title_wip

- Use `MergeTree` as a default table engine. [#60524](https://github.com/ClickHouse/ClickHouse/pull/60524) ([Alexey Milovidov](https://github.com/alexey-milovidov))
- Enable `output_format_pretty_row_numbers` by default. It is better for usability. [#61791](https://github.com/ClickHouse/ClickHouse/pull/61791) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- In the previous version, some numbers in Pretty formats were not pretty enough. [#61794](https://github.com/ClickHouse/ClickHouse/pull/61794) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- A long value in Pretty formats won't be cut if it is the single value in the resultset, such as in the result of the `SHOW CREATE TABLE` query. [#61795](https://github.com/ClickHouse/ClickHouse/pull/61795) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- Similarly to `clickhouse-local`, `clickhouse-client` will accept the `--output-format` option as a synonym to the `--format` option. This closes [#59848](https://github.com/ClickHouse/ClickHouse/issues/59848). [#61797](https://github.com/ClickHouse/ClickHouse/pull/61797) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- If stdout is a terminal and the output format is not specified, `clickhouse-client` and similar tools will use `PrettyCompact` by default, similarly to the interactive mode. `clickhouse-client` and `clickhouse-local` will handle command line arguments for input and output formats in a unified fashion. This closes [#61272](https://github.com/ClickHouse/ClickHouse/issues/61272). [#61800](https://github.com/ClickHouse/ClickHouse/pull/61800) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- Underscore digit groups in Pretty formats for better readability. This is controlled by a new setting, `output_format_pretty_highlight_digit_groups`. [#61802](https://github.com/ClickHouse/ClickHouse/pull/61802) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- Add ability to override initial INSERT settings via `SYSTEM FLUSH DISTRIBUTED`. [#61832](https://github.com/ClickHouse/ClickHouse/pull/61832) ([Azat Khuzhin](https://github.com/azat)).
- Enable processors profiling (time spent/in and out bytes for sorting, aggregation, ...) by default. [#61096](https://github.com/ClickHouse/ClickHouse/pull/61096) ([Azat Khuzhin](https://github.com/azat)).
- Support files without format extension in Filesystem database. [#60795](https://github.com/ClickHouse/ClickHouse/pull/60795) ([Kruglov Pavel](https://github.com/Avogar)).
- Make all format names case insensitive, like Tsv, or TSV, or tsv, or even rowbinary. [#60420](https://github.com/ClickHouse/ClickHouse/pull/60420) ([豪肥肥](https://github.com/HowePa)). I appreciate if you will continue to write it correctly, e.g., `JSON` 😇, not `Json` 🤮, but we don't mind if you spell it as you prefer.
- Added `none_only_active` mode for `distributed_ddl_output_mode` setting. [#60340](https://github.com/ClickHouse/ClickHouse/pull/60340) ([Alexander Tokmakov](https://github.com/tavplubix)).
- The advanced dashboard has slightly better colors for multi-line graphs. [#60391](https://github.com/ClickHouse/ClickHouse/pull/60391) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- The Advanced dashboard now has controls always visible on scrolling. This allows you to add a new chart without scrolling up. [#60692](https://github.com/ClickHouse/ClickHouse/pull/60692) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- While running the `MODIFY COLUMN` query for materialized views, check the inner table's structure to ensure every column exists. [#47427](https://github.com/ClickHouse/ClickHouse/pull/47427) ([sunny](https://github.com/sunny19930321)).
- String types and Enums can be used in the same context, such as: arrays, UNION queries, conditional expressions. This closes [#60726](https://github.com/ClickHouse/ClickHouse/issues/60726). [#60727](https://github.com/ClickHouse/ClickHouse/pull/60727) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- Allow declaring Enums in the structure of external data for query processing (this is an immediate temporary table that you can provide for your query). [#57857](https://github.com/ClickHouse/ClickHouse/pull/57857) ([Duc Canh Le](https://github.com/canhld94)).
- Consider lightweight deleted rows when selecting parts to merge, so the disk size of the resulting part will be estimated better. [#58223](https://github.com/ClickHouse/ClickHouse/pull/58223) ([Zhuo Qiu](https://github.com/jewelzqiu)).
- Added comments for columns for more system tables. Continuation of <https://github.com/ClickHouse/ClickHouse/pull/58356>. [#59016](https://github.com/ClickHouse/ClickHouse/pull/59016) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
- Now we can use virtual columns in PREWHERE. It's worthwhile for non-const virtual columns like `_part_offset`. [#59033](https://github.com/ClickHouse/ClickHouse/pull/59033) ([Amos Bird](https://github.com/amosbird)). Improved overall usability of virtual columns. Now it is allowed to use virtual columns in `PREWHERE` (it's worthwhile for non-const virtual columns like `_part_offset`). Now a builtin documentation is available for virtual columns as a comment of column in `DESCRIBE` query with enabled setting `describe_include_virtual_columns`. [#60205](https://github.com/ClickHouse/ClickHouse/pull/60205) ([Anton Popov](https://github.com/CurtizJ)).
- Instead of using a constant key, now object storage generates key for determining remove objects capability. [#59495](https://github.com/ClickHouse/ClickHouse/pull/59495) ([Sema Checherinda](https://github.com/CheSema)).
- Allow "local" as object storage type instead of "local\_blob\_storage". [#60165](https://github.com/ClickHouse/ClickHouse/pull/60165) ([Kseniia Sumarokova](https://github.com/kssenii)).
- Parallel flush of pending INSERT blocks of Distributed engine on `DETACH`/server shutdown and `SYSTEM FLUSH DISTRIBUTED` (Parallelism will work only if you have multi-disk policy for a table (like everything in the Distributed engine right now)). [#60225](https://github.com/ClickHouse/ClickHouse/pull/60225) ([Azat Khuzhin](https://github.com/azat)).
- Add a setting to force read-through cache for merges. [#60308](https://github.com/ClickHouse/ClickHouse/pull/60308) ([Kseniia Sumarokova](https://github.com/kssenii)).
- An improvement for the MySQL compatibility protocol. The issue [#57598](https://github.com/ClickHouse/ClickHouse/issues/57598) mentions a variant behaviour regarding transaction handling. An issued COMMIT/ROLLBACK when no transaction is active is reported as an error contrary to MySQL behaviour. [#60338](https://github.com/ClickHouse/ClickHouse/pull/60338) ([PapaToemmsn](https://github.com/PapaToemmsn)).
- Function `substring` now has a new alias `byteSlice`. [#60494](https://github.com/ClickHouse/ClickHouse/pull/60494) ([Robert Schulze](https://github.com/rschu1ze)).
- Renamed server setting `dns_cache_max_size` to `dns_cache_max_entries` to reduce ambiguity. [#60500](https://github.com/ClickHouse/ClickHouse/pull/60500) ([Kirill Nikiforov](https://github.com/allmazz)).
- `SHOW INDEX | INDEXES | INDICES | KEYS` no longer sorts by the primary key columns (which was unintuitive). [#60514](https://github.com/ClickHouse/ClickHouse/pull/60514) ([Robert Schulze](https://github.com/rschu1ze)).
- Keeper improvement: abort during startup if an invalid snapshot is detected to avoid data loss. [#60537](https://github.com/ClickHouse/ClickHouse/pull/60537) ([Antonio Andelic](https://github.com/antonio2368)).
- Update tzdata to 2024a. [#60768](https://github.com/ClickHouse/ClickHouse/pull/60768) ([Raúl Marín](https://github.com/Algunenano)).
- Keeper improvement: support `leadership_expiry_ms` in Keeper's settings. [#60806](https://github.com/ClickHouse/ClickHouse/pull/60806) ([Brokenice0415](https://github.com/Brokenice0415)).