2023 Changelog

- 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)).
- Function`concat` now supports arbitrary argument types (instead of only String and FixedString arguments). This makes it behave more similar to MySQL `concat` implementation. For example, `SELECT concat('ab', 42)` now returns `ab42`. [#56540](https://github.com/ClickHouse/ClickHouse/pull/56540) ([Serge Klochkov](https://github.com/slvrtrn)).
- Allow getting cache configuration from 'named\_collection' section in config or from SQL created named collections. [#56541](https://github.com/ClickHouse/ClickHouse/pull/56541) ([Kseniia Sumarokova](https://github.com/kssenii)).
- PostgreSQL database engine: Make the removal of outdated tables less aggressive with unsuccessful postgres connection. [#56609](https://github.com/ClickHouse/ClickHouse/pull/56609) ([jsc0218](https://github.com/jsc0218)).
- It took too much time to connnect to PG when URL is not right, so the relevant query stucks there and get cancelled. [#56648](https://github.com/ClickHouse/ClickHouse/pull/56648) ([jsc0218](https://github.com/jsc0218)).
- Keeper improvement: disable compressed logs by default in Keeper. [#56763](https://github.com/ClickHouse/ClickHouse/pull/56763) ([Antonio Andelic](https://github.com/antonio2368)).
- Add config setting `wait_dictionaries_load_at_startup`. [#56782](https://github.com/ClickHouse/ClickHouse/pull/56782) ([Vitaly Baranov](https://github.com/vitlibar)).
- There was a potential vulnerability in previous ClickHouse versions: if a user has connected and unsuccessfully tried to authenticate with the "interserver secret" method, the server didn't terminate the connection immediately but continued to receive and ignore the leftover packets from the client. While these packets are ignored, they are still parsed, and if they use a compression method with another known vulnerability, it will lead to exploitation of it without authentication. This issue was found with [ClickHouse Bug Bounty Program](https://github.com/ClickHouse/ClickHouse/issues/38986) by <https://twitter.com/malacupa>. [#56794](https://github.com/ClickHouse/ClickHouse/pull/56794) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- Fetching a part waits when that part is fully committed on remote replica. It is better not send part in PreActive state. In case of zero copy this is mandatory restriction. [#56808](https://github.com/ClickHouse/ClickHouse/pull/56808) ([Sema Checherinda](https://github.com/CheSema)).
- Fix possible postgresql logical replication conversion error when using experimental `MaterializedPostgreSQL`. [#53721](https://github.com/ClickHouse/ClickHouse/pull/53721) ([takakawa](https://github.com/takakawa)).
- Implement user-level setting `alter_move_to_space_execute_async` which allow to execute queries `ALTER TABLE ... MOVE PARTITION|PART TO DISK|VOLUME` asynchronously. The size of pool for background executions is controlled by `background_move_pool_size`. Default behavior is synchronous execution. Fixes [#47643](https://github.com/ClickHouse/ClickHouse/issues/47643). [#56809](https://github.com/ClickHouse/ClickHouse/pull/56809) ([alesapin](https://github.com/alesapin)).
- Able to filter by engine when scanning system.tables, avoid unnecessary (potentially time-consuming) connection. [#56813](https://github.com/ClickHouse/ClickHouse/pull/56813) ([jsc0218](https://github.com/jsc0218)).
- Show `total_bytes` and `total_rows` in system tables for RocksDB storage. [#56816](https://github.com/ClickHouse/ClickHouse/pull/56816) ([Aleksandr Musorin](https://github.com/AVMusorin)).
- Allow basic commands in ALTER for TEMPORARY tables. [#56892](https://github.com/ClickHouse/ClickHouse/pull/56892) ([Sergey](https://github.com/icuken)).
- LZ4 compression. Buffer compressed block in a rare case when out buffer capacity is not enough for writing compressed block directly to out's buffer. [#56938](https://github.com/ClickHouse/ClickHouse/pull/56938) ([Sema Checherinda](https://github.com/CheSema)).
- Add metrics for the number of queued jobs, which is useful for the IO thread pool. [#56958](https://github.com/ClickHouse/ClickHouse/pull/56958) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- Add a setting for PostgreSQL table engine setting in the config file. Added a check for the setting Added documentation around the additional setting. [#56959](https://github.com/ClickHouse/ClickHouse/pull/56959) ([Peignon Melvyn](https://github.com/melvynator)).
- Function `concat` can now be called with a single argument, e.g., `SELECT concat('abc')`. This makes its behavior more consistent with MySQL's concat implementation. [#57000](https://github.com/ClickHouse/ClickHouse/pull/57000) ([Serge Klochkov](https://github.com/slvrtrn)).
- Signs all `x-amz-*` headers as required by AWS S3 docs. [#57001](https://github.com/ClickHouse/ClickHouse/pull/57001) ([Arthur Passos](https://github.com/arthurpassos)).
- Function `fromDaysSinceYearZero` (alias: `FROM_DAYS`) can now be used with unsigned and signed integer types (previously, it had to be an unsigned integer). This improve compatibility with 3rd party tools such as Tableau Online. [#57002](https://github.com/ClickHouse/ClickHouse/pull/57002) ([Serge Klochkov](https://github.com/slvrtrn)).
- Add `system.s3queue_log` to default config. [#57036](https://github.com/ClickHouse/ClickHouse/pull/57036) ([Kseniia Sumarokova](https://github.com/kssenii)).
- Change the default for `wait_dictionaries_load_at_startup` to true, and use this setting only if `dictionaries_lazy_load` is false. [#57133](https://github.com/ClickHouse/ClickHouse/pull/57133) ([Vitaly Baranov](https://github.com/vitlibar)).
- Check dictionary source type on creation even if `dictionaries_lazy_load` is enabled. [#57134](https://github.com/ClickHouse/ClickHouse/pull/57134) ([Vitaly Baranov](https://github.com/vitlibar)).
- Plan-level optimizations can now be enabled/disabled individually. Previously, it was only possible to disable them all. The setting which previously did that (`query_plan_enable_optimizations`) is retained and can still be used to disable all optimizations. [#57152](https://github.com/ClickHouse/ClickHouse/pull/57152) ([Robert Schulze](https://github.com/rschu1ze)).
- The server's exit code will correspond to the exception code. For example, if the server cannot start due to memory limit, it will exit with the code 241 = MEMORY\_LIMIT\_EXCEEDED. In previous versions, the exit code for exceptions was always 70 = Poco::Util::ExitCode::EXIT\_SOFTWARE. [#57153](https://github.com/ClickHouse/ClickHouse/pull/57153) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- Do not demangle and symbolize stack frames from `functional` C++ header. [#57201](https://github.com/ClickHouse/ClickHouse/pull/57201) ([Mike Kot](https://github.com/myrrc)).
- HTTP server page `/dashboard` now supports charts with multiple lines. [#57236](https://github.com/ClickHouse/ClickHouse/pull/57236) ([Sergei Trifonov](https://github.com/serxa)).
- The `max_memory_usage_in_client` command line option supports a string value with a suffix (K, M, G, etc). Closes [#56879](https://github.com/ClickHouse/ClickHouse/issues/56879). [#57273](https://github.com/ClickHouse/ClickHouse/pull/57273) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).