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### ClickHouse release 24.9, 2024-09-26. [Presentation](https://presentations.clickhouse.com/2024-release-24.9/), [Video](https://www.youtube.com/watch?v=ray6wJGCHbs)[​](#a-id249a-clickhouse-release-249-2024-09-26 "Direct link to a-id249a-clickhouse-release-249-2024-09-26")

#### Backward Incompatible Change[​](#backward-incompatible-change-3 "Direct link to Backward Incompatible Change")

- Expressions like `a[b].c` are supported for named tuples, as well as named subscripts from arbitrary expressions, e.g., `expr().name`. This is useful for processing JSON. This closes [#54965](https://github.com/ClickHouse/ClickHouse/issues/54965). In previous versions, an expression of form `expr().name` was parsed as `tupleElement(expr(), name)`, and the query analyzer was searching for a column `name` rather than for the corresponding tuple element; while in the new version, it is changed to `tupleElement(expr(), 'name')`. In most cases, the previous version was not working, but it is possible to imagine a very unusual scenario when this change could lead to incompatibility: if you stored names of tuple elements in a column or an alias, that was named differently than the tuple element's name: `SELECT 'b' AS a, CAST([tuple(123)] AS 'Array(Tuple(b UInt8))') AS t, t[1].a`. It is very unlikely that you used such queries, but we still have to mark this change as potentially backward incompatible. [#68435](https://github.com/ClickHouse/ClickHouse/pull/68435) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- When the setting `print_pretty_type_names` is enabled, it will print `Tuple` data type in a pretty form in `SHOW CREATE TABLE` statements, `formatQuery` function, and in the interactive mode in `clickhouse-client` and `clickhouse-local`. In previous versions, this setting was only applied to `DESCRIBE` queries and `toTypeName`. This closes [#65753](https://github.com/ClickHouse/ClickHouse/issues/65753). [#68492](https://github.com/ClickHouse/ClickHouse/pull/68492) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- Do not allow explicitly specifying UUID when creating a table in `Replicated` databases. Also, do not allow explicitly specifying Keeper path and replica name for \*MergeTree tables in Replicated databases. It introduces a new setting `database_replicated_allow_explicit_uuid` and changes the type of `database_replicated_allow_replicated_engine_arguments` from Bool to UInt64 [#66104](https://github.com/ClickHouse/ClickHouse/pull/66104) ([Alexander Tokmakov](https://github.com/tavplubix)).

#### New Feature[​](#new-feature-3 "Direct link to New Feature")

- Allow a user to have multiple authentication methods instead of only one. Allow authentication methods to be reset to most recently added method. If you want to run instances on 24.8 and one on 24.9 for some time, it's better to set `max_authentication_methods_per_user` = 1 for that period to avoid potential incompatibilities. [#65277](https://github.com/ClickHouse/ClickHouse/pull/65277) ([Arthur Passos](https://github.com/arthurpassos)).
- Add support for `ATTACH PARTITION ALL FROM`. [#61987](https://github.com/ClickHouse/ClickHouse/pull/61987) ([Kirill Nikiforov](https://github.com/allmazz)).
- Add the `input_format_json_empty_as_default` setting which, when enabled, treats empty fields in JSON inputs as default values. Closes [#59339](https://github.com/ClickHouse/ClickHouse/issues/59339). [#66782](https://github.com/ClickHouse/ClickHouse/pull/66782) ([Alexis Arnaud](https://github.com/a-a-f)).
- Added functions `overlay` and `overlayUTF8` which replace parts of a string by another string. Example: `SELECT overlay('Hello New York', 'Jersey', 11)` returns `Hello New Jersey`. [#66933](https://github.com/ClickHouse/ClickHouse/pull/66933) ([李扬](https://github.com/taiyang-li)).
- Add support for lightweight deletes in partition `DELETE FROM [db.]table [ON CLUSTER cluster] [IN PARTITION partition_expr] WHERE expr;`  [#67805](https://github.com/ClickHouse/ClickHouse/pull/67805) ([sunny](https://github.com/sunny19930321)).
- Implemented comparison for `Interval` data type values of different domains (such as seconds and minutes) so they are converting now to the least supertype. [#68057](https://github.com/ClickHouse/ClickHouse/pull/68057) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).
- Add `create_if_not_exists` setting to default to `IF NOT EXISTS` behavior during CREATE statements. [#68164](https://github.com/ClickHouse/ClickHouse/pull/68164) ([Peter Nguyen](https://github.com/petern48)).
- Makes it possible to read `Iceberg` tables in Azure and locally. [#68210](https://github.com/ClickHouse/ClickHouse/pull/68210) ([Daniil Ivanik](https://github.com/divanik)).
- Query cache entries can now be dropped by tag. For example, the query cache entry created by `SELECT 1 SETTINGS use_query_cache = true, query_cache_tag = 'abc'` can now be dropped by `SYSTEM DROP QUERY CACHE TAG 'abc'`. [#68477](https://github.com/ClickHouse/ClickHouse/pull/68477) ([Michał Tabaszewski](https://github.com/pinsvin00)).
- Add storage encryption for named collections. [#68615](https://github.com/ClickHouse/ClickHouse/pull/68615) ([Pablo Marcos](https://github.com/pamarcos)).
- Add virtual column `_headers` for the `URL` table engine. Closes [#65026](https://github.com/ClickHouse/ClickHouse/issues/65026). [#68867](https://github.com/ClickHouse/ClickHouse/pull/68867) ([flynn](https://github.com/ucasfl)).
- Add `system.projections` table to track available projections. [#68901](https://github.com/ClickHouse/ClickHouse/pull/68901) ([Jordi Villar](https://github.com/jrdi)).
- Add new function `arrayZipUnaligned` for spark compatibility (which is named `arrays_zip` in Spark), which allowed unaligned arrays based on original `arrayZip`. [#69030](https://github.com/ClickHouse/ClickHouse/pull/69030) ([李扬](https://github.com/taiyang-li)).
- Added `cp`/`mv` commands for the keeper client command line application which atomically copies/moves node. [#69034](https://github.com/ClickHouse/ClickHouse/pull/69034) ([Mikhail Artemenko](https://github.com/Michicosun)).
- Adds argument `scale` (default: `true`) to function `arrayAUC` which allows to skip the normalization step (issue [#69609](https://github.com/ClickHouse/ClickHouse/issues/69609)). [#69717](https://github.com/ClickHouse/ClickHouse/pull/69717) ([gabrielmcg44](https://github.com/gabrielmcg44)).

#### Experimental feature[​](#experimental-feature-2 "Direct link to Experimental feature")