Thread: Enhancing online recovery in SR mode
Hi, I have just committed changes to enhance online recovery in streaming replication mode. Pgpool-II had to restart child process to recognize failback node. Now pgpool-II becomes a little bit smarter and does not need to restart children. This means that client sessions started before online recovery can continue while doing online recovery. The trick is to have local backend status cache in pgpool child. It copies backend status into local memory. Thus the process continues to disregard failback node until the session ends. Once the session ends, the process exits with status 1, and pgpool-II main restart new one, which will recognize failback node. Note that this enhancement is applied to pcp_attach_node as well. -- Tatsuo Ishii SRA OSS, Inc. Japan English: http://www.sraoss.co.jp/index_en.php Japanese: http://www.sraoss.co.jp
Oops. This should have been posted to pgpool-hackers. Sorry for noise. -- Tatsuo Ishii SRA OSS, Inc. Japan English: http://www.sraoss.co.jp/index_en.php Japanese: http://www.sraoss.co.jp > Hi, > > I have just committed changes to enhance online recovery in streaming > replication mode. Pgpool-II had to restart child process to recognize > failback node. Now pgpool-II becomes a little bit smarter and does not > need to restart children. This means that client sessions started > before online recovery can continue while doing online recovery. > > The trick is to have local backend status cache in pgpool child. It > copies backend status into local memory. Thus the process continues to > disregard failback node until the session ends. Once the session ends, > the process exits with status 1, and pgpool-II main restart new one, > which will recognize failback node. > > Note that this enhancement is applied to pcp_attach_node as well. > -- > Tatsuo Ishii > SRA OSS, Inc. Japan > English: http://www.sraoss.co.jp/index_en.php > Japanese: http://www.sraoss.co.jp > > -- > Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-hackers