[pgpool-general: 8279] Re: pcp_recovery_node command fails

Todd Stein todd.stein at microfocus.com
Fri Jul 1 04:04:16 JST 2022 

Thank you to Tatsu Ishii.  I was able to get my cluster recovery process to work.  Still not 100% certain of the cause but believe it to be a mismatch of versions between the pgpool_recovery extension and pgpool.  I started over with a 2 node cluster and kept the parameter changes to a minimum.
Once that was working, I added a 3rd node by using the pcp_recovery_node command.


Regards,

Todd Stein


-----Original Message-----
From: pgpool-general <pgpool-general-bounces at pgpool.net> On Behalf Of Tatsuo Ishii
Sent: Friday, June 24, 2022 7:02 PM
To: Todd Stein <todd.stein at microfocus.com>
Cc: pgpool-general at pgpool.net
Subject: [pgpool-general: 8249] Re: pcp_recovery_node command fails

Where did you run the \dx command? You need to run \dx on the PostgreSQL primary node (probably catvmdxcpg12b.ftc.hpeswlab.net?).

> Looks like I have the same extension.
> postgres=# \dx pgpool_recovery
>                           List of installed extensions
>       Name       | Version | Schema |                Description
> -----------------+---------+--------+---------------------------------
> -----------------+---------+--------+----------
>  pgpool_recovery | 1.4     | public | recovery functions for pgpool-II for V4.3
> (1 row)
> 
> postgres=#

Where did you run the \dx command? You need to run \dx on the PostgreSQL primary node.

Also I suggest followings:

- Share pgpool.conf so that people (including me) confirm that your
  configuration and attempts are correct.

- Disable watchdog for now. At this point there are too many
  possibilities for the problem (exetnsion is not installed,
  pgpool.conf is not correct and/or unknown problem with
  watchdog). Once you confirm the system works, you can enable
  watchdog and continue testing. Let's proceed step by step.
  
> I want to run pcp_recovery_node command /usr/bin/pcp_recovery_node -d 
> -U postgres -h 16.78.121.246 -p 9898 -n 0
> 
> AFAIK the first step (stage) in the pcp_recovery_node process is to run the following:
> recovery_1st_stage_command = '/var/lib/pgsql/12/data/recovery_1st_stage'
> then the pgpool_remote_start script is run.
> 
> When the pcp_recovery_node command is run, it recieves the following list of arguments:
> 	PRIMARY_NODE_PGDATA=/var/lib/pgsql/12/data %R
> 	DEST_NODE_HOST=catvmdxcpg12a.ftc.hpeswlab.net %h
> 	DEST_NODE_PGDATA=/var/lib/pgsql/12/data %D
> 	PRIMARY_NODE_PORT=5432 %r
> 	DEST_NODE_ID=0 %d
> 	DEST_NODE_PORT=5432 %p
> 	PRIMARY_NODE_HOST=catvmdxcpg12b.ftc.hpeswlab.net %H
> 
> When the pgpool_remote_start script is run, it recieves the following list of arguments:
> 	DEST_NODE_HOST=catvmdxcpg12a.ftc.hpeswlab.net %h
> 	DEST_NODE_PGDATA=/var/lib/pgsql/12/data %D
> 	
> When I run /usr/bin/pcp_recovery_node, the following error is sent to stdout.
> 	-bash-4.2$ /usr/bin/pcp_recovery_node -U postgres -h 16.78.121.246 -p 9898 -n 0
> 	Password:
> 	ERROR:  executing recovery, execution of command failed at "1st stage"
> 	DETAIL:  command:"recovery_1st_stage"
> 	
> However, if I run the two scripts manually with the arguments, the process works.
> 
> -bash-4.2$ $PGDATA/recovery_1st_stage /var/lib/pgsql/12/data 
> catvmdxcpg12a.ftc.hpeswlab.net /var/lib/pgsql/12/data 5432 0 9898 
> catvmdxcpg12b.ftc.hpeswlab.net
> + MAIN_NODE_PGDATA=/var/lib/pgsql/12/data
> + DEST_NODE_HOST=catvmdxcpg12a.ftc.hpeswlab.net
> + DEST_NODE_PGDATA=/var/lib/pgsql/12/data
> + MAIN_NODE_PORT=5432
> + DEST_NODE_ID=0
> + DEST_NODE_PORT=9898
> + MAIN_NODE_HOST=catvmdxcpg12b.ftc.hpeswlab.net
> + PGHOME=/usr/pgsql-12
> + ARCHIVEDIR=/var/lib/pgsql/archivedir
> + REPLUSER=repl
> + MAX_DURATION=60
> + echo recovery_1st_stage: start: pg_basebackup for Standby node 0
> recovery_1st_stage: start: pg_basebackup for Standby node 0 ...
> ...
> recovery_1st_stage: end: recovery_1st_stage is completed successfully
> + exit 0
> 
> Next, manually run pgpool_remote_start:
> -bash-4.2$ $PGDATA/pgpool_remote_start catvmdxcpg12a.ftc.hpeswlab.net 
> /var/lib/pgsql/12/data
> + DEST_NODE_HOST=catvmdxcpg12a.ftc.hpeswlab.net
> + DEST_NODE_PGDATA=/var/lib/pgsql/12/data
> + PGHOME=/usr/pgsql-12
> + echo pgpool_remote_start: start: remote start Standby node 
> + catvmdxcpg12a.ftc.hpeswlab.net
> pgpool_remote_start: start: remote start Standby node 
> catvmdxcpg12a.ftc.hpeswlab.net
> + ssh -T -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null 
> + postgres at catvmdxcpg12a.ftc.hpeswlab.net -i 
> + /var/lib/pgsql/.ssh/id_rsa_pgpool ls /tmp
> Warning: Permanently added 'catvmdxcpg12a.ftc.hpeswlab.net,16.78.126.184' (ECDSA) to the list of known hosts.
> + '[' 0 -ne 0 ']'
> + ssh -T -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null postgres at catvmdxcpg12a.ftc.hpeswlab.net -i /var/lib/pgsql/.ssh/id_rsa_pgpool '
>     /usr/pgsql-12/bin/pg_ctl -l /dev/null -w -D /var/lib/pgsql/12/data 
> start '
> Warning: Permanently added 'catvmdxcpg12a.ftc.hpeswlab.net,16.78.126.184' (ECDSA) to the list of known hosts.
> waiting for server to start.... done
> server started
> + '[' 0 -ne 0 ']'
> + echo pgpool_remote_start: end: PostgreSQL on catvmdxcpg12a.ftc.hpeswlab.net is started successfully.
> pgpool_remote_start: end: PostgreSQL on catvmdxcpg12a.ftc.hpeswlab.net is started successfully.
> + exit 0
> -bash-4.2$
> 
> The postgres server did not start! (only according to systemctl status 
> postgresql-12 running pg_ctl status shows that it is running.
> 
> Looking at the replication_delay for node 0 shows a value of 67109080.
> All of the files in $PGDATA have a very recent time stamp indicating that pg_basebackup had run.

You can check the standby PostgreSQL log to see what's going on.

> Regards,
> 
> Todd Stein
> 
> -----Original Message-----
> From: Tatsuo Ishii <ishii at sraoss.co.jp>
> Sent: Thursday, June 23, 2022 7:46 PM
> To: Todd Stein <todd.stein at microfocus.com>
> Cc: jon.schewe at raytheon.com; pgpool-general at pgpool.net
> Subject: Re: [pgpool-general: 8244] Re: pcp_recovery_node command 
> fails
> 
>> Many responses recommended installing the pgpool_recovery extension, I had done it as part of the install.  My install was done with RPMs.
>> 
>> ERROR:  extension "pgpool_recovery" already exists
>> 2022-06-23 16:29:25.782 EDT [21981] STATEMENT:  CREATE EXTENSION 
>> pgpool_recovery; The recovery_1st_stage script came from a sample provided with the RPM version.  The only thing I should need to do with it is to adjust the path of $PGHOME.
> 
> It's apparent that the correct version of pgpool_recovery extension 
> was not installed or pgpool_recovery extension was not installed at 
> all. You can check it by following command using psql on the primary
> PostgreSQL:
> 
> test=# \dx pgpool_recovery
>                           List of installed extensions
>       Name       | Version | Schema |                Description                
> -----------------+---------+--------+---------------------------------
> -----------------+---------+--------+--
> -----------------+---------+--------+--------
>  pgpool_recovery | 1.4     | public | recovery functions for pgpool-II for V4.3
> (1 row)
> 
>> Regards,
>> 
>> Todd Stein
>> 
>> -----Original Message-----
>> From: Todd Stein
>> Sent: Thursday, June 23, 2022 4:08 PM
>> To: Jon SCHEWE <jon.schewe at raytheon.com>; pgpool-general at pgpool.net
>> Subject: RE: pcp_recovery_node command fails
>> 
>> This is the stdout:
>> ERROR:  executing recovery, execution of command failed at "1st stage"
>> DETAIL:  command:"recovery_1st_stage"
>> 
>> The pgpool logs don't have much useful info.  Even when I set them to debug, it's not very helpful.
>> 
>> This seems to be a pretty common issue, lots of people post about the issue, but I've not seen a resolution to it yet.
>> 
>> the postgres log is actually more useful:
>> ERROR:  function pgpool_recovery(unknown, unknown, unknown, unknown, 
>> integer, unknown, unknown) does not exist at character 8
>> 2022-06-23 16:03:53.740 EDT [25708] HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
>> 2022-06-23 16:03:53.740 EDT [25708] STATEMENT:  SELECT 
>> pgpool_recovery('recovery_1st_stage', 'nodea', 
>> '/var/lib/pgsql/12/data', '5432', 0, '5432', 'nodeb')
>> 
>> 
>> Regards,
>> 
>> Todd Stein
>> 
>> -----Original Message-----
>> From: pgpool-general <pgpool-general-bounces at pgpool.net> On Behalf Of 
>> Jon SCHEWE
>> Sent: Thursday, June 23, 2022 3:34 PM
>> To: Todd Stein <todd.stein at microfocus.com>; pgpool-general at pgpool.net
>> Subject: [pgpool-general: 8242] Re: pcp_recovery_node command fails
>> 
>>> I'm trying to use pcp_recovery_node for online recovery in a pgpool/postgresql-12 cluster.
>>> 
>>> My cluster has PostgreSQL 12.8 and pgpool 4.3.2 running on CentOS 7.9 linux.
>>> 
>>>  
>>> 
>>> I've tried so many things, I'll not go into those details just yet. 
>>> 
>>>  
>>> 
>>> To start with, here is the output of the pcp_recovery_node command:
>>> 
>>>  
>>> 
>>> pcp_recovery_node -U postgres -h <VIP> -p 9898 -n 0
>>> 
>>> Password:
>>> 
>>> ERROR:  executing recovery, execution of command failed at "1st stage"
>>> 
>>> DETAIL:  command:"recovery_1st_stage"
>>> 
>> 
>> Do you see anything in your logs about the errors? Usually this is either on stdout from the service or in /var/log/pgpool...
>> I'm guessing that your recovery_1st_stage script either isn't defined or isn't doing what you expect.
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