v26.2 Changelog for Cloud

### Table engines and storage[​](#table-engines-and-storage-improvements "Direct link to Table engines and storage")

- `StorageEmbeddedRocksDB` now supports multiple columns as a primary key. [#33917](https://github.com/ClickHouse/ClickHouse/pull/33917) ([usurai](https://github.com/usurai)).
- Added `ALTER TABLE <table> ATTACH PART <part_name> FROM <directory_name>` syntax, allowing attachment of parts from arbitrary subdirectories of `detached/` (e.g. parts with `broken-on-start` or `unexpected` prefixes) without manual filesystem renaming. [#74816](https://github.com/ClickHouse/ClickHouse/pull/74816) ([Anton Popov](https://github.com/CurtizJ)).
- `min_free_disk_bytes_to_perform_insert` now works correctly with JBOD volumes. [#90878](https://github.com/ClickHouse/ClickHouse/pull/90878) ([Aleksandr Musorin](https://github.com/AVMusorin)).
- `max_parts_to_merge_at_once` is now respected during TTL drop-part merges. [#95315](https://github.com/ClickHouse/ClickHouse/pull/95315) ([Kseniia Sumarokova](https://github.com/kssenii)).
- Background operations (mutate, merge) can now be configured independently via a `background` profile, rather than sharing settings with regular queries via the `default` profile. [#93905](https://github.com/ClickHouse/ClickHouse/pull/93905) ([Arsen Muk](https://github.com/arsenmuk)).
- Improved subcolumn reading with correct size calculation, reducing memory usage and improving speed. [#96251](https://github.com/ClickHouse/ClickHouse/pull/96251) ([Pavel Kruglov](https://github.com/Avogar)).
- Limited the number of pipeline streams generated with `split_intersecting_parts_ranges_into_layers` to avoid excessive memory consumption. [#96478](https://github.com/ClickHouse/ClickHouse/pull/96478) ([Nikita Taranov](https://github.com/nickitat)).
- The text index is now GA. [#96794](https://github.com/ClickHouse/ClickHouse/pull/96794) ([Robert Schulze](https://github.com/rschu1ze)).
- `QBit` is now GA. [#95358](https://github.com/ClickHouse/ClickHouse/pull/95358) ([Raufs Dunamalijevs](https://github.com/rienath)).
- `QBit` can now be compared for equality. [#94078](https://github.com/ClickHouse/ClickHouse/pull/94078) ([Raufs Dunamalijevs](https://github.com/rienath)).
- When saving table schema with `enable_positional_arguments_for_projections`, expressions are now substituted instead of positional arguments, allowing server restart with the setting disabled. [#96372](https://github.com/ClickHouse/ClickHouse/pull/96372) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- In Replicated databases, the cached cluster is no longer updated for every dummy query. [#96897](https://github.com/ClickHouse/ClickHouse/pull/96897) ([Tuan Pham Anh](https://github.com/tuanpach)).
- Added `SYSTEM RESET DDL WORKER [ON CLUSTER]` query to reset the DDLWorker state, useful for refreshing replica activity when host IDs are updated. [#93780](https://github.com/ClickHouse/ClickHouse/pull/93780) ([Tuan Pham Anh](https://github.com/tuanpach)).

### Data lakes[​](#data-lakes-improvements "Direct link to Data lakes")

- Added DeltaLake deletion vector support. [#93852](https://github.com/ClickHouse/ClickHouse/pull/93852) ([Kseniia Sumarokova](https://github.com/kssenii)).
- Deletion vectors are now also supported for `deltaLakeCluster`. [#94365](https://github.com/ClickHouse/ClickHouse/pull/94365) ([Kseniia Sumarokova](https://github.com/kssenii)).
- DeltaLake is now available on macOS. [#95985](https://github.com/ClickHouse/ClickHouse/pull/95985) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- DeltaLake now takes `count()` results from metadata and shows correct table stats (total bytes/rows) in `system.tables`. [#96190](https://github.com/ClickHouse/ClickHouse/pull/96190) ([Kseniia Sumarokova](https://github.com/kssenii)).
- Skipped object storage reads when querying DeltaLake tables from `system.tables`. [#95899](https://github.com/ClickHouse/ClickHouse/pull/95899) ([Antonio Andelic](https://github.com/antonio2368)).
- Added `SYSTEM RELOAD DELTA KERNEL TRACING <level>` command for debugging delta-kernel logging. [#96763](https://github.com/ClickHouse/ClickHouse/pull/96763) ([Kseniia Sumarokova](https://github.com/kssenii)).
- Iceberg table metadata location is now deduced automatically if `metadata_location` is not specified in Glue metadata. [#91994](https://github.com/ClickHouse/ClickHouse/pull/91994) ([Andrey Zvonov](https://github.com/zvonand)).
- Iceberg manifest file entries now parse lower and upper bounds for position delete file names, improving data file selection. [#93980](https://github.com/ClickHouse/ClickHouse/pull/93980) ([Daniil Ivanik](https://github.com/divanik)).
- Enabled `PREWHERE` optimization for Iceberg tables. [#95476](https://github.com/ClickHouse/ClickHouse/pull/95476) ([Konstantin Vedernikov](https://github.com/scanhex12)).
- Thread and memory limits are now shared between data file and position delete file readers in Iceberg tables. [#94701](https://github.com/ClickHouse/ClickHouse/pull/94701) ([Yang Jiang](https://github.com/Ted-Jiang)).
- Added support for `ALTER TABLE RENAME COLUMN` for Iceberg tables. [#97455](https://github.com/ClickHouse/ClickHouse/pull/97455) ([murphy-4o](https://github.com/murphy-4o)).
- Added Google Cloud Storage support for data lakes. [#93866](https://github.com/ClickHouse/ClickHouse/pull/93866) ([Konstantin Vedernikov](https://github.com/scanhex12)).
- S3 access tokens are now dynamically refreshed during long queries with Unity Catalog. [#95069](https://github.com/ClickHouse/ClickHouse/pull/95069) ([Konstantin Vedernikov](https://github.com/scanhex12)).
- Added role-based access to Glue catalog via `aws_role_arn` and `aws_role_session_name` settings. [#90825](https://github.com/ClickHouse/ClickHouse/pull/90825) ([Antonio Andelic](https://github.com/antonio2368)).

### S3Queue[​](#s3queue-improvements "Direct link to S3Queue")

- S3Queue now tracks hive partitioning in ordered mode. [#81040](https://github.com/ClickHouse/ClickHouse/pull/81040) ([Anton Ivashkin](https://github.com/ianton-ru)).
- Refactored S3Queue ordered mode processing with buckets, reducing the number of Keeper requests and improving performance. [#92889](https://github.com/ClickHouse/ClickHouse/pull/92889) ([Kseniia Sumarokova](https://github.com/kssenii)).
- Added more generic partitioning support for S3Queue ordered mode. [#94321](https://github.com/ClickHouse/ClickHouse/pull/94321) ([Bharat Nallan](https://github.com/bharatnc)).
- Added bucketing based on partition key for S3Queue in ordered mode. [#94698](https://github.com/ClickHouse/ClickHouse/pull/94698) ([Bharat Nallan](https://github.com/bharatnc)).
- S3Queue auxiliary ZooKeeper support via the `keeper_path` setting. [#95203](https://github.com/ClickHouse/ClickHouse/pull/95203) ([Diego Nieto](https://github.com/lesandie)).
- S3(Azure)Queue ordered mode now cleans up failed nodes by tracking limits. [#94412](https://github.com/ClickHouse/ClickHouse/pull/94412) ([Kseniia Sumarokova](https://github.com/kssenii)).

### S3 and object storage[​](#s3-and-object-storage-improvements "Direct link to S3 and object storage")