> Am 15.04.2010 06:34, Tatsuo Ishii wrote: > > >> 2. Is there a way to attach multiple nodes in an "atomic" way? > > > > Why do you need atomicity for this? > > Because only then it is guaranteed that the databases will be in sync. > > Consider this: > > 1. pgpool with 2 backends > 2. 2 backends are detached for some reason (i.e. switch/cabling changes, > pgpool sitting on a different host than the databases) > 3. clients are trying to write to pgpool continuously > 4. switch/cabling repaired > 5. you do "pcp_attach_node ... 0" to attach node 0 > 6. there are some writes happening which go to node 0 only > 7. yo do "pcp_attach_node ... 0" to attach node 1 > 8. writes go to both nodes now, but node 1 does not contain some data now > > > There is a workaround: stop pgpool, remove its status file, start it again, > but that's not really it.
Why don't you do online recovery for node 1 after 8? This will guarantee node 0 and 1 are in sync. -- 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
