v25.8 Changelog for Cloud

### Iceberg and DataLake fixes[​](#iceberg-and-datalake-fixes "Direct link to Iceberg and DataLake fixes")

- Fix the metadata resolution when querying iceberg tables through rest catalog. ... [#80562](https://github.com/ClickHouse/ClickHouse/pull/80562) ([Saurabh Kumar Ojha](https://github.com/saurabhojha)).
- Fix data races in Iceberg. [#82088](https://github.com/ClickHouse/ClickHouse/pull/82088) ([Azat Khuzhin](https://github.com/azat)).
- Fix "Context has expired" for Iceberg. [#82146](https://github.com/ClickHouse/ClickHouse/pull/82146) ([Azat Khuzhin](https://github.com/azat)).
- Now ClickHouse can read iceberg tables from Glue catalog after schema evolution. Fixes [#81272](https://github.com/ClickHouse/ClickHouse/issues/81272). [#82301](https://github.com/ClickHouse/ClickHouse/pull/82301) ([alesapin](https://github.com/alesapin)).
- Fix data races in Iceberg. [#82841](https://github.com/ClickHouse/ClickHouse/pull/82841) ([Azat Khuzhin](https://github.com/azat)).
- Disable bounds-based file pruning for iceberg array element and iceberg map values, including all their nested subfields. [#83520](https://github.com/ClickHouse/ClickHouse/pull/83520) ([Daniil Ivanik](https://github.com/divanik)).
- Fix iceberg writes for complex types. [#85330](https://github.com/ClickHouse/ClickHouse/pull/85330) ([scanhex12](https://github.com/scanhex12)).
- Writing lower and upper bounds are not supported for complex types. [#85332](https://github.com/ClickHouse/ClickHouse/pull/85332) ([scanhex12](https://github.com/scanhex12)).
- Fix nullability of fields in iceberg. [#85977](https://github.com/ClickHouse/ClickHouse/pull/85977) ([scanhex12](https://github.com/scanhex12)).
- No longer create empty iceberg delete file. [#86061](https://github.com/ClickHouse/ClickHouse/pull/86061) ([scanhex12](https://github.com/scanhex12)).
- Update metadata timestamp in iceberg writes. [#85711](https://github.com/ClickHouse/ClickHouse/pull/85711) ([scanhex12](https://github.com/scanhex12)).
- Spark can't read position delete files. [#85762](https://github.com/ClickHouse/ClickHouse/pull/85762) ([scanhex12](https://github.com/scanhex12)).
- Stops taking schema from manifest files but stores relevant schemas for each snapshot independently. Infer relevant schema for each data file from its corresponding snapshot. Previous behaviour violated Iceberg specification for manifest files entries with existing status. [#84588](https://github.com/ClickHouse/ClickHouse/pull/84588) ([Daniil Ivanik](https://github.com/divanik)).
- Now Iceberg doesn't try to cache relevant snapshot version between select queries and always try to resolve snapshot honestly. Earlier attempt to cache iceberg snapshot led to problems with usage of Iceberg table with time travel. [#85038](https://github.com/ClickHouse/ClickHouse/pull/85038) ([Daniil Ivanik](https://github.com/divanik)).
- Fix the metadata resolution when querying iceberg tables through rest catalog. ... [#85531](https://github.com/ClickHouse/ClickHouse/pull/85531) ([Saurabh Kumar Ojha](https://github.com/saurabhojha)).
- Fix secrets masking in icebergS3Cluster and icebergAzureCluster table functions. [#85658](https://github.com/ClickHouse/ClickHouse/pull/85658) ([MikhailBurdukov](https://github.com/MikhailBurdukov)).

### DeltaLake fixes[​](#deltalake-fixes "Direct link to DeltaLake fixes")

- Fix column pruning with delta-kernel in storage `DeltaLake`. Closes [#84543](https://github.com/ClickHouse/ClickHouse/issues/84543). [#84745](https://github.com/ClickHouse/ClickHouse/pull/84745) ([Kseniia Sumarokova](https://github.com/kssenii)).
- Refresh credentials in delta-kernel in storage DeltaLake. [#84751](https://github.com/ClickHouse/ClickHouse/pull/84751) ([Kseniia Sumarokova](https://github.com/kssenii)).
- Fix segfault in delta-kernel implementation. [#85160](https://github.com/ClickHouse/ClickHouse/pull/85160) ([Kseniia Sumarokova](https://github.com/kssenii)).
- Fix race in `DeltaLake` engine delta-kernel implementation. [#85221](https://github.com/ClickHouse/ClickHouse/pull/85221) ([Kseniia Sumarokova](https://github.com/kssenii)).
- Fix reading partitioned data with disabled delta-kernel in `DeltaLake` engine. It was broken in 25.7 (<https://github.com/ClickHouse/ClickHouse/pull/81136>). [#85223](https://github.com/ClickHouse/ClickHouse/pull/85223) ([Kseniia Sumarokova](https://github.com/kssenii)).
- Change pre-25.5 value of `allow_experimental_delta_kernel_rs` to `false` for compatibility. [#84587](https://github.com/ClickHouse/ClickHouse/pull/84587) ([Kseniia Sumarokova](https://github.com/kssenii)).
- Fix reading count from cache for delta lake. [#85704](https://github.com/ClickHouse/ClickHouse/pull/85704) ([Kseniia Sumarokova](https://github.com/kssenii)).

### TTL and MergeTree fixes[​](#ttl-and-mergetree-fixes "Direct link to TTL and MergeTree fixes")

- Recalculate the min-max index when TTL reduces rows to ensure the correctness of algorithms relying on it, such as `minmax_count_projection`. This resolves [#77091](https://github.com/ClickHouse/ClickHouse/issues/77091). [#77166](https://github.com/ClickHouse/ClickHouse/pull/77166) ([Amos Bird](https://github.com/amosbird)).
- Fix incorrent TTL recalculation in TTL GROUP BY when updating TTL. [#81222](https://github.com/ClickHouse/ClickHouse/pull/81222) ([Evgeniy Ulasik](https://github.com/H0uston)).
- Fix "Context has expired" during merges when dict used in TTL expression. [#81690](https://github.com/ClickHouse/ClickHouse/pull/81690) ([Azat Khuzhin](https://github.com/azat)).
- Fix LOGICAL\_ERROR and following crash when using the same column in the TTL for GROUP BY and SET. [#82054](https://github.com/ClickHouse/ClickHouse/pull/82054) ([Pablo Marcos](https://github.com/pamarcos)).
- MergeTree now does nothing related to TTL if all TTL are removed from the table. [#84441](https://github.com/ClickHouse/ClickHouse/pull/84441) ([alesapin](https://github.com/alesapin)).
- Fix `ALTER MODIFY ORDER BY` not validating TTL columns in sorting keys. TTL columns are now properly rejected when used in `ORDER BY` clauses during `ALTER` operations, preventing potential table corruption. [#84536](https://github.com/ClickHouse/ClickHouse/pull/84536) ([xiaohuanlin](https://github.com/xiaohuanlin)).

### Projection fixes[​](#projection-fixes "Direct link to Projection fixes")

- Fix logical error during materialize projection when column type was changed to Nullable. [#80741](https://github.com/ClickHouse/ClickHouse/pull/80741) ([Pavel Kruglov](https://github.com/Avogar)).
- Fix incorrect usage of parent metadata in `mergeTreeProjection` table function when `enable_shared_storage_snapshot_in_query = 1`. This is for [#82634](https://github.com/ClickHouse/ClickHouse/issues/82634). [#82638](https://github.com/ClickHouse/ClickHouse/pull/82638) ([Amos Bird](https://github.com/amosbird)).
- Fix rare clickhouse crash when table has projection, `lightweight_mutation_projection_mode = 'rebuild'` and user execute lighweight delete which deletes ALL rows from any block in table. [#84158](https://github.com/ClickHouse/ClickHouse/pull/84158) ([alesapin](https://github.com/alesapin)).
- Fix backup of parts with broken projections. [#85362](https://github.com/ClickHouse/ClickHouse/pull/85362) ([Antonio Andelic](https://github.com/antonio2368)).
- Forbid using `_part_offset` column in projection in releases until it is stabilized. [#85372](https://github.com/ClickHouse/ClickHouse/pull/85372) ([Sema Checherinda](https://github.com/CheSema)).

### Parallel replicas fixes[​](#parallel-replicas-fixes "Direct link to Parallel replicas fixes")