Re: pg_dump crashes

On 5/22/20 6:40 AM, Nico De Ranter wrote:
> I was just trying that.  It's always the same (huge) table that crashes
> the pg_dump.   Running a dump excluding that one table goes fine,
> running a dump of only that one table crashes.
> In the system logs I always see a segfault
>
> May 22 15:22:14 core4 kernel: [337837.874618] postgres[1311]: segfault
> at 7f778008ed0d ip 000055f197ccc008 sp 00007ffdd1fc15a8 error 4 in
> postgres[55f1977c0000+727000]
>
> It doesn't seem to be an Out-of-memory thing (at least not on the OS level).
> The database is currently installed on a dedicated server with 32GB
> RAM.   I tried tweaking some of the memory parameters for postgres, but
> the crash always happens at the exact same spot (if I run pg_dump for
> that one table with and without memory tweaks the resulting files are
> identical).
>
> One thing I just noticed looking at the dump file: at around the end of
> the file I see this:

So the below is the output from?:

pg_dumpall --cluster 11/main --file=dump.sql

>
> 2087983804 516130 37989 2218636 3079067 0 0 P4B BcISC IGk L BOT BOP A jC
> BAA I BeMj/b BceUl6 BehUAn 0Ms A C I4p9CBfUiSeAPU4eDuipKQ
> *4557430888798830399 1061109567 1061109567 1061109567 1061109567 16191
> \N \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1061109567 1061109567 16191 \N
> \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1061109567 1061109567 16191 \N
> \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1145127487 1413694803 21071 \N
> \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1061109567 1061109567 16191 \N
> \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1061109567 1061109567 16191 \N
> \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1061109567 1061109567 16191 \N
> \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1061109567 1061109567 16191 \N
> \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1061109567 1061109567 16191 \N
> \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1061109567 1061109567 16191 \N
> \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1145127487 1413694803 21071 \N
> \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1061109567 1061109567 16191 \N
> \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1061109567 1061109567 16191 \N
> \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1061109567 1061109567 16191 \N
> \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1061109567 1061109567 16191 \N
> \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1061109567 1061109567 16191 \N
> \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1061109567 1061109567 16191 \N
> \N ??????????????????????????????
> 6071772946555290175 1056985679 1061109567 1061109567 1061109567 16191 \N
> \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1061109567 1061109567 16191 \N
> \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1061109567 1061109567 16191 \N
> \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1061109567 1061109567 16191 \N
> \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1061109567 1061109567 16191 \N
> \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1061109567 1061109567 16191 \N
> \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1061109567 1061109567 16191 \N
> \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1061109567 1061109567 16191 \N
> \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1061109567 1061109567 16191 \N
> \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1061109567 1061109567 16191 \N
> \N ??????????????????????????????
> 4557430888798830399 1061109567 1061109567 1061109567 1061109567 16191 \N
> \N ??????????????????????????????*
> 2087983833 554418 37989 5405605 14507502 0 0 P4B Bb8c/ IGk L BOS BOP A
> Lfh BAA Bg BeMj+2 Bd1LVN BehUAl rlx ABA TOR
>
> It looks suspicious however there are about 837 more lines before the
> output stops.
>
> Nico
>
> On Fri, May 22, 2020 at 3:27 PM Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com
> <mailto:adrian(dot)klaver(at)aklaver(dot)com>> wrote:
>
> On 5/22/20 5:37 AM, Nico De Ranter wrote:
> > Hi all,
> >
> > Postgres version: 9.5
> > OS: Ubuntu 18.04.4
> >
> > I have a 144GB Bacula database that crashes the postgres daemon
> when I
> > try to do a pg_dump.
> > At some point the server ran out of diskspace for the database
> storage.
> > I expanded the lvm and rebooted the server. It seemed to work fine,
> > however when I try to dump the bacula database the postgres
> daemon dies
> > after about 37GB.
> >
> > I tried copying the database to another machine and upgrading
> postgres
> > to 11 using pg_upgrade.  The upgrade seems to work but I still get
> > exactly the same problem when trying to dump the database.
> >
> > postgres(at)core4:~$ pg_dumpall --cluster 11/main --file=dump.sql
> > pg_dump: Dumping the contents of table "file" failed:
> PQgetCopyData()
> > failed.
> > pg_dump: Error message from server: server closed the connection
> > unexpectedly
> > This probably means the server terminated abnormally
> > before or while processing the request.
> > pg_dump: The command was: COPY public.file (fileid, fileindex,
> jobid,
> > pathid, filenameid, deltaseq, markid, lstat, md5) TO stdout;
> > pg_dumpall: pg_dump failed on database "bacula", exiting
>
> What happens if you try to dump just this table?
>
> Something along lines of:
>
> pg_dump -t file -d some_db -U some_user
>
> Have you looked at the system logs to see if it is the OS killing the
> process?
>
>
> >
> > In the logs I see:
> >
> > 2020-05-22 14:23:30.649 CEST [12768] LOG:  server process (PID
> 534) was
> > terminated by signal 11: Segmentation fault
> > 2020-05-22 14:23:30.649 CEST [12768] DETAIL:  Failed process was
> > running: COPY public.file (fileid, fileindex, jobid, pathid,
> filenameid,
> > deltaseq, markid, lstat, md5) TO stdout;
> > 2020-05-22 14:23:30.651 CEST [12768] LOG:  terminating any other
> active
> > server processes
> > 2020-05-22 14:23:30.651 CEST [482] WARNING:  terminating connection
> > because of crash of another server process
> > 2020-05-22 14:23:30.651 CEST [482] DETAIL:  The postmaster has
> commanded
> > this server process to roll back the current transaction and exit,
> > because another server process exited abnormally and possibly
> corrupted
> > shared memory.
> > 2020-05-22 14:23:30.651 CEST [482] HINT:  In a moment you should
> be able
> > to reconnect to the database and repeat your command.
> > 2020-05-22 14:23:30.652 CEST [12768] LOG:  all server processes
> > terminated; reinitializing
> > 2020-05-22 14:23:30.671 CEST [578] LOG:  database system was
> > interrupted; last known up at 2020-05-22 14:15:19 CEST
> > 2020-05-22 14:23:30.809 CEST [578] LOG:  database system was not
> > properly shut down; automatic recovery in progress
> > 2020-05-22 14:23:30.819 CEST [578] LOG:  redo starts at 197/D605EA18
> > 2020-05-22 14:23:30.819 CEST [578] LOG:  invalid record length at
> > 197/D605EA50: wanted 24, got 0
> > 2020-05-22 14:23:30.819 CEST [578] LOG:  redo done at 197/D605EA18
> > 2020-05-22 14:23:30.876 CEST [12768] LOG:  database system is
> ready to
> > accept connections
> > 2020-05-22 14:29:07.511 CEST [12768] LOG:  received fast shutdown
> request
> >
> >
> > Any ideas how to fix or debug this?
> >
> > Nico
> >
> > --
> >
> > Nico De Ranter
> >
> > Operations Engineer
> >
> > T. +32 16 38 72 10
> >
> >
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> >
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> >
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> --
> Adrian Klaver
> adrian(dot)klaver(at)aklaver(dot)com <mailto:adrian(dot)klaver(at)aklaver(dot)com>
>
>
>
> --
>
> Nico De Ranter
>
> Operations Engineer
>
> T. +32 16 38 72 10
>
>
> <http://www.esaturnus.com>
>
> <http://www.esaturnus.com>
>
>
> eSATURNUS
> Philipssite 5, D, box 28
> 3001 Leuven – Belgium
>
>
>
> T. +32 16 40 12 82
> F. +32 16 40 84 77
> www.esaturnus.com <http://www.esaturnus.com>
>
> ** <http://www.esaturnus.com/>
>
> *For Service & Support :*
>
> Support Line Belgium: +32 2 2009897
>
> Support Line International: +44 12 56 68 38 78
>
> Or via email : medical(dot)services(dot)eu(at)sony(dot)com
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>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com