_ProcessUtility ()
#11 0x00000000006d3c69 in PortalRunUtility ()
#12 0x00000000006d3346 in PortalRunMulti ()
#13 0x00000000006d2d59 in PortalRun ()
#14 0x00000000006d11c8 in PostgresMain ()
#15 0x000000000066b224 in BackendRun ()
#16 0x000000000066a8e6 in ServerLoop ()
#17 0x00000000006679c0 in PostmasterMain ()
#18 0x00000000005f4da7 in main ()
(gdb) cont
Continuing.
^C
Program received signal SIGINT, Interrupt.
0x00000000006c2c88 in LWLockRelease ()
(gdb) bt
#0 0x00000000006c2c88 in LWLockRelease ()
#1 0x000000000069fd3c in ReadBuffer_common ()
#2 0x000000000069fb6c in ReadBufferExtended ()
#3 0x00000000004a9c00 in _bt_relandgetbuf ()
#4 0x00000000004acbc6 in _bt_moveright ()
#5 0x00000000004aca0a in _bt_search ()
#6 0x00000000004a6a6e in _bt_doinsert ()
#7 0x00000000004abac6 in btinsert ()
#8 0x00000000005b52b0 in ExecInsertIndexTuples ()
#9 0x0000000000561de0 in CopyFromInsertBatch ()
#10 0x000000000055c3cd in DoCopy ()
#11 0x00000000006d46f1 in standard_ProcessUtility ()
#12 0x00000000006d3c69 in PortalRunUtility ()
#13 0x00000000006d3346 in PortalRunMulti ()
#14 0x00000000006d2d59 in PortalRun ()
#15 0x00000000006d11c8 in PostgresMain ()
#16 0x000000000066b224 in BackendRun ()
#17 0x000000000066a8e6 in ServerLoop ()
#18 0x00000000006679c0 in PostmasterMain ()
#19 0x00000000005f4da7 in main ()
(gdb) cont
Continuing.
^C
Program received signal SIGINT, Interrupt.
0x00000000004accba in _bt_moveright ()
(gdb) bt
#0 0x00000000004accba in _bt_moveright ()
#1 0x00000000004aca0a in _bt_search ()
#2 0x00000000004a6a6e in _bt_doinsert ()
#3 0x00000000004abac6 in btinsert ()
#4 0x00000000005b52b0 in ExecInsertIndexTuples ()
#5 0x0000000000561de0 in CopyFromInsertBatch ()
#6 0x000000000055c3cd in DoCopy ()
#7 0x00000000006d46f1 in standard_ProcessUtility ()
#8 0x00000000006d3c69 in PortalRunUtility ()
#9 0x00000000006d3346 in PortalRunMulti ()
#10 0x00000000006d2d59 in PortalRun ()
#11 0x00000000006d11c8 in PostgresMain ()
#12 0x000000000066b224 in BackendRun ()
#13 0x000000000066a8e6 in ServerLoop ()
#14 0x00000000006679c0 in PostmasterMain ()
#15 0x00000000005f4da7 in main ()
(gdb) detach