While TimescaleDB generally offers capabilities that go beyond what
PostgreSQL offers, there are some limitations to using hypertables,
and, in particular, distributed hypertables. This section documents
the common limitations when using both regular and distributed
- Foreign key constraints referencing a hypertable are not supported.
- Time dimensions (columns) used for partitioning cannot have NULL
- Unique indexes must include all columns that are partitioning
UPDATE statements that move values between partitions (chunks) are
not supported. This includes upserts (
INSERT ... ON CONFLICT
Distributed hypertable limitations
All the limitations of regular hypertables also apply to distributed
hypertables. In addition, the following limitations apply specifically
to distributed hypertables:
- Distributed scheduling of background jobs is not supported. Background jobs
created on an access node are scheduled and executed on this access node
without distributing the jobs to data nodes.
- Continuous aggregates are only supported on the access node.
- Reordering chunks is not supported.
- Tablespaces cannot be attached to a distributed hypertable on the
access node. It is still possible attach tablespaces on data nodes.
- Roles and permissions are assumed to be consistent across the nodes
of a distributed database, but consistency is not enforced.
- Joins on data nodes are not supported. Joining a distributed
hypertable with another table requires the other table to reside on
the access node. This also limits the performance of joins on
- Tables referenced by foreign key constraints in a distributed
hypertable must be present on the access node and all data
nodes. This applies also to referenced values.
- Parallel-aware scans and appends are not supported.
- A consistent restore point for backup/restore across nodes is not
natively provided; care must be taken when restoring individual
backups to access and data nodes.
- Native replication limitations are described here.
- User defined functions have to be manually installed on the data nodes
so that the function definition is available on both access and data
nodes. This is particularly relevant for functions that are
Note that these limitations concern usage from the access node. Some
currently unsupported features might still work on individual data nodes,
but such usage is neither tested nor officially supported. Future versions
of TimescaleDB might remove some of these limitations.
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