We have successfully deployed Postgres 9.3 with streaming replication (WAL replication). We currently have 2 slaves, the second slave being a cascaded slave from the first slave. Both slaves are hot-standby's with active read-only connections in use.
Due to load, we'd like to create a 3rd slave, with slightly different hardware specifications, and a different application using it as a read-only database in more of a Data Warehouse use-case. As it's for a different application, we'd like to optimize it specifically for that application, and improve performance by utilizing some additional indexes. For size and performances purposes, we'd rather not have those indexes on the master, or the other 2 slaves.
So my main question is, can we create different indexes on slaves for streaming replication, and if not, is there another data warehouse technique that I'm missing out on?