Thread: PG11.2 - wal_level =minimal max_wal_senders = 0
Hello,
I have recently upgraded 10 Postgres databases to 11.2, these databases are used for data warehousing / ETL. These are stand alone systems, no replication. They perform a lot of inserts, drop tables and create tables etc…
I have been working on tuning the databases, I am seeing the following in the log:
2019-09-03 10:40:21.660 EDT [5635] LOG: checkpoints are occurring too frequently (13 seconds apart)
2019-09-03 10:40:21.660 EDT [5635] HINT: Consider increasing the configuration parameter "max_wal_size".
My first thought was to increase the max_wal_size which may take care of the logged message. Then I looked at the wal_level setting. I see that it defaults to replica out of the box and max_wal_senders = 10.
postgres=# show wal_level;
wal_level
-----------
replica
(1 row)
postgres=# show max_wal_senders;
max_wal_senders
-----------------
10
(1 row)
The question I have is, for a production database not doing replication, can I safely set the following parameters, I understand that minimal will also disable wal_archiving so I am concerned about that as well.
wal_level = minimal
max_wal_senders = 0
I have been looking at the documentation and I guess I am looking for a yes this is ok, I figured it’s on by default for a reason so I was hesitant to change it.
Jason Ralph
On Wed, Sep 4, 2019 at 5:15 PM Jason Ralph <jralph@affinitysolutions.com> wrote: > The question I have is, for a production database not doing replication, can I safely set the following parameters, I understandthat minimal will also disable wal_archiving so I am concerned about that as well. > > wal_level = minimal > > max_wal_senders = 0 > > > > I have been looking at the documentation and I guess I am looking for a yes this is ok, I figured it’s on by default fora reason so I was hesitant to change it. I don't see why you should not set them as you described. The idea is that the overhead of having replica over minimal is today enough "low" in contrast to the need for replication (e.g., backup tools like pgbackrest). Luca
Thank you Luca, Can I ask one more related question, I have no need for replication as noted below, can I safely disable the worker processvia the setting below? In my sandbox it does turn off the logical replication launcher, I just wanted to be sure Iam not affecting anything other than replication with this setting. max_logical_replication_workers = 0 # taken from max_worker_processes # (change requires restart) Jason Ralph -----Original Message----- From: Luca Ferrari <fluca1978@gmail.com> Sent: Wednesday, September 4, 2019 12:16 PM To: Jason Ralph <jralph@affinitysolutions.com> Cc: pgsql-general@lists.postgresql.org Subject: Re: PG11.2 - wal_level =minimal max_wal_senders = 0 On Wed, Sep 4, 2019 at 5:15 PM Jason Ralph <jralph@affinitysolutions.com> wrote: > The question I have is, for a production database not doing replication, can I safely set the following parameters, I understandthat minimal will also disable wal_archiving so I am concerned about that as well. > > wal_level = minimal > > max_wal_senders = 0 > > > > I have been looking at the documentation and I guess I am looking for a yes this is ok, I figured it’s on by default fora reason so I was hesitant to change it. I don't see why you should not set them as you described. The idea is that the overhead of having replica over minimal is today enough "low" in contrast to the need for replication(e.g., backup tools like pgbackrest). Luca This message contains confidential information and is intended only for the individual named. If you are not the named addresseeyou should not disseminate, distribute or copy this e-mail. Please notify the sender immediately by e-mail if youhave received this e-mail by mistake and delete this e-mail from your system. E-mail transmission cannot be guaranteedto be secure or error-free as information could be intercepted, corrupted, lost, destroyed, arrive late or incomplete,or contain viruses. The sender therefore does not accept liability for any errors or omissions in the contentsof this message, which arise as a result of e-mail transmission. If verification is required please request a hard-copyversion.
On Wed, Sep 4, 2019 at 10:44 PM Jason Ralph <jralph@affinitysolutions.com> wrote: > > Thank you Luca, > Can I ask one more related question, I have no need for replication as noted below, can I safely disable the worker processvia the setting below? In my sandbox it does turn off the logical replication launcher, I just wanted to be sure Iam not affecting anything other than replication with this setting. > > > max_logical_replication_workers = 0 # taken from max_worker_processes > # (change requires restart) > Quite frankly I've never done, but I don't see why you should not turn it off. Luca
On Wed, Sep 4, 2019 at 10:44 PM Jason Ralph
<jralph@affinitysolutions.com> wrote:
>
> Thank you Luca,
> Can I ask one more related question, I have no need for replication as noted below, can I safely disable the worker process via the setting below? In my sandbox it does turn off the logical replication launcher, I just wanted to be sure I am not affecting anything other than replication with this setting.
>
>
> max_logical_replication_workers = 0 # taken from max_worker_processes
> # (change requires restart)
>
Quite frankly I've never done, but I don't see why you should not turn it off.
Luca
Sent: Friday, September 6, 2019 3:41:44 AM
To: Luca Ferrari <fluca1978@gmail.com>
Cc: Jason Ralph <jralph@affinitysolutions.com>; pgsql-general@lists.postgresql.org <pgsql-general@lists.postgresql.org>
Subject: Re: PG11.2 - wal_level =minimal max_wal_senders = 0
On Wed, Sep 4, 2019 at 10:44 PM Jason Ralph
<jralph@affinitysolutions.com> wrote:
>
> Thank you Luca,
> Can I ask one more related question, I have no need for replication as noted below, can I safely disable the worker process via the setting below? In my sandbox it does turn off the logical replication launcher, I just wanted to be sure I am not affecting anything other than replication with this setting.
>
>
> max_logical_replication_workers = 0 # taken from max_worker_processes
> # (change requires restart)
>
Quite frankly I've never done, but I don't see why you should not turn it off.
Luca
On Sat, Sep 7, 2019 at 2:15 AM Jason Ralph <jralph@affinitysolutions.com> wrote: > I currently have the systems running a parallel pg_dump each night to a separate partition mounted on the VM. Then I performa full backup of the VM and all mounted drives each night. Would this be affected by disabling wal archiving? I notedthat I understood wal archiving was affected in my initial question. But I was not able to see how it could affect mysetup. Please school me if I am being naive. No, if you are using pg_dump you are not affected by archiving. Archiving is used to backup with tools like pgbackrest, barman, wal-e and alike. If you are running your database isolated (i.e., no slaves, no advanced backups), running it without replication level in wal and using only pg_dump is fine. Luca