CFS enables page-level compression in Shardman. Compression can only be enabled for separate tablespaces. To compress a tablespace, you need to enable the compression option when creating this tablespace. For example:
CREATE TABLESPACE data LOCATION '/mnt/data-{rgid}' WITH (global, compression='zlib');
Now you can create tables and indexes in this tablespace or move existing table or index to it.
CREATE TABLE pgbench_branches (
bid integer NOT NULL PRIMARY KEY USING INDEX TABLESPACE data,
bbalance integer,
filler character(88)
)
WITH (distributed_by = 'bid') TABLESPACE data;
The cfs_compression_ratio() function returns the actual compression
ratio for all segments of the compressed relation. However, it returns
NaN for partitioned and foreign tables, so it works only for local
partitions of a sharded table.
Complete CFS documentation can be found here.