2023 Changelog

- Added array operations for multiplying, dividing and modulo on scalar. Works in each way, for example `5 * [5, 5]` and `[5, 5] * 5` - both cases are possible. [#54608](https://github.com/ClickHouse/ClickHouse/pull/54608) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).
- Add optional `version` argument to `rm` command in `keeper-client` to support safer deletes. [#54708](https://github.com/ClickHouse/ClickHouse/pull/54708) ([János Benjamin Antal](https://github.com/antaljanosbenjamin)).
- Disable killing the server by systemd (that may lead to data loss when using Buffer tables). [#54744](https://github.com/ClickHouse/ClickHouse/pull/54744) ([Azat Khuzhin](https://github.com/azat)).
- Added field `is_deterministic` to system table `system.functions` which indicates whether the result of a function is stable between two invocations (given exactly the same inputs) or not. [#54766](https://github.com/ClickHouse/ClickHouse/pull/54766) [#55035](https://github.com/ClickHouse/ClickHouse/pull/55035) ([Robert Schulze](https://github.com/rschu1ze)).
- Made the views in schema `information_schema` more compatible with the equivalent views in MySQL (i.e. modified and extended them) up to a point where Tableau Online is able to connect to ClickHouse. More specifically: 1. The type of field `information_schema.tables.table_type` changed from Enum8 to String. 2. Added fields `table_comment` and `table_collation` to view `information_schema.table`. 3. Added views `information_schema.key_column_usage` and `referential_constraints`. 4. Replaced uppercase aliases in `information_schema` views with concrete uppercase columns. [#54773](https://github.com/ClickHouse/ClickHouse/pull/54773) ([Serge Klochkov](https://github.com/slvrtrn)).
- The query cache now returns an error if you try to cache the result of a query with a non-deterministic function such as `now`, `randomString` and `dictGet`. Compared to the previous behavior (silently don't cache the result), this reduces confusion and surprise. [#54801](https://github.com/ClickHouse/ClickHouse/pull/54801) ([Robert Schulze](https://github.com/rschu1ze)).
- Forbid special columns like materialized/ephemeral/alias for `file`/`s3`/`url`/... storages, fix insert into ephemeral columns from files. Closes [#53477](https://github.com/ClickHouse/ClickHouse/issues/53477). [#54803](https://github.com/ClickHouse/ClickHouse/pull/54803) ([Kruglov Pavel](https://github.com/Avogar)).
- More configurable collecting metadata for backup. [#54804](https://github.com/ClickHouse/ClickHouse/pull/54804) ([Vitaly Baranov](https://github.com/vitlibar)).
- `clickhouse-local`'s log file (if enabled with --server\_logs\_file flag) will now prefix each line with timestamp, thread id, etc, just like `clickhouse-server`. [#54807](https://github.com/ClickHouse/ClickHouse/pull/54807) ([Michael Kolupaev](https://github.com/al13n321)).
- Field `is_obsolete` in the `system.merge_tree_settings` table - it is now 1 for obsolete merge tree settings. Previously, only the description indicated that the setting is obsolete. [#54837](https://github.com/ClickHouse/ClickHouse/pull/54837) ([Robert Schulze](https://github.com/rschu1ze)).
- Make it possible to use plural when using interval literals. `INTERVAL 2 HOURS` should be equivalent to `INTERVAL 2 HOUR`. [#54860](https://github.com/ClickHouse/ClickHouse/pull/54860) ([Jordi Villar](https://github.com/jrdi)).
- Always allow the creation of a projection with `Nullable` PK. This fixes [#54814](https://github.com/ClickHouse/ClickHouse/issues/54814). [#54895](https://github.com/ClickHouse/ClickHouse/pull/54895) ([Amos Bird](https://github.com/amosbird)).
- Retry backup's S3 operations after connection reset failure. [#54900](https://github.com/ClickHouse/ClickHouse/pull/54900) ([Vitaly Baranov](https://github.com/vitlibar)).
- Make the exception message exact in case of the maximum value of a settings is less than the minimum value. [#54925](https://github.com/ClickHouse/ClickHouse/pull/54925) ([János Benjamin Antal](https://github.com/antaljanosbenjamin)).
- `LIKE`, `match`, and other regular expressions matching functions now allow matching with patterns containing non-UTF-8 substrings by falling back to binary matching. Example: you can use `string LIKE '\xFE\xFF%'` to detect BOM. This closes [#54486](https://github.com/ClickHouse/ClickHouse/issues/54486). [#54942](https://github.com/ClickHouse/ClickHouse/pull/54942) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- Added `ContextLockWaitMicroseconds` profile event. [#55029](https://github.com/ClickHouse/ClickHouse/pull/55029) ([Maksim Kita](https://github.com/kitaisreal)).
- The Keeper dynamically adjusts log levels. [#50372](https://github.com/ClickHouse/ClickHouse/pull/50372) ([helifu](https://github.com/helifu)).
- Added function `timestamp` for compatibility with MySQL. Closes [#54275](https://github.com/ClickHouse/ClickHouse/issues/54275). [#54639](https://github.com/ClickHouse/ClickHouse/pull/54639) ([Nikolay Degterinsky](https://github.com/evillique)).