[Pgpool-general] failback setup problem

[Tatsuo Ishii]

>> > I have a different approach of recovering the postgres server. I'm
>> > recovering from an existing backup. I do that because it is faster and I
>> > don't put additional i/o load on the just activated server. I guess (or
>> > hope) most people will have an existing backup.
>> >
>> > So my question is - if the aproach of recovering the failed server via a
>> sql
>> > command is optimal? What if both servers failed? then I'm not able to use
>> > pcp-tools or pgpoolAdmin for recovering?
>>
>> I'm not sure what you are trying to do here. If "backup" means it was
>> created by pg_dump_all, I don't think your approach works. Streaming
>> replication requires a base backup(binary backup) which is managed by
>> pg_start_backup/pg_stop_backup.
>>
> 
> Yes of course I have a backup created as described in
> http://www.postgresql.org/docs/9.0/static/continuous-archiving.html#BACKUP-BASE-BACKUP
> .
> 
> My question is, what happens if both server failed somehow? Can I still use
> pgpoolAdmin to recover a database server?

No, pgpoolAdmin cannot recover a database server in this situation.
You have to recover the database manualy.
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp

> Best..
> Uwe
> 
> 
> 
>>
>> > I'm asking because I worked for several years as an
>> > it-production-responsible and I learned a little how administrators
>> > think/work. They are happy if they have a (or better ONE) defined
>> recovery
>> > procedure.
>> > Where am I getting? I'm asking you if it would makes sense to recode or
>> > reduce the recovery procedure code to one system call e.g.
>> failback_command.
>> > Most people have their backup and restore functionality coded and ready
>> for
>> > training and/or desaster. If they could simply use this very same
>> > functionality within pgpooladmin that would be great.
>> >
>> > It might be that i have overseen something (as before) and this is
>> already
>> > possible. If so please tell me how.
>> >
>> > Best Regards,
>> > Uwe
>> >
>> >
>> > On 26 April 2011 07:34, Tatsuo Ishii <ishii at sraoss.co.jp> wrote:
>> >
>> >> > thanks, that message already helped. I tried to recover the postgres
>> >> server
>> >> > with the failback_command.
>> >>
>> >> You are welcome.
>> >>
>> >> > I didn't realize these recovery_* parameters yet.
>> >> > So I use the recovery_* parameters for recovering the failed postgres
>> >> > server.
>> >>
>> >> pgpool-II connects to backend to issue some SQLs including CHECKPOINT.
>> >> recovery_* parameters define the user and password for the connection.
>> >> Usually they are for PostgreSQL super user (postgres).
>> >>
>> >> > And the failback_command to attach the postgres server into pgpool
>> >> > right?
>> >>
>> >> If you want to do something special, for example mailing to DBA, then
>> >> you might want to specify it.  Otherwise you can leave it empty.
>> >> --
>> >> Tatsuo Ishii
>> >> SRA OSS, Inc. Japan
>> >> English: http://www.sraoss.co.jp/index_en.php
>> >> Japanese: http://www.sraoss.co.jp
>> >>
>> >> > Best Regards,
>> >> > Uwe
>> >> >
>> >> >
>> >> > On 26 April 2011 01:06, Tatsuo Ishii <ishii at sraoss.co.jp> wrote:
>> >> >
>> >> >> > I'm using pg-pool-II 3.0.3 with streaming replication.
>> >> >> > I coded the failback scenario/script for the slave server and the
>> >> script
>> >> >> > itself works fine.
>> >> >> >
>> >> >> > I now configured the failback script in pgpool.conf and during
>> testing
>> >> an
>> >> >> > error message comes up:
>> >> >> > 2011-04-09 06:42:18 LOG:   pid 16863: starting recovering node 1
>> >> >> > 2011-04-09 06:42:18 ERROR: pid 16863: start_recover: could not
>> connect
>> >> >> > master node.
>> >> >> >
>> >> >> > [root at adt-web01 pgpool-II-3.0.3]# pcp_node_info 10 adt-web01 9898
>> >> >> postgres
>> >> >> > postgres 0
>> >> >> > adt-db01 5432 1 0.500000
>> >> >> > [root at adt-web01 pgpool-II-3.0.3]# pcp_node_info 10 adt-web01 9898
>> >> >> postgres
>> >> >> > postgres 1
>> >> >> > adt-db02 5432 3 0.500000
>> >> >> >
>> >> >> > pcp commands and pgpooladmin report that the master is up and
>> running
>> >> and
>> >> >> > I'm able to connect to the master directly and through pgpool.
>> >> >> > So what's wrong? So far everything else works fine.
>> >> >>
>> >> >> Assuming you have set recovery_user and recovery_passwd correctly,
>> I'm
>> >> >> not sure what's going on. IMO, the error message is very rare. It's
>> so
>> >> >> rare and there's a bug in the error path, which had not been found
>> for
>> >> >> long time. Can please try attached patch? The patch add a little bit
>> >> >> usefull info to the error message above.
>> >> >> --
>> >> >> Tatsuo Ishii
>> >> >> SRA OSS, Inc. Japan
>> >> >> English: http://www.sraoss.co.jp/index_en.php
>> >> >> Japanese: http://www.sraoss.co.jp
>> >> >>
>> >>
>>