title_wip

#### New Feature[​](#new-feature-11 "Direct link to New Feature")

- Implement Variant data type that represents a union of other data types. Type `Variant(T1, T2, ..., TN)` means that each row of this type has a value of either type `T1` or `T2` or ... or `TN` or none of them (`NULL` value). Variant type is available under a setting `allow_experimental_variant_type`. Reference: [#54864](https://github.com/ClickHouse/ClickHouse/issues/54864). [#58047](https://github.com/ClickHouse/ClickHouse/pull/58047) ([Kruglov Pavel](https://github.com/Avogar)).
- Certain settings (currently `min_compress_block_size` and `max_compress_block_size`) can now be specified at column-level where they take precedence over the corresponding table-level setting. Example: `CREATE TABLE tab (col String SETTINGS (min_compress_block_size = 81920, max_compress_block_size = 163840)) ENGINE = MergeTree ORDER BY tuple();`. [#55201](https://github.com/ClickHouse/ClickHouse/pull/55201) ([Duc Canh Le](https://github.com/canhld94)).
- Add `quantileDD` aggregate function as well as the corresponding `quantilesDD` and `medianDD`. It is based on the DDSketch <https://www.vldb.org/pvldb/vol12/p2195-masson.pdf>. ### Documentation entry for user-facing changes. [#56342](https://github.com/ClickHouse/ClickHouse/pull/56342) ([Srikanth Chekuri](https://github.com/srikanthccv)).
- Allow to configure any kind of object storage with any kind of metadata type. [#58357](https://github.com/ClickHouse/ClickHouse/pull/58357) ([Kseniia Sumarokova](https://github.com/kssenii)).
- Added `null_status_on_timeout_only_active` and `throw_only_active` modes for `distributed_ddl_output_mode` that allow to avoid waiting for inactive replicas. [#58350](https://github.com/ClickHouse/ClickHouse/pull/58350) ([Alexander Tokmakov](https://github.com/tavplubix)).
- Add function `arrayShingles` to compute subarrays, e.g. `arrayShingles([1, 2, 3, 4, 5], 3)` returns `[[1,2,3],[2,3,4],[3,4,5]]`. [#58396](https://github.com/ClickHouse/ClickHouse/pull/58396) ([Zheng Miao](https://github.com/zenmiao7)).
- Added functions `punycodeEncode`, `punycodeDecode`, `idnaEncode` and `idnaDecode` which are useful for translating international domain names to an ASCII representation according to the IDNA standard. [#58454](https://github.com/ClickHouse/ClickHouse/pull/58454) ([Robert Schulze](https://github.com/rschu1ze)).
- Added string similarity functions `dramerauLevenshteinDistance`, `jaroSimilarity` and `jaroWinklerSimilarity`. [#58531](https://github.com/ClickHouse/ClickHouse/pull/58531) ([Robert Schulze](https://github.com/rschu1ze)).
- Add two settings `output_format_compression_level` to change output compression level and `output_format_compression_zstd_window_log` to explicitly set compression window size and enable long-range mode for zstd compression if output compression method is `zstd`. Applied for `INTO OUTFILE` and when writing to table functions `file`, `url`, `hdfs`, `s3`, and `azureBlobStorage`. [#58539](https://github.com/ClickHouse/ClickHouse/pull/58539) ([Duc Canh Le](https://github.com/canhld94)).
- Automatically disable ANSI escape sequences in Pretty formats if the output is not a terminal. Add new `auto` mode to setting `output_format_pretty_color`. [#58614](https://github.com/ClickHouse/ClickHouse/pull/58614) ([Shaun Struwig](https://github.com/Blargian)).
- Added function `sqidDecode` which decodes [Sqids](https://sqids.org/). [#58544](https://github.com/ClickHouse/ClickHouse/pull/58544) ([Robert Schulze](https://github.com/rschu1ze)).
- Allow to read Bool values into String in JSON input formats. It's done under a setting `input_format_json_read_bools_as_strings` that is enabled by default. [#58561](https://github.com/ClickHouse/ClickHouse/pull/58561) ([Kruglov Pavel](https://github.com/Avogar)).
- Added function `seriesDecomposeSTL` which decomposes a time series into a season, a trend and a residual component. [#57078](https://github.com/ClickHouse/ClickHouse/pull/57078) ([Bhavna Jindal](https://github.com/bhavnajindal)).
- Introduced MySQL Binlog Client for MaterializedMySQL: One binlog connection for many databases. [#57323](https://github.com/ClickHouse/ClickHouse/pull/57323) ([Val Doroshchuk](https://github.com/valbok)).
- Intel QuickAssist Technology (QAT) provides hardware-accelerated compression and cryptograpy. ClickHouse got a new compression codec `ZSTD_QAT` which utilizes QAT for zstd compression. The codec uses [Intel's QATlib](https://github.com/intel/qatlib) and [Inte's QAT ZSTD Plugin](https://github.com/intel/QAT-ZSTD-Plugin). Right now, only compression can be accelerated in hardware (a software fallback kicks in in case QAT could not be initialized), decompression always runs in software. [#57509](https://github.com/ClickHouse/ClickHouse/pull/57509) ([jasperzhu](https://github.com/jinjunzh)).
- Implementing the new way how object storage keys are generated for s3 disks. Now the format could be defined in terms of `re2` regex syntax with `key_template` option in disc description. [#57663](https://github.com/ClickHouse/ClickHouse/pull/57663) ([Sema Checherinda](https://github.com/CheSema)).
- Table system.dropped\_tables\_parts contains parts of system.dropped\_tables tables (dropped but not yet removed tables). [#58038](https://github.com/ClickHouse/ClickHouse/pull/58038) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
- Add settings `max_materialized_views_size_for_table` to limit the number of materialized views attached to a table. [#58068](https://github.com/ClickHouse/ClickHouse/pull/58068) ([zhongyuankai](https://github.com/zhongyuankai)).
- `clickhouse-format` improvements: support INSERT queries with `VALUES`; support comments (use `--comments` to output them); support `--max_line_length` option to format only long queries in multiline. [#58246](https://github.com/ClickHouse/ClickHouse/pull/58246) ([vdimir](https://github.com/vdimir)).
- Attach all system tables in `clickhouse-local`, including `system.parts`. This closes [#58312](https://github.com/ClickHouse/ClickHouse/issues/58312). [#58359](https://github.com/ClickHouse/ClickHouse/pull/58359) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- Support for `Enum` data types in function `transform`. This closes [#58241](https://github.com/ClickHouse/ClickHouse/issues/58241). [#58360](https://github.com/ClickHouse/ClickHouse/pull/58360) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- Add table `system.database_engines`. [#58390](https://github.com/ClickHouse/ClickHouse/pull/58390) ([Bharat Nallan](https://github.com/bharatnc)). Allow registering database engines independently in the codebase. [#58365](https://github.com/ClickHouse/ClickHouse/pull/58365) ([Bharat Nallan](https://github.com/bharatnc)). Allow registering interpreters independently. [#58443](https://github.com/ClickHouse/ClickHouse/pull/58443) ([Bharat Nallan](https://github.com/bharatnc)).
- Added `FROM <Replicas>` modifier for `SYSTEM SYNC REPLICA LIGHTWEIGHT` query. With the `FROM` modifier ensures we wait for fetches and drop-ranges only for the specified source replicas, as well as any replica not in zookeeper or with an empty source\_replica. [#58393](https://github.com/ClickHouse/ClickHouse/pull/58393) ([Jayme Bird](https://github.com/jaymebrd)).
- Added setting `update_insert_deduplication_token_in_dependent_materialized_views`. This setting allows to update insert deduplication token with table identifier during insert in dependent materialized views. Closes [#59165](https://github.com/ClickHouse/ClickHouse/issues/59165). [#59238](https://github.com/ClickHouse/ClickHouse/pull/59238) ([Maksim Kita](https://github.com/kitaisreal)).
- Added statement `SYSTEM RELOAD ASYNCHRONOUS METRICS` which updates the asynchronous metrics. Mostly useful for testing and development. [#53710](https://github.com/ClickHouse/ClickHouse/pull/53710) ([Robert Schulze](https://github.com/rschu1ze)).

#### Performance Improvement[​](#performance-improvement-11 "Direct link to Performance Improvement")