2025 Changelog

#### Build/Testing/Packaging Improvement[​](#buildtestingpackaging-improvement-5 "Direct link to Build/Testing/Packaging Improvement")

- Build a minimal C library (10 KB) for the ClickHouse lexer. This is needed for [#80977](https://github.com/ClickHouse/ClickHouse/issues/80977). [#81347](https://github.com/ClickHouse/ClickHouse/pull/81347) ([Alexey Milovidov](https://github.com/alexey-milovidov)). Add test for standalone lexer, add test tag `fasttest-only`. [#82472](https://github.com/ClickHouse/ClickHouse/pull/82472) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
- Add a check for Nix submodule inputs. [#81691](https://github.com/ClickHouse/ClickHouse/pull/81691) ([Konstantin Bogdanov](https://github.com/thevar1able)).
- Fix a list of problems that can occur when trying to run integration tests on a localhost. [#82135](https://github.com/ClickHouse/ClickHouse/pull/82135) ([Oleg Doronin](https://github.com/dorooleg)).
- Compile SymbolIndex on Mac and FreeBSD. (But it will work only on ELF systems, Linux and FreeBSD). [#82347](https://github.com/ClickHouse/ClickHouse/pull/82347) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- Bumped Azure SDK to v1.15.0. [#82747](https://github.com/ClickHouse/ClickHouse/pull/82747) ([Smita Kulkarni](https://github.com/SmitaRKulkarni)).
- Add storage module from google-cloud-cpp to build system. [#82881](https://github.com/ClickHouse/ClickHouse/pull/82881) ([Pablo Marcos](https://github.com/pamarcos)).
- Change `Dockerfile.ubuntu` for clickhouse-server to fit requirements in Docker Official Library. [#83039](https://github.com/ClickHouse/ClickHouse/pull/83039) ([Mikhail f. Shiryaev](https://github.com/Felixoid)).
- A follow-up for [#83158](https://github.com/ClickHouse/ClickHouse/issues/83158) to fix uploading builds to `curl clickhouse.com`. [#83463](https://github.com/ClickHouse/ClickHouse/pull/83463) ([Mikhail f. Shiryaev](https://github.com/Felixoid)).
- Adding `busybox` binary and install tools in `clickhouse/clickhouse-server` and official `clickhouse` images. [#83735](https://github.com/ClickHouse/ClickHouse/pull/83735) ([Mikhail f. Shiryaev](https://github.com/Felixoid)).
- Added support for the `CLICKHOUSE_HOST` environment variable to specify the ClickHouse server host, aligning with existing `CLICKHOUSE_USER` and `CLICKHOUSE_PASSWORD` environment variables. This allows for easier configuration without modifying client or configuration files directly. [#83659](https://github.com/ClickHouse/ClickHouse/pull/83659) ([Doron David](https://github.com/dorki)).

### ClickHouse release 25.6, 2025-06-26[​](#256 "Direct link to ClickHouse release 25.6, 2025-06-26")

#### Backward Incompatible Change[​](#backward-incompatible-change-6 "Direct link to Backward Incompatible Change")

- Previously, function `countMatches` would stop counting at the first empty match even if the pattern accepts it. To overcome this issue, `countMatches` now continues execution by advancing by a single character when an empty match occurs. Users who like to retain the old behavior can enable setting `count_matches_stop_at_empty_match`. [#81676](https://github.com/ClickHouse/ClickHouse/pull/81676) ([Elmi Ahmadov](https://github.com/ahmadov)).
- Minor: Force `backup_threads` and `restore_threads` server settings to be non zero. [#80224](https://github.com/ClickHouse/ClickHouse/pull/80224) ([Raúl Marín](https://github.com/Algunenano)).
- Minor: Fix `bitNot` for `String` will return a zero-terminated string in the internal memory representation. This should not affect any user visible behavior, however the author wanted to highlight this change. [#80791](https://github.com/ClickHouse/ClickHouse/pull/80791) ([Azat Khuzhin](https://github.com/azat)).

#### New Feature[​](#new-feature-6 "Direct link to New Feature")