Do the benchmarks for postgres utilize in memory columar store (IMCS)? What is the difference between postgres imcs and citus cstore_fdw? http://www.postgresql.org/message-id/52C59858.9090500@garret...
ICMS is a different implementation of a columnar store for PostgreSQL. I don't know it extremely well but my understanding is that it uses the PostgreSQL shared memory system to allocate memory for a columnar store. This columnar store is not queried via standard SQL commands but rather using a combination of a custom query language and some user defined functions.