Distributed hypertables extend regular hypertables with the ability to store data chunks across multiple data nodes for better scale-out performance. Prior to creating a distributed hypertable, however, TimescaleDB must be set up for multi-node usage.
In most cases, using a distributed hypertable is similar to using a regular hypertable, including inserting, querying, and altering it. Thus, for basic usage, please review the documentation for regular hypertables.
For inserts and queries, however, a distributed hypertable has unique performance characteristics and there are also additional limitations due to its distributed nature. For instance, query performance is heavily dependent on the ability to push down work to data nodes, which in turn ties into how data is partitioned across the nodes. If it is not possible to push down computations, or the query does not involve many data nodes, the query performance of a distributed hypertable will likely be worse than that of a regular hypertable due to the additional network overhead.
Note, also, that distributed hypertables can live alongside non-distributed tables and other objects; in fact, no objects are distributed by default. Interactions between distributed hypertables and non-distributed objects might not have the expected behavior. For instance, setting permissions on a distributed hypertable only works if the roles involved exist identically on all data nodes. Further, joins between a local table and a distributed hypertable requires fetching the raw data from data nodes and performing the join locally.
Found an issue on this page?Report an issue!