Release 2.28.0

[timescale-automation]

2.28.0 (2026-06-16)

This release contains performance improvements and bug fixes since the 2.27.2 release. We recommend that you upgrade at the next available opportunity.

Highlighted features in TimescaleDB v2.28.0

• Faster first() and last() queries on compressed data. TimescaleDB derives first(value, time) and last(value, time) aggregates straight from the columnstore's batch metadata, skipping batch decompression entirely. For the "latest reading per series" lookups that time-series workloads run constantly, that means meaningfully faster recency queries with no changes to your SQL queries.
• Lighter, less disruptive continuous aggregate refreshes. refresh_continuous_aggregate() can now run incrementally in batches — the same behavior refresh policies already use — enabling breaking large manual refreshes into smaller chunks (tunable via buckets_per_batch, max_batches_per_execution, and refresh_newest_first) instead of one heavy operation. Refreshes also now take a lighter lock while processing the invalidation log, so they no longer block unrelated concurrent operations on the same continuous aggregate, improving behavior for concurrent workloads.
• Vectorized execution now covers CASE expressions. TimescaleDB's columnar executor can now evaluate CASE ... WHEN expressions directly on compressed data, so queries using conditional logic stay on the fast vectorized path instead of falling back to slower row-by-row decompression. This speeds up a common pattern — conditional aggregations and computed columns over compressed history — with no query changes needed.
• Add new aggregations to a continuous aggregate without rebuilding it. You can now run ALTER MATERIALIZED VIEW <cagg> ADD COLUMN <name> <type> GENERATED ALWAYS AS (<aggregate>) STORED to add a new computed aggregate to an existing continuous aggregate in place — no more dropping and recreating the whole aggregate just to track one more metric. New data populates the column going forward, letting your rollups evolve alongside your application. (Existing rows start as NULL; a forced refresh backfills them when you need historical values.)

Deprecation Notice: PostgreSQL 15 Support
This release marks the final minor version of TimescaleDB that will support PostgreSQL 15. Starting with our next release, version 2.29.0, we will officially drop support for Postgres 15, and only support Postgres 16, 17, and 18; however, all future patch releases within the current 2.28 version cycle will continue to fully support it. We recommend planning your PostgreSQL upgrades accordingly to ensure a smooth transition.

Deprecation Notice: chunk_constraint Catalog Table
Please note that the _timescaledb_catalog.chunk_constraint table has been dropped and temporarily replaced by a view, which introduces a change to the underlying objects while maintaining current query behavior. However, this compatibility view will be completely removed in a future release. To ensure your queries remain compatible moving forward, we strongly advise transitioning to the stable contracts provided by our informational views.

Backward-Incompatible Changes

• #9934 Remove adaptive chunking

Features

• #4054 Support ANALYZE and VACUUM on continuous aggregates by redirecting to the underlying materialization hypertable
• #9125 Increase the parallelism of SELECT queries over compressed hypertables to approximately match the uncompressed data size
• #9410 Mark hypertable and chunk as user catalog tables
• #9416 Support some forms of CASE expression in columnar aggregation and grouping
• #9580 Add first / last sparse indexes to compression
• #9784 Use first / last sparse index for orderby metadata on new compressed chunks
• #9668 Allow database owner to configure hypertables and policies
• #9701 Relax lock during continuous aggregate invalidation log processing
• #9730 Add in-memory observability for compressed chunks
• #9735 Improve GapFill row count estimate
• #9821 Allow subquery results which are exec params as GapFill arguments
• #9825 Support ADD COLUMN on continuous aggregates
• #9842 Suppress continuous aggregate invalidation tracking during bulk loads
• #9878 Remove chunk_constraint catalog tracking for foreign keys
• #9893 Remove chunk_constraint catalog tracking for non-dimensional constraints
• #9903 Incremental refresh for refresh_continuous_aggregate()
• #9915 Remove _timescaledb_catalog.chunk_constraint table
• #9938 Add rebuild_sparse_index function
• #9964 Add a function to lock OSM chunk's dimension slice
• #9980 Support first/last(value, time) in ColumnarIndexScan

Bugfixes

• #9708 Guard time bucket parameter handling against bad input
• #9745 Check constraints when adding unique constraints to chunks
• #9890 Fix incremental refresh batch boundaries to align with variable-width buckets and start only where a chunk and an invalidation overlap
• #9914 Fix use-after-free in segmentwise recompression
• #9929 Fix background jobs being bumped in the queue forever and never running
• #9955 Fix wrong results when using Batch Sorted Merge with no first-last index on a non-leading order by column
• #9967 Block upgrade after downgrade with first/last indexes present
• #9976 Fix wrong results when comparing a date column to a timestamptz value
• #9977 Fix COPY WHERE into a hypertable with dropped columns
• #9981 Fix set-returning functions in the sort key of ColumnarScan
• #9982 Reject ALTER TABLE ... INHERIT when the parent is a hypertable
• #9984 Fix handling of NOT VALID NOT NULL constraint for query optimization
• #9986 Handle MERGE WHEN NOT MATCHED BY SOURCE on hypertables
• #9988 Fix time_bucket_gapfill function detection
• #10003 Block unsafe updates of unique columns on compressed chunks
• #10024 Fix approximate_row_count handling of Infinity
• #10025 Fix rename on compressed continuous aggregates
• #10026 Fix chunk skipping near PG_INT64_MAX

New Settings

• skip_cagg_invalidation: skip continuous aggregate invalidation tracking for DML and DDL in the current session/transaction. Off by default.
• stats_max_chunks: set the per-database compressed chunk statistics cache capacity. Defaults to 1024 chunks; set to 0 to disable the feature.

Thanks

• @Fabian-2596 for suggesting more accurate GapFill row count estimate
• @otjdiepluong for fixing spelling mistakes in timescaledb source code comments
• @scimad and @Nosfistis for suggesting expanding coverage for gapfill arguments

[svenklemm]

Needs to mention this is last version with PG15 support

[atovpeko]

One nit