2023 Changelog

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

- Dictionary source for extracting keys by traversing regular expressions tree. It can be used for User-Agent parsing. [#40878](https://github.com/ClickHouse/ClickHouse/pull/40878) ([Vage Ogannisian](https://github.com/nooblose)). [#43858](https://github.com/ClickHouse/ClickHouse/pull/43858) ([Han Fei](https://github.com/hanfei1991)).
- Added parametrized view functionality, now it's possible to specify query parameters for the View table engine. resolves [#40907](https://github.com/ClickHouse/ClickHouse/issues/40907). [#41687](https://github.com/ClickHouse/ClickHouse/pull/41687) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
- Add `quantileInterpolatedWeighted`/`quantilesInterpolatedWeighted` functions. [#38252](https://github.com/ClickHouse/ClickHouse/pull/38252) ([Bharat Nallan](https://github.com/bharatnc)).
- Array join support for the `Map` type, like the function "explode" in Spark. [#43239](https://github.com/ClickHouse/ClickHouse/pull/43239) ([李扬](https://github.com/taiyang-li)).
- Support SQL standard binary and hex string literals. [#43785](https://github.com/ClickHouse/ClickHouse/pull/43785) ([Mo Xuan](https://github.com/mo-avatar)).
- Allow formatting `DateTime` in Joda-Time style. Refer to [the Joda-Time docs](https://joda-time.sourceforge.net/apidocs/org/joda/time/format/DateTimeFormat.html). [#43818](https://github.com/ClickHouse/ClickHouse/pull/43818) ([李扬](https://github.com/taiyang-li)).
- Implemented a fractional second formatter (`%f`) for `formatDateTime`. [#44060](https://github.com/ClickHouse/ClickHouse/pull/44060) ([ltrk2](https://github.com/ltrk2)). [#44497](https://github.com/ClickHouse/ClickHouse/pull/44497) ([Alexander Gololobov](https://github.com/davenger)).
- Added `age` function to calculate the difference between two dates or dates with time values expressed as the number of full units. Closes [#41115](https://github.com/ClickHouse/ClickHouse/issues/41115). [#44421](https://github.com/ClickHouse/ClickHouse/pull/44421) ([Robert Schulze](https://github.com/rschu1ze)).
- Add `Null` source for dictionaries. Closes [#44240](https://github.com/ClickHouse/ClickHouse/issues/44240). [#44502](https://github.com/ClickHouse/ClickHouse/pull/44502) ([mayamika](https://github.com/mayamika)).
- Allow configuring the S3 storage class with the `s3_storage_class` configuration option. Such as `<s3_storage_class>STANDARD/INTELLIGENT_TIERING</s3_storage_class>` Closes [#44443](https://github.com/ClickHouse/ClickHouse/issues/44443). [#44707](https://github.com/ClickHouse/ClickHouse/pull/44707) ([chen](https://github.com/xiedeyantu)).
- Insert default values in case of missing elements in JSON object while parsing named tuple. Add setting `input_format_json_defaults_for_missing_elements_in_named_tuple` that controls this behaviour. Closes [#45142](https://github.com/ClickHouse/ClickHouse/issues/45142)#issuecomment-1380153217. [#45231](https://github.com/ClickHouse/ClickHouse/pull/45231) ([Kruglov Pavel](https://github.com/Avogar)).
- Record server startup time in ProfileEvents (`ServerStartupMilliseconds`). Resolves [#43188](https://github.com/ClickHouse/ClickHouse/issues/43188). [#45250](https://github.com/ClickHouse/ClickHouse/pull/45250) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
- Refactor and Improve streaming engines Kafka/RabbitMQ/NATS and add support for all formats, also refactor formats a bit: - Fix producing messages in row-based formats with suffixes/prefixes. Now every message is formatted completely with all delimiters and can be parsed back using input format. - Support block-based formats like Native, Parquet, ORC, etc. Every block is formatted as a separate message. The number of rows in one message depends on the block size, so you can control it via the setting `max_block_size`. - Add new engine settings `kafka_max_rows_per_message/rabbitmq_max_rows_per_message/nats_max_rows_per_message`. They control the number of rows formatted in one message in row-based formats. Default value: 1. - Fix high memory consumption in the NATS table engine. - Support arbitrary binary data in NATS producer (previously it worked only with strings contained \0 at the end) - Add missing Kafka/RabbitMQ/NATS engine settings in the documentation. - Refactor producing and consuming in Kafka/RabbitMQ/NATS, separate it from WriteBuffers/ReadBuffers semantic. - Refactor output formats: remove callbacks on each row used in Kafka/RabbitMQ/NATS (now we don't use callbacks there), allow to use IRowOutputFormat directly, clarify row end and row between delimiters, make it possible to reset output format to start formatting again - Add proper implementation in formatRow function (bonus after formats refactoring). [#42777](https://github.com/ClickHouse/ClickHouse/pull/42777) ([Kruglov Pavel](https://github.com/Avogar)).
- Support reading/writing `Nested` tables as `List` of `Struct` in `CapnProto` format. Read/write `Decimal32/64` as `Int32/64`. Closes [#43319](https://github.com/ClickHouse/ClickHouse/issues/43319). [#43379](https://github.com/ClickHouse/ClickHouse/pull/43379) ([Kruglov Pavel](https://github.com/Avogar)).
- Added a `message_format_string` column to `system.text_log`. The column contains a pattern that was used to format the message. [#44543](https://github.com/ClickHouse/ClickHouse/pull/44543) ([Alexander Tokmakov](https://github.com/tavplubix)). This allows various analytics over the ClickHouse logs.
- Try to autodetect headers with column names (and maybe types) for CSV/TSV/CustomSeparated input formats.
  Add settings input\_format\_tsv/csv/custom\_detect\_header that enable this behaviour (enabled by default). Closes [#44640](https://github.com/ClickHouse/ClickHouse/issues/44640). [#44953](https://github.com/ClickHouse/ClickHouse/pull/44953) ([Kruglov Pavel](https://github.com/Avogar)).

#### Experimental Feature[​](#experimental-feature-7 "Direct link to Experimental Feature")

- Add an experimental inverted index as a new secondary index type for efficient text search. [#38667](https://github.com/ClickHouse/ClickHouse/pull/38667) ([larryluogit](https://github.com/larryluogit)).
- Add experimental query result cache. [#43797](https://github.com/ClickHouse/ClickHouse/pull/43797) ([Robert Schulze](https://github.com/rschu1ze)).
- Added extendable and configurable scheduling subsystem for IO requests (not yet integrated with IO code itself). [#41840](https://github.com/ClickHouse/ClickHouse/pull/41840) ([Sergei Trifonov](https://github.com/serxa)). This feature does nothing at all, enjoy.
- Added `SYSTEM DROP DATABASE REPLICA` that removes metadata of a dead replica of a `Replicated` database. Resolves [#41794](https://github.com/ClickHouse/ClickHouse/issues/41794). [#42807](https://github.com/ClickHouse/ClickHouse/pull/42807) ([Alexander Tokmakov](https://github.com/tavplubix)).

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