Database Reference
In-Depth Information
With Slony 1.2, all replicated tables got locked with every
EXECUTE
SCRIPT
call, even if they
were in different replication sets. With Slony 2.0, locking is more relaxed, though this means it
is possible to use too little locking and cause yourself errors.
There's more...
Slony support in available through pgAdmin and phppgadmin GUIs, though Slony management
is probably too complex to make sense to control it through that route. Opinions will no doubt
differ on that point.
See also
For more information visit the following URL:
http://slony.info
Load balancing with pgpool-II 3.0
Pgpool-II is middleware that can perform the following major functions:
F
Connection pooling
F
Load balancing
F
Replication management
F
Parallel query
The only aspect of pgpool we cover here is load-balancing mode, which is designed to work
with the other forms of replication discussed in this chapter. Pgpool is actively developed and
contains many new features for PostgreSQL 9.0. Load balancing mode allows an application
to connect to pgpool once, and then spread certain kinds of work across multiple nodes. As
a result, it is possible to use pgpool with an existing application with minimal changes. There
are other ways of load balancing across multiple servers, though those utilize features of non-
PostgreSQL related software, so aren't covered here.
Getting ready
Before we use pgpool, we need to understand how the load balancing works, and whether it
will act as we would like.
