v26.2 Changelog for Cloud

### System tables and monitoring[​](#system-tables-and-monitoring-improvements "Direct link to System tables and monitoring")

- Added `parts_postpone_reasons` column to `system.mutations` for improved diagnostics. [#92206](https://github.com/ClickHouse/ClickHouse/pull/92206) ([Shaohua Wang](https://github.com/tiandiwonder)).
- Added `creation` (implicit/explicit) column to `system.data_skipping_indices`. [#92378](https://github.com/ClickHouse/ClickHouse/pull/92378) ([Raúl Marín](https://github.com/Algunenano)).
- Running tasks are now reflected in `system.background_schedule_pool` and the corresponding log table. [#92587](https://github.com/ClickHouse/ClickHouse/pull/92587) ([Azat Khuzhin](https://github.com/azat)).
- Added `QueryNonInternal` metric to track the number of executing non-internal queries, helping monitor concurrency against the `max_concurrent_queries` limit. [#94284](https://github.com/ClickHouse/ClickHouse/pull/94284) ([Ashwath Singh](https://github.com/ashwath)).
- Added an asynchronous metric for the longest running merge elapsed time. [#94825](https://github.com/ClickHouse/ClickHouse/pull/94825) ([Raúl Marín](https://github.com/Algunenano)).
- Added `connection_address` and `connection_port` to `query_log` to reflect the physical connection (useful when connected through a proxy). [#95471](https://github.com/ClickHouse/ClickHouse/pull/95471) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
- Added more information to `system.crash_log`. [#94112](https://github.com/ClickHouse/ClickHouse/pull/94112) ([Miсhael Stetsyuk](https://github.com/mstetsyuk)).
- Added component name to `system.aggregated_zookeeper_log`. [#95882](https://github.com/ClickHouse/ClickHouse/pull/95882) ([Antonio Andelic](https://github.com/antonio2368)).
- Added `system.tokenizers` table showing all available tokenizers. [#96753](https://github.com/ClickHouse/ClickHouse/pull/96753) ([Robert Schulze](https://github.com/rschu1ze)).
- Added `system.jemalloc_stats` table and `/jemalloc.html` HTTP endpoint for interactive visualization of jemalloc memory allocator statistics. [#97077](https://github.com/ClickHouse/ClickHouse/pull/97077) ([Antonio Andelic](https://github.com/antonio2368)).
- Added `system.jemalloc_profile_text` table for reading and analyzing jemalloc heap profiles, with support for raw, symbolized, and collapsed output formats. [#97218](https://github.com/ClickHouse/ClickHouse/pull/97218) ([Antonio Andelic](https://github.com/antonio2368)).
- Added `mutation_ids` to `system.part_log` for `MUTATE_PART` and `MUTATE_PART_START` events. [#93811](https://github.com/ClickHouse/ClickHouse/pull/93811) ([Shaohua Wang](https://github.com/tiandiwonder)).
- Nested global server settings (e.g. `logger.level`) are now partially visible in `system.server_settings`. [#94001](https://github.com/ClickHouse/ClickHouse/pull/94001) ([Hechem Selmi](https://github.com/m-selmi)).
- `view_duration_ms` now shows the time a group was active, rather than the sum of thread durations. [#94966](https://github.com/ClickHouse/ClickHouse/pull/94966) ([Sema Checherinda](https://github.com/CheSema)).
- `system.blob_storage_log` is now available for Azure Blob Storage, Local, and HDFS. Added `error_code` column. [#93105](https://github.com/ClickHouse/ClickHouse/pull/93105) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- Background tasks slower than average are now logged with a configurable threshold (`background_schedule_pool_log.duration_threshold_milliseconds`, default 30ms). [#92965](https://github.com/ClickHouse/ClickHouse/pull/92965) ([Azat Khuzhin](https://github.com/azat)).
- Passwords from URL storage are no longer shown in the query log. [#93245](https://github.com/ClickHouse/ClickHouse/pull/93245) ([Konstantin Vedernikov](https://github.com/scanhex12)).

### ClickHouse Keeper[​](#clickhouse-keeper-improvements "Direct link to ClickHouse Keeper")

- Correctly handles gaps in Keeper log entries if logs are before the last committed index. [#90403](https://github.com/ClickHouse/ClickHouse/pull/90403) ([Antonio Andelic](https://github.com/antonio2368)).
- Added OpenTelemetry tracing for Keeper requests. [#91332](https://github.com/ClickHouse/ClickHouse/pull/91332) ([Miсhael Stetsyuk](https://github.com/mstetsyuk)).
- Added new Keeper metrics: `KeeperChangelogWrittenBytes`, `KeeperChangelogFileSyncMicroseconds`, `KeeperSnapshotWrittenBytes`, `KeeperSnapshotFileSyncMicroseconds`, `KeeperBatchSizeElements`, and `KeeperBatchSizeBytes`. [#92149](https://github.com/ClickHouse/ClickHouse/pull/92149) ([Miсhael Stetsyuk](https://github.com/mstetsyuk)).
- `CHECK_STAT` and `TRY_REMOVE` Keeper extensions are now enabled by default. [#93886](https://github.com/ClickHouse/ClickHouse/pull/93886) ([Mikhail Artemenko](https://github.com/Michicosun)).
- Keeper now throws an exception instead of aborting when it detects a broken snapshot or inconsistent changelogs, requiring manual intervention for safer recovery. [#94168](https://github.com/ClickHouse/ClickHouse/pull/94168) ([Antonio Andelic](https://github.com/antonio2368)).
- Added `with_data` and `with_stat` extensions to `getChildren` Keeper requests, allowing fetching children along with their data and stats in a single operation. [#94826](https://github.com/ClickHouse/ClickHouse/pull/94826) ([Nikolay Degterinsky](https://github.com/evillique)).
- Added a check for Keeper misconfiguration that could lead to cluster assembly failures. [#94682](https://github.com/ClickHouse/ClickHouse/pull/94682) ([Konstantin Bogdanov](https://github.com/thevar1able)).
- Added `with_data` Keeper extension support to improve table fetching in Database Replicated. [#96090](https://github.com/ClickHouse/ClickHouse/pull/96090) ([Nikolay Degterinsky](https://github.com/evillique)).
- Auxiliary ZooKeeper can now be inserted into via `system.zookeeper`. [#92092](https://github.com/ClickHouse/ClickHouse/pull/92092) ([RinChanNOW](https://github.com/RinChanNOWWW)).

### Memory management[​](#memory-management-improvements "Direct link to Memory management")