> > Yes, pgpool-II exactly works as you described. Plus, with write query > > pgpool-II start a transaction if it's not already started by user. > > The write order is first A then B (if A is the first one on > > pgpool.conf). Commit order is B then A. > > > > If write query fails, pgpool-II aborts the transaction and start > > a degenration, which will be seen as connection shutdown from > > PostgreSQL server by client. By reconnecting pgpool-II, client can use > > the healthy PostgreSQL. > > > > Please note that "fail" does not mean here a query error (for example, > > violation of constraints). Rather "fail" means network error or > > PostgreSQL server down or some such. > Would not it be a good behavior to degenerate the backends that return a > query error while the master do not?
Currently pgpool-II just detects number of affected raws by INSERT/UPDATE/DELETE and reports errors. Next verion of pgpool-II will allow user to choose degeneration in this case or not in addition to reporting errors. -- Tatsuo Ishii SRA OSS, Inc. Japan English: http://www.sraoss.co.jp/index_en.php Japanese: http://www.sraoss.co.jp > I am concerned because I have an environment with seven backends in > load_balance_mode and it seems I can not be sure of the data integrity > of these backends in this mode. > > - -Ramon > > > > > >> If that's not how pgpool-II replication works, how does > >> it work? I've looked at the manual but I still don't > >> understand. > >> > >> I'm familiar with replication with Postgres 8 log shipping > >> (warm standby), Postgres 9 streaming replication > >> (hot standby), and Slony (hot standby). How does > >> Pgpool-II replication work and how does it compare to > >> the Postgres/Slony replication? > > > > They are all log(physical or logical one) based asynchronous > > replication systems. Pgpool-II is a query based synchronous > > replication. That's the big difference. In addition, those > > replication systems do not have any automatic failover/load balancing > > functionality while pgpool-II has. > > -- > > Tatsuo Ishii > > SRA OSS, Inc. Japan > > English: http://www.sraoss.co.jp/index_en.php > > Japanese: http://www.sraoss.co.jp > > _______________________________________________ > > Pgpool-general mailing list > > [email protected] > > http://pgfoundry.org/mailman/listinfo/pgpool-general > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.10 (GNU/Linux) > Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ > > iEYEARECAAYFAkwO2uMACgkQGIS0iEuhp4NKNwCeNFbkyQ8z6j+DkOkDKQaPCX3n > 6qgAoKEJUd4zZQ7jJvIX8EquM+CfNQv8 > =aW9f > -----END PGP SIGNATURE----- _______________________________________________ Pgpool-general mailing list [email protected] http://pgfoundry.org/mailman/listinfo/pgpool-general
