Data tiering

TimescaleDB includes the ability to perform data tiering by moving chunks between PostgreSQL tablespaces. Tablespaces are locations on disk where PostgreSQL stores data files containing database objects, and each can be backed by a different class of storage. As data ages, you can add new tablespaces backed by a specified storage class and use the move_chunk API function to migrate data between these tablespaces.

For example, we can attach multiple tablespaces to a single hypertable; in the following example, we use two tablespaces:

1. Tablespace pg_default is backed by faster, more expensive storage (SSDs) and is meant for recent chunks that are being actively written to and regularly queried.
2. Tablespace history is backed by slower, less expensive storage (HDDs) and is meant for older chunks that are more rarely queried.

Taking a "data tiering" approach, as data ages, its corresponding chunks are moved from pg_default to history. This provides users with the ability to tradeoff storage performance for cost, and additional "tiers" of increasingly large/cheap/slow tablespaces may be employed when appropriate. Therefore, data tiering provides another mechanism, in addition to other TimescaleDB capabilities like compression and data retention, to help manage data storage costs.

Using multiple tablespaces can also yield I/O performance benefits. With data tiering, you can isolate large scans of historical data away from the continual read/write workload against recent data (in the default tablespace).