Pascal Cohen wrote: > Hello all > I am new to PgPool (and also Slony). > I am currently studying the way to ensure more availability but also > load balancing to reduce the load on a single DB whenever we would need it. > PgPool-II is very nice and is running well in the tests I did and the > way to integrate it with PgPool-HA seems nice. > But I am concerned with the replication between several DBs. > I can handle that in two ways: > First use PgPool only as a load balancer and rely on Slony for > replication or use PgPool as load balancer and replicator. > I would like to know what are the drawbacks and the advantages of each > solution. > > I would like also to get details on the PgPool replication behavior. > The simplest is probably a dummy example. > Let's say we have a master DB containing a table A and a transaction > updates one row in A. Table A in S is synchronized with M. > Let's say then that I have two connections that get the updated row in A. > > Using PgPool as load balancer between a Master M and a Slave S. I can > have the following situation (not necessary much probable but > technically possible): > Update of A in M. > First request on A goes on M. > Second request on A goes to S. > Slony performs synchro between M and S. > In that case my two requests may return different results. > > Can that situation occurs also with PgPool replication like: > PgPool sends update of A in M . > First request on A goes on M. > Second request on A goes to S. > PgPool sends update to S. > > My main concern is in fact that there can be transitional state where we > can get different data depending on the targeted DB choosing PgPool > replication or Slony replication. > > Am I right ? > > Hello again Can anybody help me ? Thanks
Regards Pascal _______________________________________________ Pgpool-general mailing list [email protected] http://pgfoundry.org/mailman/listinfo/pgpool-general
