Re: [HACKERS] Block level parallel vacuum

On Fri, 20 Dec 2019 at 17:17, Prabhat Sahu
<prabhat(dot)sahu(at)enterprisedb(dot)com> wrote:
>
> Hi,
>
> While testing this feature with parallel vacuum on "TEMPORARY TABLE", I got a server crash on PG Head+V36_patch.
> Changed configuration parameters and Stack trace are as below:
>
> autovacuum = on
> max_worker_processes = 4
> shared_buffers = 10MB
> max_parallel_workers = 8
> max_parallel_maintenance_workers = 8
> vacuum_cost_limit = 2000
> vacuum_cost_delay = 10
> min_parallel_table_scan_size = 8MB
> min_parallel_index_scan_size = 0
>
> -- Stack trace:
> [centos(at)parallel-vacuum-testing bin]$ gdb -q -c data/core.1399 postgres
> Reading symbols from /home/centos/BLP_Vacuum/postgresql/inst/bin/postgres...done.
> [New LWP 1399]
> [Thread debugging using libthread_db enabled]
> Using host libthread_db library "/lib64/libthread_db.so.1".
> Core was generated by `postgres: autovacuum worker postgres '.
> Program terminated with signal 6, Aborted.
> #0 0x00007f4517d80337 in raise () from /lib64/libc.so.6
> Missing separate debuginfos, use: debuginfo-install glibc-2.17-292.el7.x86_64 keyutils-libs-1.5.8-3.el7.x86_64 krb5-libs-1.15.1-37.el7_7.2.x86_64 libcom_err-1.42.9-16.el7.x86_64 libgcc-4.8.5-39.el7.x86_64 libselinux-2.5-14.1.el7.x86_64 openssl-libs-1.0.2k-19.el7.x86_64 pcre-8.32-17.el7.x86_64 zlib-1.2.7-18.el7.x86_64
> (gdb) bt
> #0 0x00007f4517d80337 in raise () from /lib64/libc.so.6
> #1 0x00007f4517d81a28 in abort () from /lib64/libc.so.6
> #2 0x0000000000a96341 in ExceptionalCondition (conditionName=0xd18efb "strvalue != NULL", errorType=0xd18eeb "FailedAssertion",
> fileName=0xd18ee0 "snprintf.c", lineNumber=442) at assert.c:67
> #3 0x0000000000b02522 in dopr (target=0x7ffdb0e38450, format=0xc5fa95 ".%s\"", args=0x7ffdb0e38538) at snprintf.c:442
> #4 0x0000000000b01ea6 in pg_vsnprintf (str=0x256df50 "autovacuum: dropping orphan temp table \"postgres.", '\177' <repeats 151 times>..., count=1024,
> fmt=0xc5fa68 "autovacuum: dropping orphan temp table \"%s.%s.%s\"", args=0x7ffdb0e38538) at snprintf.c:195
> #5 0x0000000000afbadf in pvsnprintf (buf=0x256df50 "autovacuum: dropping orphan temp table \"postgres.", '\177' <repeats 151 times>..., len=1024,
> fmt=0xc5fa68 "autovacuum: dropping orphan temp table \"%s.%s.%s\"", args=0x7ffdb0e38538) at psprintf.c:110
> #6 0x0000000000afd34b in appendStringInfoVA (str=0x7ffdb0e38550, fmt=0xc5fa68 "autovacuum: dropping orphan temp table \"%s.%s.%s\"", args=0x7ffdb0e38538)
> at stringinfo.c:149
> #7 0x0000000000a970fd in errmsg (fmt=0xc5fa68 "autovacuum: dropping orphan temp table \"%s.%s.%s\"") at elog.c:832
> #8 0x00000000008588d2 in do_autovacuum () at autovacuum.c:2249
> #9 0x0000000000857b29 in AutoVacWorkerMain (argc=0, argv=0x0) at autovacuum.c:1689
> #10 0x000000000085772f in StartAutoVacWorker () at autovacuum.c:1483
> #11 0x000000000086e64f in StartAutovacuumWorker () at postmaster.c:5562
> #12 0x000000000086e106 in sigusr1_handler (postgres_signal_arg=10) at postmaster.c:5279
> #13 <signal handler called>
> #14 0x00007f4517e3f933 in __select_nocancel () from /lib64/libc.so.6
> #15 0x0000000000869838 in ServerLoop () at postmaster.c:1691
> #16 0x0000000000869212 in PostmasterMain (argc=3, argv=0x256bd70) at postmaster.c:1400
> #17 0x000000000077855d in main (argc=3, argv=0x256bd70) at main.c:210
> (gdb)
>
> I have tried to reproduce the same with all previously executed queries but now I am not able to reproduce the same.

Thanks Prabhat for reporting this issue.

I am able to reproduce this issue at my end. I tested and verified
that this issue is not related to parallel vacuum patch. I am able to
reproduce this issue on HEAD without parallel vacuum patch(v37).

I will report this issue in new thread with reproducible test case.

Thanks and Regards
Mahendra Thalor
EnterpriseDB: http://www.enterprisedb.com