2025 Changelog

- `EXPLAIN SYNTAX` now uses a new analyzer. It returns AST built from the query tree. Added option `query_tree_passes` to control the number of passes to executed before converting query tree to the AST. [#74536](https://github.com/ClickHouse/ClickHouse/pull/74536) ([Vladimir Cherkasov](https://github.com/vdimir)).
- Implement flattened serialization for Dynamic and JSON in Native format that allows to serialize/deserialize Dynamic and JSON data without special structures like shared variant for Dynamic and shared data for JSON. This serialization can be enabled by setting `output_format_native_use_flattened_dynamic_and_json_serialization`. This serialization can be used for easier support for Dynamic and JSON in TCP protocol in clients in different languages. [#80499](https://github.com/ClickHouse/ClickHouse/pull/80499) ([Pavel Kruglov](https://github.com/Avogar)).
- Refresh `S3` credentials after error `AuthenticationRequired`. [#77353](https://github.com/ClickHouse/ClickHouse/pull/77353) ([Vitaly Baranov](https://github.com/vitlibar)).
- Added dictionary metrics to `system.asynchronous_metrics` - `DictionaryMaxUpdateDelay` - the maximum delay (in seconds) of dictionary update. - `DictionaryTotalFailedUpdates` - the number of errors since last successful loading in all dictionaries. [#78175](https://github.com/ClickHouse/ClickHouse/pull/78175) ([Vlad](https://github.com/codeworse)).
- Add a warning about databases that were potentially created to save broken tables. [#78841](https://github.com/ClickHouse/ClickHouse/pull/78841) ([János Benjamin Antal](https://github.com/antaljanosbenjamin)).
- Add `_time` virtual column in `S3Queue`, `AzureQueue` engine. [#78926](https://github.com/ClickHouse/ClickHouse/pull/78926) ([Anton Ivashkin](https://github.com/ianton-ru)).
- Make settings controlling connection drop on overloaded CPU hot-reloadable. [#79052](https://github.com/ClickHouse/ClickHouse/pull/79052) ([Alexey Katsman](https://github.com/alexkats)).
- Add container prefix to data paths reported in system.tables for plain disks in Azure blob storage, making reporting consistent with S3 and GCP. [#79241](https://github.com/ClickHouse/ClickHouse/pull/79241) ([Julia Kartseva](https://github.com/jkartseva)).
- Now, clickhouse-client and local also accept query parameters as `param-<name>` (dash) along with `param_<name>` (underscore). This closes [#63093](https://github.com/ClickHouse/ClickHouse/issues/63093). [#79429](https://github.com/ClickHouse/ClickHouse/pull/79429) ([Engel Danila](https://github.com/aaaengel)).
- Detailed warning msg for bandwidth discount when copying data from local to remote S3 with checksum enabled. [#79464](https://github.com/ClickHouse/ClickHouse/pull/79464) ([VicoWu](https://github.com/VicoWu)).
- Previously, when `input_format_parquet_max_block_size = 0` (an invalid value) ClickHouse would stuck. Now this behaviour is fixed. This closes [#79394](https://github.com/ClickHouse/ClickHouse/issues/79394). [#79601](https://github.com/ClickHouse/ClickHouse/pull/79601) ([abashkeev](https://github.com/abashkeev)).
- Add `throw_on_error` setting for `startup_scripts`: when `throw_on_error` is true, the server will not start unless all queries complete successfully. By default, `throw_on_error` is false, preserving the previous behavior. [#79732](https://github.com/ClickHouse/ClickHouse/pull/79732) ([Aleksandr Musorin](https://github.com/AVMusorin)).
- Allow to add `http_response_headers` in `http_handlers` of any kind. [#79975](https://github.com/ClickHouse/ClickHouse/pull/79975) ([Andrey Zvonov](https://github.com/zvonand)).
- Function `reverse` now supports `Tuple` data type. Closes [#80053](https://github.com/ClickHouse/ClickHouse/issues/80053). [#80083](https://github.com/ClickHouse/ClickHouse/pull/80083) ([flynn](https://github.com/ucasfl)).
- Resolve [#75817](https://github.com/ClickHouse/ClickHouse/issues/75817): allow getting `auxiliary_zookeepers` data from `system.zookeeper` table. [#80146](https://github.com/ClickHouse/ClickHouse/pull/80146) ([Nikolay Govorov](https://github.com/mrdimidium)).
- Add asynchronous metrics about the server's TCP sockets. This improves the observability. Closes [#80187](https://github.com/ClickHouse/ClickHouse/issues/80187). [#80188](https://github.com/ClickHouse/ClickHouse/pull/80188) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- Support `anyLast_respect_nulls` and `any_respect_nulls` as a `SimpleAggregateFunction`. [#80219](https://github.com/ClickHouse/ClickHouse/pull/80219) ([Diskein](https://github.com/Diskein)).
- Remove unnecessary call `adjustCreateQueryForBackup` for replicated databases. [#80282](https://github.com/ClickHouse/ClickHouse/pull/80282) ([Vitaly Baranov](https://github.com/vitlibar)).
- Allow extra options (that go after `--` like `-- --config.value='abc'`) in `clickhouse-local` without the equality sign. Closes [#80292](https://github.com/ClickHouse/ClickHouse/issues/80292). [#80293](https://github.com/ClickHouse/ClickHouse/pull/80293) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- Highlight metacharacters in `SHOW ... LIKE` queries. This closes [#80275](https://github.com/ClickHouse/ClickHouse/issues/80275). [#80297](https://github.com/ClickHouse/ClickHouse/pull/80297) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- Make SQL UDF persistent in `clickhouse-local`. The previously created function will be loaded at startup. This closes [#80085](https://github.com/ClickHouse/ClickHouse/issues/80085). [#80300](https://github.com/ClickHouse/ClickHouse/pull/80300) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- Fix description in explain plan for preliminary DISTINCT step. [#80330](https://github.com/ClickHouse/ClickHouse/pull/80330) ([UnamedRus](https://github.com/UnamedRus)).
- Allow to use named collections in ODBC/JDBC. [#80334](https://github.com/ClickHouse/ClickHouse/pull/80334) ([Andrey Zvonov](https://github.com/zvonand)).
- Metrics for number of readonly and broken disks. Indicator logs when DiskLocalCheckThread is started. [#80391](https://github.com/ClickHouse/ClickHouse/pull/80391) ([VicoWu](https://github.com/VicoWu)).
- Implement support for `s3_plain_rewritable` storage with projections. In previous versions, metadata objects in S3 referencing projections would not get updated when moved. Closes [#70258](https://github.com/ClickHouse/ClickHouse/issues/70258). [#80393](https://github.com/ClickHouse/ClickHouse/pull/80393) ([Sav](https://github.com/sberss)).
- The `SYSTEM UNFREEZE` command will not try to look up parts in readonly and write-once disks. This closes [#80430](https://github.com/ClickHouse/ClickHouse/issues/80430). [#80432](https://github.com/ClickHouse/ClickHouse/pull/80432) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- Lowered the log level of merged parts messages. [#80476](https://github.com/ClickHouse/ClickHouse/pull/80476) ([Hans Krutzer](https://github.com/hkrutzer)).
- Change the default behavior of partition pruning for Iceberg tables. [#80583](https://github.com/ClickHouse/ClickHouse/pull/80583) ([Melvyn Peignon](https://github.com/melvynator)).
- Add two new ProfileEvents for index search algorithm observability: `IndexBinarySearchAlgorithm` and `IndexGenericExclusionSearchAlgorithm`. [#80679](https://github.com/ClickHouse/ClickHouse/pull/80679) ([Pablo Marcos](https://github.com/pamarcos)).
- Do not complain about unsupported `MADV_POPULATE_WRITE` for older kernels in logs (to avoid logs polluting). [#80704](https://github.com/ClickHouse/ClickHouse/pull/80704) ([Robert Schulze](https://github.com/rschu1ze)).
- Added support for `Date32` and `DateTime64` in `TTL` expressions. [#80710](https://github.com/ClickHouse/ClickHouse/pull/80710) ([Andrey Zvonov](https://github.com/zvonand)).
- Adjust compatibility values for `max_merge_delayed_streams_for_parallel_write`. [#80760](https://github.com/ClickHouse/ClickHouse/pull/80760) ([Azat Khuzhin](https://github.com/azat)).