WAL files not being recycled

Scott Moynes wrote:

I have a PostgreSQL server that is not recycling WAL files. Log files are
continually created and no old log files are ever removed.

Running PostgreSQL v 9.4.8 with archive settings:

archive_mode = on
archive_command = /bin/true

Checkpoint logging is enabled and does not record any logs being recycled:

See the wal_keep_segments option, as well as existance of any
replication slot (select * from pg_replication_slots).

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On 05/16/2016 03:33 PM, Scott Moynes wrote:

I have a PostgreSQL server that is not recycling WAL files. Log files
are continually created and no old log files are ever removed.

Running PostgreSQL v 9.4.8 with archive settings:

archive_mode = on
archive_command = /bin/true

Checkpoint logging is enabled and does not record any logs being recycled:

2016-05-16 00:05:37 EDT - LOG: checkpoint starting: xlog
2016-05-16 00:09:51 EDT - LOG: checkpoint complete: wrote 38574
buffers (29.4%); 0 transaction log file(s) added, 0 removed, 0 recycled;
write=252.921 s, sync=1.340 s, total=254.312 s; sync files=48,
longest=1.101 s, average=0.027 s
2016-05-16 00:10:37 EDT - LOG: checkpoint starting: time
2016-05-16 00:14:11 EDT - LOG: checkpoint complete: wrote 43786
buffers (33.4%); 0 transaction log file(s) added, 0 removed, 0 recycled;
write=206.271 s, sync=7.428 s, total=213.765 s; sync files=82,
longest=3.821 s, average=0.090 s
...
2016-05-16 07:32:27 EDT - LOG: checkpoint complete: wrote 7617
buffers (5.8%); 1 transaction log file(s) added, 0 removed, 0 recycled;
write=269.3

Control data records:

pg_control last modified: Mon 16 May 2016 06:23:07 PM EDT
Latest checkpoint location: 1EB/1F008FE8
Prior checkpoint location: 1EB/1E0009E0
Latest checkpoint's REDO location: 1EB/1F008FB0

There is a single replication client:

pid | 23287
usesysid | 10
usename | postgres
application_name | walreceiver
client_addr | 172.16.56.246
client_hostname |
client_port | 58070
backend_start | 2016-05-14 03:27:33.523611+00
backend_xmin |
state | streaming
sent_location | 1EB/1F042760
write_location | 1EB/1F042760
flush_location | 1EB/1F042760
replay_location | 1EB/1F037F40
sync_priority | 0
sync_state | async

Does anyone have suggestions what else to check? What can cause WALs not
to be recycled or removed?

http://www.postgresql.org/docs/9.4/interactive/runtime-config-replication.html#RUNTIME-CONFIG-REPLICATION-MASTER

"wal_keep_segments (integer)

Specifies the minimum number of past log file segments kept in the
pg_xlog directory, in case a standby server needs to fetch them for
streaming replication. Each segment is normally 16 megabytes. If a
standby server connected to the sending server falls behind by more than
wal_keep_segments segments, the sending server might remove a WAL
segment still needed by the standby, in which case the replication
connection will be terminated. Downstream connections will also
eventually fail as a result. (However, the standby server can recover by
fetching the segment from archive, if WAL archiving is in use.)

This sets only the minimum number of segments retained in pg_xlog;
the system might need to retain more segments for WAL archival or to
recover from a checkpoint. If wal_keep_segments is zero (the default),
the system doesn't keep any extra segments for standby purposes, so the
number of old WAL segments available to standby servers is a function of
the location of the previous checkpoint and status of WAL archiving.
This parameter can only be set in the postgresql.conf file or on the
server command line.
"

Thanks in advance.

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Scott Moynes
VM Farms

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Adrian Klaver
adrian.klaver@aklaver.com

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wal_keep_segments is set to 32.

Here is the replication slot:

slot_name |
n6lbb2vmohwuxoyk_00018732_f58b5354_79ad_4e6e_b18b_47acb1d7ce1f
plugin | test_decoding
slot_type | logical
datoid | 18732
database | omitted
active | f
xmin |
catalog_xmin | 84884044
restart_lsn | 1B3/4300CA60

Can an inactive replication slot cause WALs to be retained?

On Mon, May 16, 2016 at 3:44 PM, Alvaro Herrera <alvherre@2ndquadrant.com>
wrote:

Scott Moynes wrote:

I have a PostgreSQL server that is not recycling WAL files. Log files are
continually created and no old log files are ever removed.

Running PostgreSQL v 9.4.8 with archive settings:

archive_mode = on
archive_command = /bin/true

Checkpoint logging is enabled and does not record any logs being

recycled:

See the wal_keep_segments option, as well as existance of any
replication slot (select * from pg_replication_slots).

--
Álvaro Herrera http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

--
Scott Moynes
VM Farms

On 17/05/16 00:54, Scott Moynes wrote:

wal_keep_segments is set to 32.

Here is the replication slot:

slot_name |
n6lbb2vmohwuxoyk_00018732_f58b5354_79ad_4e6e_b18b_47acb1d7ce1f
plugin | test_decoding
slot_type | logical
datoid | 18732
database | omitted
active | f
xmin |
catalog_xmin | 84884044
restart_lsn | 1B3/4300CA60

Can an inactive replication slot cause WALs to be retained?

Absolutely! That's what they're for.

If you don't expect this slot to re-become active, you should drop it.
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http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support

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