2025 Changelog

- Support writing multiple data files in Iceberg in a single insertion. Add new settings, `iceberg_insert_max_rows_in_data_file` and `iceberg_insert_max_bytes_in_data_file` to control the limits. [#86275](https://github.com/ClickHouse/ClickHouse/pull/86275) ([scanhex12](https://github.com/scanhex12)).
- Add rows/bytes limit for inserted data files in delta lake. Controlled by settings `delta_lake_insert_max_rows_in_data_file` and `delta_lake_insert_max_bytes_in_data_file`. [#86357](https://github.com/ClickHouse/ClickHouse/pull/86357) ([Kseniia Sumarokova](https://github.com/kssenii)).
- Support more types for partitions in Iceberg writes. This closes [#86206](https://github.com/ClickHouse/ClickHouse/issues/86206). [#86298](https://github.com/ClickHouse/ClickHouse/pull/86298) ([scanhex12](https://github.com/scanhex12)).
- Make S3 retry strategy configurable and make settings of S3 disk can be hot reload if change the config XML file. [#82642](https://github.com/ClickHouse/ClickHouse/pull/82642) ([RinChanNOW](https://github.com/RinChanNOWWW)).
- Improved S3(Azure)Queue table engine to allow it to survive zookeeper connection loss without potential duplicates. Requires enabling S3Queue setting `use_persistent_processing_nodes` (changeable by `ALTER TABLE MODIFY SETTING`). [#85995](https://github.com/ClickHouse/ClickHouse/pull/85995) ([Kseniia Sumarokova](https://github.com/kssenii)).
- You can use query parameters after `TO` when creating a materialized view, for example: `CREATE MATERIALIZED VIEW mv TO {to_table:Identifier} AS SELECT * FROM src_table`. [#84899](https://github.com/ClickHouse/ClickHouse/pull/84899) ([Diskein](https://github.com/Diskein)).
- Give more clear instruction for users when incorrect settings are specified for the `Kafka2` table engine. [#83701](https://github.com/ClickHouse/ClickHouse/pull/83701) ([János Benjamin Antal](https://github.com/antaljanosbenjamin)).
- It's no longer possible to specify time zones for the `Time` type (it didn't make sense). [#84689](https://github.com/ClickHouse/ClickHouse/pull/84689) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).
- Simplified (and avoided some bugs) a logic related to parsing Time/Time64 in the `best_effort` mode. [#84730](https://github.com/ClickHouse/ClickHouse/pull/84730) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).
- Added `deltaLakeAzureCluster` function (similar to `deltaLakeAzure` for the cluster mode) and `deltaLakeS3Cluster` (alias to `deltaLakeCluster`) function. Resolves [#85358](https://github.com/ClickHouse/ClickHouse/issues/85358). [#85547](https://github.com/ClickHouse/ClickHouse/pull/85547) ([Smita Kulkarni](https://github.com/SmitaRKulkarni)).
- Apply `azure_max_single_part_copy_size` setting for normal copy operations in the same way as for backup. [#85767](https://github.com/ClickHouse/ClickHouse/pull/85767) ([Ilya Golshtein](https://github.com/ilejn)).
- Slow down S3 client threads on retryable errors in S3 Object Storage. This extends the previous setting `backup_slow_all_threads_after_retryable_s3_error` to S3 disks and renames it to the more general `s3_slow_all_threads_after_retryable_error`. [#85918](https://github.com/ClickHouse/ClickHouse/pull/85918) ([Julia Kartseva](https://github.com/jkartseva)).
- Mark settings allow\_experimental\_variant/dynamic/json and enable\_variant/dynamic/json as obsolete. Now all three types are enabled unconditionally. [#85934](https://github.com/ClickHouse/ClickHouse/pull/85934) ([Pavel Kruglov](https://github.com/Avogar)).
- Support filtering by complete URL string (`full_url` directive) in `http_handlers` (including schema and host:port). [#86155](https://github.com/ClickHouse/ClickHouse/pull/86155) ([Azat Khuzhin](https://github.com/azat)).
- Add a new setting, `allow_experimental_delta_lake_writes`. [#86180](https://github.com/ClickHouse/ClickHouse/pull/86180) ([Kseniia Sumarokova](https://github.com/kssenii)).
- Fix detection of systemd in init.d script (fixes "Install packages" check). [#86187](https://github.com/ClickHouse/ClickHouse/pull/86187) ([Azat Khuzhin](https://github.com/azat)).
- Add a new `startup_scripts_failure_reason` dimensional metric. This metric is needed to distinguish between different error types that result in failing startup scripts. In particular, for alerting purposes, we need to distinguish between transient (e.g., `MEMORY_LIMIT_EXCEEDED` or `KEEPER_EXCEPTION`) and non-transient errors. [#86202](https://github.com/ClickHouse/ClickHouse/pull/86202) ([Miсhael Stetsyuk](https://github.com/mstetsyuk)).
- Allow to omit `identity` function for partition for Iceberg table. [#86314](https://github.com/ClickHouse/ClickHouse/pull/86314) ([scanhex12](https://github.com/scanhex12)).
- Add ability to enable JSON logging only for specific channel, for this set `logger.formatting.channel` to one of `syslog`/`console`/`errorlog`/`log`. [#86331](https://github.com/ClickHouse/ClickHouse/pull/86331) ([Azat Khuzhin](https://github.com/azat)).
- Allow using native numbers in `WHERE`. They are already allowed to be arguments of logical functions. This simplifies filter-push-down and move-to-prewhere optimizations. [#86390](https://github.com/ClickHouse/ClickHouse/pull/86390) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
- Fixed error in case of executing `SYSTEM DROP REPLICA` against a Catalog with corrupted metadata. [#86391](https://github.com/ClickHouse/ClickHouse/pull/86391) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
- Add extra retries for disk access check (`skip_access_check = 0`) in Azure because it may be provisioning access for quite a long time. [#86419](https://github.com/ClickHouse/ClickHouse/pull/86419) ([Alexander Tokmakov](https://github.com/tavplubix)).
- Make the staleness window in `timeSeries*()` functions left-open and right-closed. [#86588](https://github.com/ClickHouse/ClickHouse/pull/86588) ([Vitaly Baranov](https://github.com/vitlibar)).
- Add `FailedInternal*Query` profile events. [#86627](https://github.com/ClickHouse/ClickHouse/pull/86627) ([Shane Andrade](https://github.com/mauidude)).
- Fixes handling of users with a dot in the name when added via config file. [#86633](https://github.com/ClickHouse/ClickHouse/pull/86633) ([Mikhail Koviazin](https://github.com/mkmkme)).
- Add asynchronous metric for memory usage in queries (`QueriesMemoryUsage` and `QueriesPeakMemoryUsage`). [#86669](https://github.com/ClickHouse/ClickHouse/pull/86669) ([Azat Khuzhin](https://github.com/azat)).
- You can use `clickhouse-benchmark --precise` flag for more precise reporting of QPS and other per-interval metrics. It helps to get consistent QPS in case if durations of queries are comparable to the reporting interval `--delay D`. [#86684](https://github.com/ClickHouse/ClickHouse/pull/86684) ([Sergei Trifonov](https://github.com/serxa)).
- Make nice values of Linux threads configurable to assign some threads (merge/mutate, query, materialized view, zookeeper client) higher or lower priorities. [#86703](https://github.com/ClickHouse/ClickHouse/pull/86703) ([Miсhael Stetsyuk](https://github.com/mstetsyuk)).
- Fix misleading “specified upload does not exist” error, which occurs when the original exception is lost in multipart upload because of a race condition. [#86725](https://github.com/ClickHouse/ClickHouse/pull/86725) ([Julia Kartseva](https://github.com/jkartseva)).
- Limit query plan description in the `EXPLAIN` query. Do not calculate the description for queries other than `EXPLAIN`. Added a setting `query_plan_max_step_description_length`. [#86741](https://github.com/ClickHouse/ClickHouse/pull/86741) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
- Add ability to tune pending signals in attempt to overcome CANNOT\_CREATE\_TIMER (for query profilers, `query_profiler_real_time_period_ns`/`query_profiler_cpu_time_period_ns`). And also collect `SigQ` from the `/proc/self/status` for introspection (if `ProcessSignalQueueSize` is near to `ProcessSignalQueueLimit`, then you will likely get `CANNOT_CREATE_TIMER` errors). [#86760](https://github.com/ClickHouse/ClickHouse/pull/86760) ([Azat Khuzhin](https://github.com/azat)).