Thread: missing client_hostname

missing client_hostname

From
Atul Kumar
Date:
Hi,

I have postgres 12 running in centos7.

I recently have configured streaming replication from master to standby using below command:

/usr/bin/pg_basebackup -h <master ip> -p 5432 -U replication -D /path/of/data/directory/ -Fp -R -Xs -P -c fast

It was successfully configured but when I query pg_stat_replication I don't get the hostname in output:

postgres=# select * from pg_stat_Replication;
-[ RECORD 1 ]----+------------------------------
pid              | 3692075
usesysid         | 16384
usename          | replication
application_name | walreceiver
client_addr      | slave_ip
client_hostname  |
client_port      | 52500
backend_start    | 2023-11-01 08:26:45.373297-07
backend_xmin     |
state            | streaming
sent_lsn         | 2E5/400001C0
write_lsn        | 2E5/400001C0
flush_lsn        | 2E5/400001C0
replay_lsn       | 2E5/400001C0
write_lag        |
flush_lag        |
replay_lag       |
sync_priority    | 0
sync_state       | async
reply_time       | 2023-11-01 08:41:47.60122-07


So please help me understand the reason for this and how I will fix this issue of having a respective hostname in this catalog.



Regards,
Atul

Re: missing client_hostname

From
Christoph Moench-Tegeder
Date:
## Atul Kumar (akumar14871@gmail.com):

> It was successfully configured but when I query pg_stat_replication I don't
> get the hostname in output:

I Recommend The Fine Manual:
https://www.postgresql.org/docs/current/monitoring-stats.html#MONITORING-PG-STAT-REPLICATION-VIEW
"... and only when log_hostname is enabled".

Regards,
Christoph

-- 
Spare Space



Re: missing client_hostname

From
Atul Kumar
Date:
I have already enabled log_hostname, still  client_hostname is not showing up.

Do you think that just because I use ip instead of hostname while using pg_basebackup could be the reason for it ?




Regards,
Atul

On Wed, Nov 1, 2023 at 11:23 PM Christoph Moench-Tegeder <cmt@burggraben.net> wrote:
## Atul Kumar (akumar14871@gmail.com):

> It was successfully configured but when I query pg_stat_replication I don't
> get the hostname in output:

I Recommend The Fine Manual:
https://www.postgresql.org/docs/current/monitoring-stats.html#MONITORING-PG-STAT-REPLICATION-VIEW
"... and only when log_hostname is enabled".

Regards,
Christoph

--
Spare Space

Re: missing client_hostname

From
Mateusz Henicz
Date:
Did you reconnect your replica after enabling log_hostname? If not, then do it and check again.

śr., 1 lis 2023, 19:03 użytkownik Atul Kumar <akumar14871@gmail.com> napisał:
I have already enabled log_hostname, still  client_hostname is not showing up.

Do you think that just because I use ip instead of hostname while using pg_basebackup could be the reason for it ?




Regards,
Atul

On Wed, Nov 1, 2023 at 11:23 PM Christoph Moench-Tegeder <cmt@burggraben.net> wrote:
## Atul Kumar (akumar14871@gmail.com):

> It was successfully configured but when I query pg_stat_replication I don't
> get the hostname in output:

I Recommend The Fine Manual:
https://www.postgresql.org/docs/current/monitoring-stats.html#MONITORING-PG-STAT-REPLICATION-VIEW
"... and only when log_hostname is enabled".

Regards,
Christoph

--
Spare Space

Re: missing client_hostname

From
Atul Kumar
Date:
Yes, I have already tried that as log_hostname was already enabled by me.

By the way, just to inform you that the log_hostname is used for logging the hostname instead of ip addresses in error log files only, Please correct me if I am wrong.

Could you help me in telling my query that Iasked in my trial mail:

"Do you think that just because I use ip_address instead of hostname while using pg_basebackup on standby side could be the reason for not showing client_hostname in pg_stat_replication ?" I used below command in standby node:

/usr/bin/pg_basebackup -h <master ip> -p 5432 -U replication -D /path/of/data/directory/ -Fp -R -Xs -P -c fast


Regards.




On Wed, Nov 1, 2023 at 11:46 PM Mateusz Henicz <mateuszhenicz@gmail.com> wrote:
Did you reconnect your replica after enabling log_hostname? If not, then do it and check again.

śr., 1 lis 2023, 19:03 użytkownik Atul Kumar <akumar14871@gmail.com> napisał:
I have already enabled log_hostname, still  client_hostname is not showing up.

Do you think that just because I use ip instead of hostname while using pg_basebackup could be the reason for it ?




Regards,
Atul

On Wed, Nov 1, 2023 at 11:23 PM Christoph Moench-Tegeder <cmt@burggraben.net> wrote:
## Atul Kumar (akumar14871@gmail.com):

> It was successfully configured but when I query pg_stat_replication I don't
> get the hostname in output:

I Recommend The Fine Manual:
https://www.postgresql.org/docs/current/monitoring-stats.html#MONITORING-PG-STAT-REPLICATION-VIEW
"... and only when log_hostname is enabled".

Regards,
Christoph

--
Spare Space

Re: missing client_hostname

From
Christoph Moench-Tegeder
Date:
Hi,

please don't top-post.

## Atul Kumar (akumar14871@gmail.com):

> I have already enabled log_hostname, still  *client_hostname is not showing
> up.*

It's always helpful to mention relevant non-default settings along
with the question. Was log_hostname really active at backup start
time? (Check pg_settings before starting the backup). Can the server
actually resolve the IP address to a host name?

> Do you think that just because I use ip instead of hostname while using
> pg_basebackup could be the reason for it ?

No.

Regards,
Christoph

-- 
Spare Space