Thread: Backup fatal issue

Backup fatal issue

From

mephysto

Date:

17 July 2015, 10:30:00

Hi there,
I have some problems in a postgres cluster when I try to execute a backup.
This is the log of entire operation:

LOG:  connection received: host=91.121.182.110 port=54957
LOG:  connection authorized: user=postgres database=postgres
LOG:  statement: BEGIN
LOG:  statement: SET application_name TO barman
LOG:  statement: SHOW "data_directory"
LOG:  connection received: host=91.121.182.110 port=54958
LOG:  connection authorized: user=postgres database=postgres
LOG:  statement: BEGIN
LOG:  statement: SET application_name TO barman
LOG:  statement: SELECT name, setting FROM pg_settings WHERE name IN
('config_file', 'hba_file', 'ident_file')
LOG:  connection received: host=91.121.182.110 port=54959
LOG:  connection authorized: user=postgres database=postgres
LOG:  statement: BEGIN
LOG:  statement: SET application_name TO barman
LOG:  statement: SELECT spcname, oid, pg_tablespace_location(oid) AS
spclocation FROM pg_tablespace WHERE pg_tablespace_location(oid) != ''
LOG:  connection received: host=91.121.182.110 port=54960
LOG:  connection authorized: user=postgres database=postgres
LOG:  statement: BEGIN
LOG:  statement: SET application_name TO barman
LOG:  statement: select pg_is_in_recovery()
LOG:  statement: SELECT xlog_loc, (pg_xlogfile_name_offset(xlog_loc)).*,
now() FROM pg_start_backup('Barman backup redevodb_citrix
20150717T091702',false) as xlog_loc
LOG:  connection received: host=91.121.182.110 port=54988
FATAL:  semctl(983046, 3, SETVAL, 0) failed: Invalid argument
LOG:  server process (PID 1756) exited with exit code 1
LOG:  terminating any other active server processes
WARNING:  terminating connection because of crash of another server process
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.
HINT:  In a moment you should be able to reconnect to the database and
repeat your command.
LOG:  all server processes terminated; reinitializing
LOG:  could not remove shared memory segment "/PostgreSQL.1804289383": No
such file or directory
LOG:  semctl(786432, 0, IPC_RMID, ...) failed: Invalid argument
LOG:  semctl(819201, 0, IPC_RMID, ...) failed: Invalid argument
LOG:  semctl(851970, 0, IPC_RMID, ...) failed: Invalid argument
LOG:  semctl(884739, 0, IPC_RMID, ...) failed: Invalid argument
LOG:  semctl(917508, 0, IPC_RMID, ...) failed: Invalid argument
LOG:  semctl(950277, 0, IPC_RMID, ...) failed: Invalid argument
LOG:  semctl(983046, 0, IPC_RMID, ...) failed: Invalid argument
LOG:  semctl(1015815, 0, IPC_RMID, ...) failed: Invalid argument
LOG:  database system was interrupted; last known up at 2015-07-17 09:18:10
CEST
LOG:  redo starts at 16/9F000028
LOG:  record with zero length at 16/9F000100
LOG:  redo done at 16/9F0000C8
LOG:  MultiXact member wraparound protections are now enabled
LOG:  database system is ready to accept connections
LOG:  autovacuum launcher started

Can anyone help me to identify and to resolve this inconvenience?

Thanks in advance.

Meph



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Re: Backup fatal issue

From

Melvin Davidson

Date:

17 July 2015, 16:12:35

I think we need just a little bit more information.

What is the O/S?

What is the PostgreSQL version?

What is the backup command?

Does this always occur with the same command?

Did you need to restarrt PostgreSQL after this started?

On Fri, Jul 17, 2015 at 3:29 AM, mephysto <mephystoonhell@gmail.com> wrote:

Hi there,
I have some problems in a postgres cluster when I try to execute a backup.
This is the log of entire operation:

LOG: connection received: host=91.121.182.110 port=54957
LOG: connection authorized: user=postgres database=postgres
LOG: statement: BEGIN
LOG: statement: SET application_name TO barman
LOG: statement: SHOW "data_directory"
LOG: connection received: host=91.121.182.110 port=54958
LOG: connection authorized: user=postgres database=postgres
LOG: statement: BEGIN
LOG: statement: SET application_name TO barman
LOG: statement: SELECT name, setting FROM pg_settings WHERE name IN
('config_file', 'hba_file', 'ident_file')
LOG: connection received: host=91.121.182.110 port=54959
LOG: connection authorized: user=postgres database=postgres
LOG: statement: BEGIN
LOG: statement: SET application_name TO barman
LOG: statement: SELECT spcname, oid, pg_tablespace_location(oid) AS
spclocation FROM pg_tablespace WHERE pg_tablespace_location(oid) != ''
LOG: connection received: host=91.121.182.110 port=54960
LOG: connection authorized: user=postgres database=postgres
LOG: statement: BEGIN
LOG: statement: SET application_name TO barman
LOG: statement: select pg_is_in_recovery()
LOG: statement: SELECT xlog_loc, (pg_xlogfile_name_offset(xlog_loc)).*,
now() FROM pg_start_backup('Barman backup redevodb_citrix
20150717T091702',false) as xlog_loc
LOG: connection received: host=91.121.182.110 port=54988
FATAL: semctl(983046, 3, SETVAL, 0) failed: Invalid argument
LOG: server process (PID 1756) exited with exit code 1
LOG: terminating any other active server processes
WARNING: terminating connection because of crash of another server process
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.
HINT: In a moment you should be able to reconnect to the database and
repeat your command.
LOG: all server processes terminated; reinitializing
LOG: could not remove shared memory segment "/PostgreSQL.1804289383": No
such file or directory
LOG: semctl(786432, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(819201, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(851970, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(884739, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(917508, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(950277, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(983046, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(1015815, 0, IPC_RMID, ...) failed: Invalid argument
LOG: database system was interrupted; last known up at 2015-07-17 09:18:10
CEST
LOG: redo starts at 16/9F000028
LOG: record with zero length at 16/9F000100
LOG: redo done at 16/9F0000C8
LOG: MultiXact member wraparound protections are now enabled
LOG: database system is ready to accept connections
LOG: autovacuum launcher started

Can anyone help me to identify and to resolve this inconvenience?

Thanks in advance.

Meph

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I reserve the right to fantasize. Whether or not you
wish to share my fantasy is entirely up to you.

Re: Backup fatal issue

From

Mephysto

Date:

17 July 2015, 17:08:15

Hi Melvin,

I am using Pstgres 9.4.4 in a virtualized Debian Linux 8.0. I do not know backup command because is launched by BARMAN 1.4.1. I have tried many times to execute the backup. I have restarted and reinstalled Postgres and I also rebooted OS many times.

Thanks for your help.

Meph

On 17 July 2015 at 15:12, Melvin Davidson <melvin6925@gmail.com> wrote:

I think we need just a little bit more information.

What is the O/S?
What is the PostgreSQL version?
What is the backup command?
Does this always occur with the same command?
Did you need to restarrt PostgreSQL after this started?

On Fri, Jul 17, 2015 at 3:29 AM, mephysto <mephystoonhell@gmail.com> wrote:
Hi there,
I have some problems in a postgres cluster when I try to execute a backup.
This is the log of entire operation:

LOG: connection received: host=91.121.182.110 port=54957
LOG: connection authorized: user=postgres database=postgres
LOG: statement: BEGIN
LOG: statement: SET application_name TO barman
LOG: statement: SHOW "data_directory"
LOG: connection received: host=91.121.182.110 port=54958
LOG: connection authorized: user=postgres database=postgres
LOG: statement: BEGIN
LOG: statement: SET application_name TO barman
LOG: statement: SELECT name, setting FROM pg_settings WHERE name IN
('config_file', 'hba_file', 'ident_file')
LOG: connection received: host=91.121.182.110 port=54959
LOG: connection authorized: user=postgres database=postgres
LOG: statement: BEGIN
LOG: statement: SET application_name TO barman
LOG: statement: SELECT spcname, oid, pg_tablespace_location(oid) AS
spclocation FROM pg_tablespace WHERE pg_tablespace_location(oid) != ''
LOG: connection received: host=91.121.182.110 port=54960
LOG: connection authorized: user=postgres database=postgres
LOG: statement: BEGIN
LOG: statement: SET application_name TO barman
LOG: statement: select pg_is_in_recovery()
LOG: statement: SELECT xlog_loc, (pg_xlogfile_name_offset(xlog_loc)).*,
now() FROM pg_start_backup('Barman backup redevodb_citrix
20150717T091702',false) as xlog_loc
LOG: connection received: host=91.121.182.110 port=54988
FATAL: semctl(983046, 3, SETVAL, 0) failed: Invalid argument
LOG: server process (PID 1756) exited with exit code 1
LOG: terminating any other active server processes
WARNING: terminating connection because of crash of another server process
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.
HINT: In a moment you should be able to reconnect to the database and
repeat your command.
LOG: all server processes terminated; reinitializing
LOG: could not remove shared memory segment "/PostgreSQL.1804289383": No
such file or directory
LOG: semctl(786432, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(819201, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(851970, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(884739, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(917508, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(950277, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(983046, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(1015815, 0, IPC_RMID, ...) failed: Invalid argument
LOG: database system was interrupted; last known up at 2015-07-17 09:18:10
CEST
LOG: redo starts at 16/9F000028
LOG: record with zero length at 16/9F000100
LOG: redo done at 16/9F0000C8
LOG: MultiXact member wraparound protections are now enabled
LOG: database system is ready to accept connections
LOG: autovacuum launcher started

Can anyone help me to identify and to resolve this inconvenience?

Thanks in advance.

Meph

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wish to share my fantasy is entirely up to you.

Re: Backup fatal issue

From

Melvin Davidson

Date:

17 July 2015, 17:16:58

If this is occurring with Barman, try doing a manual backup.

IE: pg_dump your_database > /tmp/somefile.sql

If that works, then the problem is with Barman or it's configuration.

On Fri, Jul 17, 2015 at 10:07 AM, Mephysto <mephystoonhell@gmail.com> wrote:

Hi Melvin,
I am using Pstgres 9.4.4 in a virtualized Debian Linux 8.0. I do not know backup command because is launched by BARMAN 1.4.1. I have tried many times to execute the backup. I have restarted and reinstalled Postgres and I also rebooted OS many times.

Thanks for your help.

Meph

On 17 July 2015 at 15:12, Melvin Davidson <melvin6925@gmail.com> wrote:
I think we need just a little bit more information.

What is the O/S?
What is the PostgreSQL version?
What is the backup command?
Does this always occur with the same command?
Did you need to restarrt PostgreSQL after this started?

On Fri, Jul 17, 2015 at 3:29 AM, mephysto <mephystoonhell@gmail.com> wrote:
Hi there,
I have some problems in a postgres cluster when I try to execute a backup.
This is the log of entire operation:

LOG: connection received: host=91.121.182.110 port=54957
LOG: connection authorized: user=postgres database=postgres
LOG: statement: BEGIN
LOG: statement: SET application_name TO barman
LOG: statement: SHOW "data_directory"
LOG: connection received: host=91.121.182.110 port=54958
LOG: connection authorized: user=postgres database=postgres
LOG: statement: BEGIN
LOG: statement: SET application_name TO barman
LOG: statement: SELECT name, setting FROM pg_settings WHERE name IN
('config_file', 'hba_file', 'ident_file')
LOG: connection received: host=91.121.182.110 port=54959
LOG: connection authorized: user=postgres database=postgres
LOG: statement: BEGIN
LOG: statement: SET application_name TO barman
LOG: statement: SELECT spcname, oid, pg_tablespace_location(oid) AS
spclocation FROM pg_tablespace WHERE pg_tablespace_location(oid) != ''
LOG: connection received: host=91.121.182.110 port=54960
LOG: connection authorized: user=postgres database=postgres
LOG: statement: BEGIN
LOG: statement: SET application_name TO barman
LOG: statement: select pg_is_in_recovery()
LOG: statement: SELECT xlog_loc, (pg_xlogfile_name_offset(xlog_loc)).*,
now() FROM pg_start_backup('Barman backup redevodb_citrix
20150717T091702',false) as xlog_loc
LOG: connection received: host=91.121.182.110 port=54988
FATAL: semctl(983046, 3, SETVAL, 0) failed: Invalid argument
LOG: server process (PID 1756) exited with exit code 1
LOG: terminating any other active server processes
WARNING: terminating connection because of crash of another server process
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.
HINT: In a moment you should be able to reconnect to the database and
repeat your command.
LOG: all server processes terminated; reinitializing
LOG: could not remove shared memory segment "/PostgreSQL.1804289383": No
such file or directory
LOG: semctl(786432, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(819201, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(851970, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(884739, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(917508, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(950277, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(983046, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(1015815, 0, IPC_RMID, ...) failed: Invalid argument
LOG: database system was interrupted; last known up at 2015-07-17 09:18:10
CEST
LOG: redo starts at 16/9F000028
LOG: record with zero length at 16/9F000100
LOG: redo done at 16/9F0000C8
LOG: MultiXact member wraparound protections are now enabled
LOG: database system is ready to accept connections
LOG: autovacuum launcher started

Can anyone help me to identify and to resolve this inconvenience?

Thanks in advance.

Meph

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Melvin Davidson
I reserve the right to fantasize. Whether or not you
wish to share my fantasy is entirely up to you.

Melvin Davidson
I reserve the right to fantasize. Whether or not you
wish to share my fantasy is entirely up to you.

Re: Backup fatal issue

From

Tom Lane

Date:

17 July 2015, 17:32:31

mephysto <mephystoonhell@gmail.com> writes:
> I have some problems in a postgres cluster when I try to execute a backup.
> ...
> FATAL:  semctl(983046, 3, SETVAL, 0) failed: Invalid argument
> ...
> LOG:  could not remove shared memory segment "/PostgreSQL.1804289383": No
> such file or directory
> LOG:  semctl(786432, 0, IPC_RMID, ...) failed: Invalid argument
> LOG:  semctl(819201, 0, IPC_RMID, ...) failed: Invalid argument
> LOG:  semctl(851970, 0, IPC_RMID, ...) failed: Invalid argument
> LOG:  semctl(884739, 0, IPC_RMID, ...) failed: Invalid argument
> LOG:  semctl(917508, 0, IPC_RMID, ...) failed: Invalid argument
> LOG:  semctl(950277, 0, IPC_RMID, ...) failed: Invalid argument
> LOG:  semctl(983046, 0, IPC_RMID, ...) failed: Invalid argument
> LOG:  semctl(1015815, 0, IPC_RMID, ...) failed: Invalid argument

Assuming you didn't manually destroy the shared memory segment and
semaphores, the only very likely explanation for this is that another
postmaster instance started up, used the same memory and semaphore
IDs, and then removed them when it shut down.  This should be impossible
given the interlocks around shared memory segment creation and use of
a data directory; but it's possible to break those interlocks if you
try hard enough.

I speculate that you've got a postmaster-startup script that
unconditionally removes the postmaster.pid lock file before starting the
postmaster, and that your backup procedure or some other routine action
is invoking that even when there might be a live postmaster already.

If so, the answer is simple: get rid of the script's attempt to remove the
lock file.  And have a word with whoever put it in.  *Nothing* except the
postmaster's own code should *ever* remove postmaster.pid.

            regards, tom lane

Re: Backup fatal issue

From

Mephysto

Date:

24 July 2015, 00:27:03

Hi Melvin,

I tried to execute pg_dump and after I tried to launch pg_start_backup and pg_stop_backup. In both cases, I did not receive any error, so I decided to investigate in BarMan.

Thanks for your help.

Bye.

Meph

On 17 July 2015 at 16:16, Melvin Davidson <melvin6925@gmail.com> wrote:

If this is occurring with Barman, try doing a manual backup.
IE: pg_dump your_database > /tmp/somefile.sql

If that works, then the problem is with Barman or it's configuration.

On Fri, Jul 17, 2015 at 10:07 AM, Mephysto <mephystoonhell@gmail.com> wrote:
Hi Melvin,
I am using Pstgres 9.4.4 in a virtualized Debian Linux 8.0. I do not know backup command because is launched by BARMAN 1.4.1. I have tried many times to execute the backup. I have restarted and reinstalled Postgres and I also rebooted OS many times.

Thanks for your help.

Meph

On 17 July 2015 at 15:12, Melvin Davidson <melvin6925@gmail.com> wrote:
I think we need just a little bit more information.

What is the O/S?
What is the PostgreSQL version?
What is the backup command?
Does this always occur with the same command?
Did you need to restarrt PostgreSQL after this started?

On Fri, Jul 17, 2015 at 3:29 AM, mephysto <mephystoonhell@gmail.com> wrote:
Hi there,
I have some problems in a postgres cluster when I try to execute a backup.
This is the log of entire operation:

LOG: connection received: host=91.121.182.110 port=54957
LOG: connection authorized: user=postgres database=postgres
LOG: statement: BEGIN
LOG: statement: SET application_name TO barman
LOG: statement: SHOW "data_directory"
LOG: connection received: host=91.121.182.110 port=54958
LOG: connection authorized: user=postgres database=postgres
LOG: statement: BEGIN
LOG: statement: SET application_name TO barman
LOG: statement: SELECT name, setting FROM pg_settings WHERE name IN
('config_file', 'hba_file', 'ident_file')
LOG: connection received: host=91.121.182.110 port=54959
LOG: connection authorized: user=postgres database=postgres
LOG: statement: BEGIN
LOG: statement: SET application_name TO barman
LOG: statement: SELECT spcname, oid, pg_tablespace_location(oid) AS
spclocation FROM pg_tablespace WHERE pg_tablespace_location(oid) != ''
LOG: connection received: host=91.121.182.110 port=54960
LOG: connection authorized: user=postgres database=postgres
LOG: statement: BEGIN
LOG: statement: SET application_name TO barman
LOG: statement: select pg_is_in_recovery()
LOG: statement: SELECT xlog_loc, (pg_xlogfile_name_offset(xlog_loc)).*,
now() FROM pg_start_backup('Barman backup redevodb_citrix
20150717T091702',false) as xlog_loc
LOG: connection received: host=91.121.182.110 port=54988
FATAL: semctl(983046, 3, SETVAL, 0) failed: Invalid argument
LOG: server process (PID 1756) exited with exit code 1
LOG: terminating any other active server processes
WARNING: terminating connection because of crash of another server process
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.
HINT: In a moment you should be able to reconnect to the database and
repeat your command.
LOG: all server processes terminated; reinitializing
LOG: could not remove shared memory segment "/PostgreSQL.1804289383": No
such file or directory
LOG: semctl(786432, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(819201, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(851970, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(884739, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(917508, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(950277, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(983046, 0, IPC_RMID, ...) failed: Invalid argument
LOG: semctl(1015815, 0, IPC_RMID, ...) failed: Invalid argument
LOG: database system was interrupted; last known up at 2015-07-17 09:18:10
CEST
LOG: redo starts at 16/9F000028
LOG: record with zero length at 16/9F000100
LOG: redo done at 16/9F0000C8
LOG: MultiXact member wraparound protections are now enabled
LOG: database system is ready to accept connections
LOG: autovacuum launcher started

Can anyone help me to identify and to resolve this inconvenience?

Thanks in advance.

Meph

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I reserve the right to fantasize. Whether or not you
wish to share my fantasy is entirely up to you.

--
Melvin Davidson
I reserve the right to fantasize. Whether or not you
wish to share my fantasy is entirely up to you.

Re: Backup fatal issue

From

Mephysto

Date:

24 July 2015, 00:27:46

Hi Tom,

I am using only pg_ctl to start and stop my database. At the moment I do not use any script.

Bye.

Meph

On 17 July 2015 at 16:32, Tom Lane <tgl@sss.pgh.pa.us> wrote:

mephysto <mephystoonhell@gmail.com> writes:
> I have some problems in a postgres cluster when I try to execute a backup.
> ...
> FATAL: semctl(983046, 3, SETVAL, 0) failed: Invalid argument
> ...
> LOG: could not remove shared memory segment "/PostgreSQL.1804289383": No
> such file or directory
> LOG: semctl(786432, 0, IPC_RMID, ...) failed: Invalid argument
> LOG: semctl(819201, 0, IPC_RMID, ...) failed: Invalid argument
> LOG: semctl(851970, 0, IPC_RMID, ...) failed: Invalid argument
> LOG: semctl(884739, 0, IPC_RMID, ...) failed: Invalid argument
> LOG: semctl(917508, 0, IPC_RMID, ...) failed: Invalid argument
> LOG: semctl(950277, 0, IPC_RMID, ...) failed: Invalid argument
> LOG: semctl(983046, 0, IPC_RMID, ...) failed: Invalid argument
> LOG: semctl(1015815, 0, IPC_RMID, ...) failed: Invalid argument

Assuming you didn't manually destroy the shared memory segment and
semaphores, the only very likely explanation for this is that another
postmaster instance started up, used the same memory and semaphore
IDs, and then removed them when it shut down. This should be impossible
given the interlocks around shared memory segment creation and use of
a data directory; but it's possible to break those interlocks if you
try hard enough.

I speculate that you've got a postmaster-startup script that
unconditionally removes the postmaster.pid lock file before starting the
postmaster, and that your backup procedure or some other routine action
is invoking that even when there might be a live postmaster already.

If so, the answer is simple: get rid of the script's attempt to remove the
lock file. And have a word with whoever put it in. *Nothing* except the
postmaster's own code should *ever* remove postmaster.pid.

regards, tom lane

Re: Backup fatal issue

From

mephysto

Date:

31 July 2015, 14:25:04

Hi all,
I am continuing to investigate and I found a probable malfunctioning in
linux semaphores: I foud postgres semaphores are deleted during barman
backup process. To executing test I have created a new empty postgres
cluster in a Debian Citrix virtual machine; this is output of ipcs -s
command:

Before start backup
postgres@postgres-1:/opt/postgres/pgclusters/barman_test/pg_log$ ipcs -s

------ Semaphore Arrays --------
key        semid      owner      perms      nsems
0x005b81c9 8912896    postgres   600        17
0x005b81ca 8945665    postgres   600        17
0x005b81cb 8978434    postgres   600        17
0x005b81cc 9011203    postgres   600        17
0x005b81cd 9043972    postgres   600        17
0x005b81ce 9076741    postgres   600        17
0x005b81cf 9109510    postgres   600        17
0x005b81d0 9142279    postgres   600        17

During backup
------ Semaphore Arrays --------
key        semid      owner      perms      nsems

After end of barman backup command
postgres@postgres-1:/opt/postgres/pgclusters/barman_test/pg_log$ ipcs -s

------ Semaphore Arrays --------
key        semid      owner      perms      nsems
0x005b81c9 9175040    postgres   600        17
0x005b81ca 9207809    postgres   600        17
0x005b81cb 9240578    postgres   600        17
0x005b81cc 9273347    postgres   600        17
0x005b81cd 9306116    postgres   600        17
0x005b81ce 9338885    postgres   600        17
0x005b81cf 9371654    postgres   600        17
0x005b81d0 9404423    postgres   600        17

The linux kernel version is 3.16.0-4-amd64

I have executed the same test with a database regularly backupped with
barman with the same version of postgres (9.4.4) and the semaphores are the
same before, during and after backup command execution. However in this case
the linux kernel version is 2.6.38.2-grsec-xxxx-grs-ipv6-64.


Do you think this semaphores anomaly can cause backup issue?

Do you have any suggestions to resolve it?

Thanks in advance.

Alessio



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