Simply by larger sizes of compressed blocks, which are limited to page size in Postgres, and by improving the data locality by sorting, which is inherent for LSM-trees.
But if you want higher compression, you need to consider column-oriented DBMS, such as ClickHouse[1]. They are unbeatable in terms of data compression.
But if you want higher compression, you need to consider column-oriented DBMS, such as ClickHouse[1]. They are unbeatable in terms of data compression.
[1] https://github.com/ClickHouse/ClickHouse
Disclaimer: I'm a developer of ClickHouse.