Max number of WAL files in pg_xlog directory for Postgres 9.2 version

Hi,

This page in the documentation can help you.
https://www.postgresql.org/docs/9.2/static/wal-configuration.html

Best Regards,
Johnes Castro
PostgreSQL: Documentation: 9.2: WAL Configuration<https://www.postgresql.org/docs/9.2/static/wal-configuration.html&gt;
29.4. WAL Configuration. There are several WAL-related configuration parameters that affect database performance.This section explains their use. Consult Chapter 18 for general information about setting server configuration parameters.. Checkpoints are points in the sequence of transactions at which it is guaranteed that the heap and index data files have been updated with all information ...
www.postgresql.org

________________________________
De: Raghavendra Rao J S V <raghavendrajsv@gmail.com>
Enviado: quarta-feira, 5 de setembro de 2018 15:39
Para: pgsql-general@lists.postgresql.org
Assunto: Max number of WAL files in pg_xlog directory for Postgres 9.2 version

Hi All,

We are using postgres 9.2 verstion database.

Please let me know, how many max number of wal files in pg_xlog directory?

What is the formul. I am seeing different formulas. Could you provide me which decides number of max WAL files in PG_XLOG directory for Postgres 9.2 Database,please?

--
Regards,
Raghavendra Rao J S V

1 wal by default occupies 16MB.
The parameter in version 9.2 that controls this is: wal_keep_segments

By setting the parameter to 10, the maximum size of the US pg_xlog will be 160MB.

Best Regards,
Johnes Castro

________________________________
De: Johnes Castro <johnescm@hotmail.com>
Enviado: quarta-feira, 5 de setembro de 2018 15:48
Para: Raghavendra Rao J S V; pgsql-general@lists.postgresql.org
Assunto: RE: Max number of WAL files in pg_xlog directory for Postgres 9.2 version

Hi,

This page in the documentation can help you.
https://www.postgresql.org/docs/9.2/static/wal-configuration.html

Best Regards,
Johnes Castro
PostgreSQL: Documentation: 9.2: WAL Configuration<https://www.postgresql.org/docs/9.2/static/wal-configuration.html&gt;
29.4. WAL Configuration. There are several WAL-related configuration parameters that affect database performance.This section explains their use. Consult Chapter 18 for general information about setting server configuration parameters.. Checkpoints are points in the sequence of transactions at which it is guaranteed that the heap and index data files have been updated with all information ...
www.postgresql.org

________________________________
De: Raghavendra Rao J S V <raghavendrajsv@gmail.com>
Enviado: quarta-feira, 5 de setembro de 2018 15:39
Para: pgsql-general@lists.postgresql.org
Assunto: Max number of WAL files in pg_xlog directory for Postgres 9.2 version

Hi All,

We are using postgres 9.2 verstion database.

Please let me know, how many max number of wal files in pg_xlog directory?

What is the formul. I am seeing different formulas. Could you provide me which decides number of max WAL files in PG_XLOG directory for Postgres 9.2 Database,please?

--
Regards,
Raghavendra Rao J S V

On 09/05/2018 12:39 PM, Raghavendra Rao J S V wrote:

Hi All,

We are using postgres 9.2 verstion database.

Please let me know, how many max number of wal files in pg_xlog directory?

What is the formul. I am seeing different formulas. Could you provide me
which decides number of max WAL files in PG_XLOG directory for Postgres
9.2 Database,please?

If you're doing WAL file replication, and -- for whatever reason -- the
standby system isn't applying them fast enough, there could be tens of
thousands of files in pg_xlog.  (It would drain pretty quickly when you
resolve the problem, though.)

--
Angular momentum makes the world go 'round.

Am 05.09.2018 um 19:39 schrieb Raghavendra Rao J S V:

Hi All,

We are using postgres 9.2 verstion database.

9.2 is out of support. Please consider a upgrade. soon!

Please let me know, how many max number of wal files in pg_xlog directory?

depends on the workload and on several settings. There is no rule of thumb.

Regards, Andreas
--

2ndQuadrant - The PostgreSQL Support Company.
www.2ndQuadrant.com

Hi John,

As you said, I have gone through the document. Which one is correct [(2 +
checkpoint_completion_target) * checkpoint_segments + 1 *or*
checkpoint_segments + wal_keep_segments
<https://www.postgresql.org/docs/9.2/static/runtime-config-replication.html#GUC-WAL-KEEP-SEGMENTS&gt;
+
1 files] for 9.2 PostgreSQL?

In my environment we have kept *wal_keep_segments* and *checkpoint_segments*
as below. Will it cause any negative impact?

*checkpoint_segments = 128* # in logfile segments, min 1, 16MB each
#checkpoint_timeout = 5min # range 30s-1h
#checkpoint_completion_target = 0.5 # checkpoint target duration, 0.0 - 1.0
#checkpoint_warning = 30s # 0 disables
*#wal_keep_segments = 0* # in logfile segments, 16MB each; 0 disables

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

There will always be at least one WAL segment file, and will normally not
be more than (2 + checkpoint_completion_target) * checkpoint_segments + 1
or checkpoint_segments + wal_keep_segments
<https://www.postgresql.org/docs/9.2/static/runtime-config-replication.html#GUC-WAL-KEEP-SEGMENTS&gt;
+
1 files. Each segment file is normally 16 MB (though this size can be
altered when building the server). You can use this to estimate space
requirements for WAL. Ordinarily, when old log segment files are no longer
needed, they are recycled (renamed to become the next segments in the
numbered sequence). If, due to a short-term peak of log output rate, there
are more than 3 * checkpoint_segments + 1 segment files, the unneeded
segment files will be deleted instead of recycled until the system gets
back under this limit.

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Regards,
Raghavendra Rao

On Wed, 5 Sep 2018 at 23:23, Johnes Castro <johnescm@hotmail.com> wrote:

1 wal by default occupies 16MB.
The parameter in version 9.2 that controls this is: wal_keep_segments

By setting the parameter to 10, the maximum size of the US pg_xlog will be
160MB.

Best Regards,
Johnes Castro

------------------------------
*De:* Johnes Castro <johnescm@hotmail.com>
*Enviado:* quarta-feira, 5 de setembro de 2018 15:48
*Para:* Raghavendra Rao J S V; pgsql-general@lists.postgresql.org
*Assunto:* RE: Max number of WAL files in pg_xlog directory for Postgres
9.2 version

Hi,

This page in the documentation can help you.
https://www.postgresql.org/docs/9.2/static/wal-configuration.html

Best Regards,
Johnes Castro
PostgreSQL: Documentation: 9.2: WAL Configuration
<https://www.postgresql.org/docs/9.2/static/wal-configuration.html&gt;
29.4. WAL Configuration. There are several WAL-related configuration
parameters that affect database performance.This section explains their
use. Consult Chapter 18 for general information about setting server
configuration parameters.. Checkpoints are points in the sequence of
transactions at which it is guaranteed that the heap and index data files
have been updated with all information ...
www.postgresql.org

------------------------------
*De:* Raghavendra Rao J S V <raghavendrajsv@gmail.com>
*Enviado:* quarta-feira, 5 de setembro de 2018 15:39
*Para:* pgsql-general@lists.postgresql.org
*Assunto:* Max number of WAL files in pg_xlog directory for Postgres 9.2
version

Hi All,

We are using postgres 9.2 verstion database.

Please let me know, how many max number of wal files in pg_xlog directory?

What is the formul. I am seeing different formulas. Could you provide me
which decides number of max WAL files in PG_XLOG directory for Postgres 9.2
Database,please?

--
Regards,
Raghavendra Rao J S V

--
Regards,
Raghavendra Rao J S V
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