I’m looking for some information about whether PostGreSQL EDB can provide balance between nodes similarly to the way Oracle RAC does this.
AFAIK, it does not.
The closest question / answer combination I could find to this subject follows:
However, that question and its answers at the above link discuss failovers, not load balancing.
I've also reviewed the e-booklet here:
http://www.enterprisedb.com/postgres-plus-edb-blog/gary-carter/comparing-edb-postgres-and-oracle
The ol' internet and a search on serverfault.com have not given me much joy, so far. I keep coming up with generic guidelines or corporate leaflets (without detailed examples of load balancing behavior) on either product.
So, for any of you who might have used PostGreSQL EDB, does it provide load balancing among nodes in a similar way to Oracle RAC?
Oracle RAC is shared-storage clustering. PostgreSQL doesn't do that.
As far as I know neither does PPAS, EDB's product. I work for a competing vendor and I don't use their products routinely, but I'm pretty sure I would've heard if they'd added shared-storage clustering.
The best way to be sure is to ask EDB directly. They have forums, they don't really hang out here.
There are other products and tools that provide various load-balancing, sharding and distribution options for PostgreSQL. Look into Postgres-XL, Citus, BDR, PgPool-II, EDB's failover manager, AWS Redshift, EDB's xDB, etc. All have advantages and disadvantages. None use the same model as Oracle RAC.
Shared-storage clustering is in my opinion not great anyway. It places a huge amount of reliance on a SAN, and its performance scaling is mediocre at best. Most PostgreSQL clustering work is focusing on replication based clustering with query routing and scatter/gather querying, sharding, distributed lock management/snapshot management/transaction management, etc. But then, I work on a replication based clustering solution (BDR) so I would say that.