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On 06/08/2010 10:03 PM, Tatsuo Ishii wrote: >>> 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. So the only check I have in load balance mode is the health check? There is no data integrity checks? - -Ramon > -- > 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----- -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkwPElgACgkQGIS0iEuhp4P2aQCgqdwg8RvLNuUmLdIhWlHGoiBC EHwAniWa7M6iPorxh91Pc7amtwH8JRhO =VZYN -----END PGP SIGNATURE----- _______________________________________________ Pgpool-general mailing list [email protected] http://pgfoundry.org/mailman/listinfo/pgpool-general
