2023 Changelog

- Add a new `MergeTree` setting `add_implicit_sign_column_constraint_for_collapsing_engine` (disabled by default). When enabled, it adds an implicit CHECK constraint for `CollapsingMergeTree` tables that restricts the value of the `Sign` column to be only -1 or 1. [#56701](https://github.com/ClickHouse/ClickHouse/issues/56701). [#56986](https://github.com/ClickHouse/ClickHouse/pull/56986) ([Kevin Mingtarja](https://github.com/kevinmingtarja)).
- Enable adding new disk to storage configuration without restart. [#56367](https://github.com/ClickHouse/ClickHouse/pull/56367) ([Duc Canh Le](https://github.com/canhld94)).
- Support creating and materializing index in the same alter query, also support "modify TTL" and "materialize TTL" in the same query. Closes [#55651](https://github.com/ClickHouse/ClickHouse/issues/55651). [#56331](https://github.com/ClickHouse/ClickHouse/pull/56331) ([flynn](https://github.com/ucasfl)).
- Add a new table function named `fuzzJSON` with rows containing perturbed versions of the source JSON string with random variations. [#56490](https://github.com/ClickHouse/ClickHouse/pull/56490) ([Julia Kartseva](https://github.com/jkartseva)).
- Engine `Merge` filters the records according to the row policies of the underlying tables, so you don't have to create another row policy on a `Merge` table. [#50209](https://github.com/ClickHouse/ClickHouse/pull/50209) ([Ilya Golshtein](https://github.com/ilejn)).
- Add a setting `max_execution_time_leaf` to limit the execution time on shard for distributed query, and `timeout_overflow_mode_leaf` to control the behaviour if timeout happens. [#51823](https://github.com/ClickHouse/ClickHouse/pull/51823) ([Duc Canh Le](https://github.com/canhld94)).
- Add ClickHouse setting to disable tunneling for HTTPS requests over HTTP proxy. [#55033](https://github.com/ClickHouse/ClickHouse/pull/55033) ([Arthur Passos](https://github.com/arthurpassos)).
- Set `background_fetches_pool_size` to 16, background\_schedule\_pool\_size to 512 that is better for production usage with frequent small insertions. [#54327](https://github.com/ClickHouse/ClickHouse/pull/54327) ([Denny Crane](https://github.com/den-crane)).
- While read data from a csv format file, and at end of line is `\r` , which not followed by `\n`, then we will enconter the exception as follows `Cannot parse CSV format: found \r (CR) not followed by \n (LF). Line must end by \n (LF) or \r\n (CR LF) or \n\r.` In clickhouse, the csv end of line must be `\n` or `\r\n` or `\n\r`, so the `\r` must be followed by `\n`, but in some situation, the csv input data is abnormal, like above, `\r` is at end of line. [#54340](https://github.com/ClickHouse/ClickHouse/pull/54340) ([KevinyhZou](https://github.com/KevinyhZou)).
- Update Arrow library to release-13.0.0 that supports new encodings. Closes [#44505](https://github.com/ClickHouse/ClickHouse/issues/44505). [#54800](https://github.com/ClickHouse/ClickHouse/pull/54800) ([Kruglov Pavel](https://github.com/Avogar)).
- Improve performance of ON CLUSTER queries by removing heavy system calls to get all network interfaces when looking for local ip address in the DDL entry hosts list. [#54909](https://github.com/ClickHouse/ClickHouse/pull/54909) ([Duc Canh Le](https://github.com/canhld94)).
- Fixed accounting of memory allocated before attaching a thread to a query or a user. [#56089](https://github.com/ClickHouse/ClickHouse/pull/56089) ([Nikita Taranov](https://github.com/nickitat)).
- Add support for `LARGE_LIST` in Apache Arrow formats. [#56118](https://github.com/ClickHouse/ClickHouse/pull/56118) ([edef](https://github.com/edef1c)).
- Allow manual compaction of `EmbeddedRocksDB` via `OPTIMIZE` query. [#56225](https://github.com/ClickHouse/ClickHouse/pull/56225) ([Azat Khuzhin](https://github.com/azat)).
- Add ability to specify BlockBasedTableOptions for `EmbeddedRocksDB` tables. [#56264](https://github.com/ClickHouse/ClickHouse/pull/56264) ([Azat Khuzhin](https://github.com/azat)).
- `SHOW COLUMNS` now displays MySQL's equivalent data type name when the connection was made through the MySQL protocol. Previously, this was the case when setting `use_mysql_types_in_show_columns = 1`. The setting is retained but made obsolete. [#56277](https://github.com/ClickHouse/ClickHouse/pull/56277) ([Robert Schulze](https://github.com/rschu1ze)).
- Fixed possible `The local set of parts of table doesn't look like the set of parts in ZooKeeper` error if server was restarted just after `TRUNCATE` or `DROP PARTITION`. [#56282](https://github.com/ClickHouse/ClickHouse/pull/56282) ([Alexander Tokmakov](https://github.com/tavplubix)).
- Fixed handling of non-const query strings in functions `formatQuery`/ `formatQuerySingleLine`. Also added `OrNull` variants of both functions that return a NULL when a query cannot be parsed instead of throwing an exception. [#56327](https://github.com/ClickHouse/ClickHouse/pull/56327) ([Robert Schulze](https://github.com/rschu1ze)).
- Allow backup of materialized view with dropped inner table instead of failing the backup. [#56387](https://github.com/ClickHouse/ClickHouse/pull/56387) ([Kseniia Sumarokova](https://github.com/kssenii)).
- Queries to `system.replicas` initiate requests to ZooKeeper when certain columns are queried. When there are thousands of tables these requests might produce a considerable load on ZooKeeper. If there are multiple simultaneous queries to `system.replicas` they do same requests multiple times. The change is to "deduplicate" requests from concurrent queries. [#56420](https://github.com/ClickHouse/ClickHouse/pull/56420) ([Alexander Gololobov](https://github.com/davenger)).
- Fix translation to MySQL compatible query for querying external databases. [#56456](https://github.com/ClickHouse/ClickHouse/pull/56456) ([flynn](https://github.com/ucasfl)).
- Add support for backing up and restoring tables using `KeeperMap` engine. [#56460](https://github.com/ClickHouse/ClickHouse/pull/56460) ([Antonio Andelic](https://github.com/antonio2368)).
- 404 response for CompleteMultipartUpload has to be rechecked. Operation could be done on server even if client got timeout or other network errors. The next retry of CompleteMultipartUpload receives 404 response. If the object key exists that operation is considered as successful. [#56475](https://github.com/ClickHouse/ClickHouse/pull/56475) ([Sema Checherinda](https://github.com/CheSema)).
- Enable the HTTP OPTIONS method by default - it simplifies requesting ClickHouse from a web browser. [#56483](https://github.com/ClickHouse/ClickHouse/pull/56483) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- The value for `dns_max_consecutive_failures` was changed by mistake in [#46550](https://github.com/ClickHouse/ClickHouse/issues/46550) - this is reverted and adjusted to a better value. Also, increased the HTTP keep-alive timeout to a reasonable value from production. [#56485](https://github.com/ClickHouse/ClickHouse/pull/56485) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- Load base backups lazily (a base backup won't be loaded until it's needed). Also add some log message and profile events for backups. [#56516](https://github.com/ClickHouse/ClickHouse/pull/56516) ([Vitaly Baranov](https://github.com/vitlibar)).
- Setting `query_cache_store_results_of_queries_with_nondeterministic_functions` (with values `false` or `true`) was marked obsolete. It was replaced by setting `query_cache_nondeterministic_function_handling`, a three-valued enum that controls how the query cache handles queries with non-deterministic functions: a) throw an exception (default behavior), b) save the non-deterministic query result regardless, or c) ignore, i.e. don't throw an exception and don't cache the result. [#56519](https://github.com/ClickHouse/ClickHouse/pull/56519) ([Robert Schulze](https://github.com/rschu1ze)).
- Rewrite equality with `is null` check in JOIN ON section. Experimental *Analyzer only*. [#56538](https://github.com/ClickHouse/ClickHouse/pull/56538) ([vdimir](https://github.com/vdimir)).