This release contains performance improvements and bug fixes since the 2.20.3 release. We recommend that you upgrade at the next available opportunity.

Highlighted features in TimescaleDB v2.21.0

• The attach & detach chunks feature allows manually adding or removing chunks from a hypertable with uncompressed chunks, similar to PostgreSQL’s partition management.
• Continued improvement of backfilling into the columnstore, achieving up to 2.5x speedup for constrained tables, by introducing caching logic that boosts throughput for writes to compressed chunks, bringing INSERT performance close to that of uncompressed chunks.
• Optimized DELETE operations on the columstore through batch-level deletions of non-segmentby keys in the filter condition, greatly improving performance to up to 42x faster in some cases, as well as reducing bloat, and lowering resource usage.
• The heavy lock taken in Continuous Aggregate refresh was relaxed, enabling concurrent refreshes for non-overlapping ranges and eliminating the need for complex customer workarounds.
• [tech preview] Direct Compress is an innovative TimescaleDB feature that improves high-volume data ingestion by compressing data in memory and writing it directly to disk, reducing I/O overhead, eliminating dependency on background compression jobs, and significantly boosting insert performance.

Sunsetting of the hypercore access method We made the decision to deprecate hypercore access method (TAM) with the 2.21.0 release. It was an experiment, which did not show the signals we hoped for and will be sunsetted in TimescaleDB 2.22.0, scheduled for September 2025. Upgrading to 2.22.0 and higher will be blocked if TAM is still in use. Since TAM’s inception in 2.18.0, we learned that btrees were not the right architecture. The recent advancements in the columnstore—such as more performant backfilling, SkipScan, adding check constraints, and faster point queries—put the columnstore close to or on par with TAM without the storage from the additional index. We apologize for the inconvenience this action potentially causes and are here to assist you during the migration process.

Migration path

do $$
declare   
   relid regclass;
begin
   for relid in
       select cl.oid from pg_class cl
       join pg_am am on (am.oid = cl.relam)
       where am.amname = 'hypercore'
   loop
       raise notice 'converting % to heap', relid::regclass;
       execute format('alter table %s set access method heap', relid);
   end loop;
end
$$;

Features

• #8081 Use JSON error code for job configuration parsing
• #8100 Support splitting compressed chunks
• #8131 Add policy to process hypertable invalidations
• #8141 Add function to process hypertable invalidations
• #8165 Reindex recompressed chunks in compression policy
• #8178 Add columnstore option to CREATE TABLE WITH
• #8179 Implement direct DELETE on non-segmentby columns
• #8182 Cache information for repeated upserts into the same compressed chunk
• #8187 Allow concurrent Continuous Aggregate refreshes
• #8191 Add option to not process hypertable invalidations
• #8196 Show deprecation warning for TAM
• #8208 Use NULL compression for bool batches with all null values like the other compression algorithms
• #8223 Support for attach/detach chunk
• #8265 Set incremental Continous Aggregate refresh policy on by default
• #8274 Allow creating concurrent continuous aggregate refresh policies
• #8314 Add support for timescaledb_lake in loader
• #8209 Add experimental support for Direct Compress of COPY
• #8341 Allow quick migration from hypercore TAM to (columnstore) heap

Bugfixes

• #8153 Restoring a database having NULL compressed data
• #8164 Check columns when creating new chunk from table
• #8294 The "vectorized predicate called for a null value" error for WHERE conditions like x = any(null::int[]).
• #8307 Fix missing catalog entries for bool and null compression in fresh installations
• #8323 Fix DML issue with expression indexes and BHS

GUCs

• enable_direct_compress_copy: Enable experimental support for direct compression during COPY, default: off
• enable_direct_compress_copy_sort_batches: Enable batch sorting during direct compress COPY, default: on
• enable_direct_compress_copy_client_sorted: Correct handling of data sorting by the user is required for this option, default: off

This release contains bug fixes since the 2.20.2 release. We recommend that you upgrade at the next available opportunity.

Bugfixes

• #8107 Adjust SkipScan cost for quals needing full scan of indexed data.
• #8211 Fixed dump and restore when chunk skipping is enabled.
• #8216 Fix for dropped quals bug in SkipScan.
• #8230 Fix for inserting into compressed data when vectorised check is not available.
• #8236 Fixed the snapshot handling in background workers.

Thanks

• @ikaakkola for reporting that SkipScan is slow when non-index quals do not match any tuples.

This release contains bug fixes since the 2.20.1 release. We recommend that you upgrade at the next available opportunity.

Bugfixes

• https://github.com/timescale/timescaledb/pull/8202 Fix NULL compression handling for vectorized constraint checking

This release contains performance improvements and bug fixes since the 2.20.0 release. We recommend that you upgrade at the next available opportunity.

Features

• #8145 Log only if compression ratio warnings are enabled

Bugfixes

• #7292 Intermittent "could not find pathkey item to sort" error when grouping or ordering by a time_bucket of an equality join variable.
• #8126 Allow setting bgw_log_level to FATAL and ERROR
• #8151 Treat null equal to null for merged Continous Aggregate refresh
• #8153 Restoring a database having NULL compressed data
• #8162 Fix setting compress_chunk_interval on continuous aggregates
• #8163 Fix gapfill crash with locf NULL values treated as missing
• #8171 Disable decompression limit during continuous aggregate refresh

Thanks

• @bobozaur, @kvc0, @ChadMoran, @PaddyKe for reporting the pathkey error.
• @jlordiales for reporting an issue with setting compress_chunk_interval for continuous aggregates
• @svanharmelen, @cmdjulian, @etaMS20 for reporting time_bucket_gapfill with locf crash when NULL values are treated as missing

This release contains performance improvements and bug fixes since the 2.19.3 release. We recommend that you upgrade at the next available opportunity.

Highlighted features in TimescaleDB v2.20.0

• The columnstore now leverages bloom filters to deliver up to 6x faster point queries on columns with high cardinality values, such as UUIDs.
• Major improvements to the columnstores' backfill process enable UPSERTS with strict constraints to execute up to 10x faster.
• SkipScan is now supported in the columnstore, including for DISTINCT queries. This enhancement leads to dramatic query performance improvements of 2000x to 2500x, especially for selective queries.
• SIMD vectorization for the bool data type is now enabled by default. This change results in a 30–45% increase in performance for analytical queries with bool clauses on the columnstore.
• Continuous aggregates now include experimental support for window functions and non-immutable functions, extending the analytics use cases they can solve.
• Several quality-of-life improvements have been introduced: job names for continuous aggregates are now more descriptive, you can assign custom names to them, and it is now possible to add unique constraints along with ADD COLUMN operations in the columnstore.
• Improved management and optimization of chunks with the ability to split large uncompressed chunks at a specified point in time using the split_chunk function. This new function complements the existing merge_chunk function that can be used to merge two small chunks into one larger chunk.
• Enhancements to the default behavior of the columnstore now provide better automatic assessments of segment by and order by columns, reducing the need for manual configuration and simplifying initial setup.

PostgreSQL 14 support removal announcement

Following the deprecation announcement for PostgreSQL 14 in TimescaleDB v2.19.0, PostgreSQL 14 is no longer supported in TimescaleDB v2.20.0. The currently supported PostgreSQL major versions are 15, 16, and 17.

Features

• #7638 Bloom filter sparse indexes for compressed columns. Can be disabled with the GUC timescaledb.enable_sparse_index_bloom
• #7756 Add warning for poor compression ratio
• #7762 Speed up the queries that use minmax sparse indexes on compressed tables by changing the index TOAST storage type to MAIN. This applies to newly compressed chunks
• #7785 Do DELETE instead of TRUNCATE when locks aren't acquired
• #7852 Allow creating foreign key constraints on compressed tables
• #7854 Remove support for PG14
• #7864 Allow adding CHECK constraints to compressed chunks
• #7868 Allow adding columns with CHECK constraints to compressed chunks
• #7874 Support for SkipScan for distinct aggregates over the same column
• #7877 Remove blocker for unique constraints with ADD COLUMN
• #7878 Don't block non-immutable functions in continuous aggregates
• #7880 Add experimental support for window functions in continuous aggregates
• #7899 Vectorized decompression and filtering for boolean columns
• #7915 New option refresh_newest_first to continuous aggregate refresh policy API
• #7917 Remove _timescaledb_functions.create_chunk_table function
• #7929 Add CREATE TABLE ... WITH API for creating hypertables
• #7946 Add support for splitting a chunk
• #7958 Allow custom names for jobs
• #7972 Add vectorized filtering for constraint checking while backfilling into compressed chunks
• #7976 Include continuous aggregate name in jobs informational view
• #7977 Replace references to compression with columnstore
• #7981 Add columnstore as alias for enable_columnstore in ALTER TABLE
• #7983 Support for SkipScan over compressed data
• #7991 Improves default segmentby options
• #7992 Add API into hypertable invalidation log
• #8000 Add primary dimension info to information schema
• #8005 Support ALTER TABLE SET (timescaledb.chunk_time_interval='1 day')
• #8012 Add event triggers support on chunk creation
• #8014 Enable bool compression by default by setting timescaledb.enable_bool_compression=true. Note: for downgrading to 2.18 or earlier version, use this downgrade script
• #8018 Add spin-lock during recompression on unique constraints
• #8026 Allow WHERE conditions that use nonvolatile functions to be pushed down to the compressed scan level. For example, conditions like time > now(), where time is a columnstore orderby column, will evaluate now() and use the sparse index on time to filter out the entire compressed batches that cannot contain matching rows.
• #8027 Add materialization invalidations API
• #8047 Support SkipScan for SELECT DISTINCT with multiple distincts when all but one distinct is pinned
• #8115 Add batch size limiting during compression

Bugfixes

• #7862 Release cache pin when checking for NOT NULL
• #7909 Update compression stats when merging chunks
• #7928 Don't create a hypertable for implicitly published tables
• #7982 Fix crash in batch sort merge over eligible expressions
• #8008 Fix compression policy error message that shows number of successes
• #8031 Fix reporting of deleted tuples for direct batch delete
• #8033 Skip default segmentby if orderby is explicitly set
• #8061 Ensure settings for a compressed relation are found
• #7515 Add missing lock to Constraint-aware append
• #8067 Make sure hypercore TAM parent is vacuumed
• #8074 Fix memory leak in row compressor flush
• #8099 Block chunk merging on multi-dimensional hypertables
• #8106 Fix segfault when adding unique compression indexes to compressed chunks
• #8127 Read bit-packed version of booleans

GUCs

• timescaledb.enable_sparse_index_bloom: Enable creation of the bloom1 sparse index on compressed chunks; Default: ON
• timescaledb.compress_truncate_behaviour: Defines how truncate behaves at the end of compression; Default: truncate_only
• timescaledb.enable_compression_ratio_warnings: Enable warnings for poor compression ratio; Default: ON
• timescaledb.enable_event_triggers: Enable event triggers for chunks creation; Default: OFF
• timescaledb.enable_cagg_window_functions: Enable window functions in continuous aggregates; Default: OFF

Thanks

• @arajkumar for reporting that implicitly published tables were still able to create hypertables
• @thotokraa for reporting an issue with unique expression indexes on compressed chunks

This release contains bug fixes since the 2.19.2 release. We recommend that you upgrade at the next available opportunity.

Bug fixes

• #7893 Don't capture hard errors in with-clause parser
• #7903 Don't capture hard errors for old cagg format
• #7912 Don't capture errors estimating time max spread
• #7910 Fix not using SkipScan over one chunk
• #7913 Allow TAM chunk creation as non-owner
• #7935 Fix TAM segfault on DELETE using segmentby column
• #7954 Allow scheduler restarts to be disabled
• #7964 Crash when grouping by multiple columns of a compressed table, one of which is a UUID segmentby column.

This release contains bug fixes since the 2.19.1 release. We recommend that you upgrade at the next available opportunity.

Features

• #7923 Add a GUC to set a compression batch size limit

Bugfixes

• #7911 Don't create a Hypertable for published tables
• #7902 Fix crash in VectorAgg plan code

GUCs

• compression_batch_size_limit: set batch size limit, default: 1000

Thanks

• @soedirgo for reporting that published tables don't get dropped when they have a hypertable*

This release contains bug fixes since the 2.19.0 release. We recommend that you upgrade at the next available opportunity.

Bugfixes

• #7816 Fix ORDER BY for direct queries on partial chunks
• #7834 Avoid unnecessary scheduler restarts
• #7837 Ignore frozen chunks in compression policy
• #7850 Add is_current_xact_tuple to Arrow TTS
• #7890 Flush error state before doing anything else

Thanks

• @bjornuppeke for reporting a problem with INSERT INTO ... ON CONFLICT DO NOTHING on compressed chunks
• @kav23alex for reporting a segmentation fault on ALTER TABLE with DEFAULT

This release contains performance improvements and bug fixes since the 2.18.2 release. We recommend that you upgrade at the next available opportunity.

• Improved concurrency of INSERT, UPDATE and DELETE operations on the columnstore by no longer blocking DML statements during the recompression of a chunk.
• Improved system performance during Continuous Aggregates refreshes by breaking them into smaller batches which reduces systems pressure and minimizes the risk of spilling to disk.
• Faster and more up-to-date results for queries against Continuous Aggregates by materializing the most recent data first (vs old data first in prior versions).
• Faster analytical queries with SIMD vectorization of aggregations over text columns and group by over multiple column
• Enable optimizing chunk size for faster query performance on the columnstore by adding support for merging columnstore chunks to the merge_chunk API.

Deprecation warning

This is the last minor release supporting PostgreSQL 14. Starting with the minor version of TimescaleDB only Postgres 15, 16 and 17 will be supported.

Downgrading of 2.19.0

This release introduces custom bool compression, if you enable this feature via the enable_bool_compression and must downgrade to a previous, please use the following script to convert the columns back to their previous state. TimescaleDB versions prior to 2.19.0 do not know how to handle this new type.

Features

• #7586 Vectorized aggregation with grouping by a single text column.
• #7632 Optimize recompression for chunks without segmentby
• #7655 Support vectorized aggregation on Hypercore TAM
• #7669 Add support for merging compressed chunks
• #7701 Implement a custom compression algorithm for bool columns. It is experimental and can undergo backwards-incompatible changes. For testing, enable it using timescaledb.enable_bool_compression = on.
• #7707 Support ALTER COLUMN SET NOT NULL on compressed chunks
• #7765 Allow tsdb as alias for timescaledb in WITH and SET clauses
• #7786 Show warning for inefficient compress_chunk_time_interval configuration
• #7788 Add callback to mem_guard for background workers
• #7789 Do not recompress segmentwise when default order by is empty
• #7790 Add configurable Incremental CAgg Refresh Policy

Bugfixes

• #7665 Block merging of frozen chunks
• #7673 Don't abort additional INSERTs when hitting first conflict
• #7714 Fixes a wrong result when compressed NULL values were confused with default values. This happened in very special circumstances with alter table added a new column with a default value, an update and compression in a very particular order.
• #7747 Block TAM rewrites with incompatible GUC setting
• #7748 Crash in the segmentwise recompression
• #7764 Fix compression settings handling in Hypercore TAM
• #7768 Remove costing index scan of hypertable parent
• #7799 Handle DEFAULT table access name in ALTER TABLE

GUCs

• enable_bool_compression: enable the BOOL compression algorithm, default: OFF
• enable_exclusive_locking_recompression: enable exclusive locking during recompression (legacy mode), default: OFF

Thanks

• @bjornuppeke for reporting a problem with INSERT INTO ... ON CONFLICT DO NOTHING on compressed chunks
• @kav23alex for reporting a segmentation fault on ALTER TABLE with DEFAULT

This release contains performance improvements and bug fixes since the 2.18.1 release. We recommend that you upgrade at the next available opportunity.

Bugfixes

• #7686 Potential wrong aggregation result when using vectorized aggregation with hash grouping in reverse order
• #7694 Fix ExplainHook breaking call chain
• #7695 Block dropping internal compressed chunks with drop_chunk()
• #7711 License error when using hypercore handler
• #7712 Respect other extensions' ExecutorStart hooks

Thanks

• @davidmehren and @jflambert for reporting an issue with extension hooks
• @jflambert for reporting a bug with license errors shown in autovacuum