2020 Changelog

- Don't split the dictionary source's table name into schema and table name itself if ODBC connection does not support schema. [#12165](https://github.com/ClickHouse/ClickHouse/pull/12165) ([Vitaly Baranov](https://github.com/vitlibar)).
- Fixed wrong logic in `ALTER DELETE` that leads to deleting of records when condition evaluates to NULL. This fixes [#9088](https://github.com/ClickHouse/ClickHouse/issues/9088). This closes [#12106](https://github.com/ClickHouse/ClickHouse/issues/12106). [#12153](https://github.com/ClickHouse/ClickHouse/pull/12153) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- Fixed transform of query to send to external DBMS (e.g. MySQL, ODBC) in presense of aliases. This fixes [#12032](https://github.com/ClickHouse/ClickHouse/issues/12032). [#12151](https://github.com/ClickHouse/ClickHouse/pull/12151) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- Fixed bad code in redundant ORDER BY optimization. The bug was introduced in [#10067](https://github.com/ClickHouse/ClickHouse/issues/10067). [#12148](https://github.com/ClickHouse/ClickHouse/pull/12148) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- Fixed potential overflow in integer division. This fixes [#12119](https://github.com/ClickHouse/ClickHouse/issues/12119). [#12140](https://github.com/ClickHouse/ClickHouse/pull/12140) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- Fixed potential infinite loop in `greatCircleDistance`, `geoDistance`. This fixes [#12117](https://github.com/ClickHouse/ClickHouse/issues/12117). [#12137](https://github.com/ClickHouse/ClickHouse/pull/12137) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- Normalize "pid" file handling. In previous versions the server may refuse to start if it was killed without proper shutdown and if there is another process that has the same pid as previously runned server. Also pid file may be removed in unsuccessful server startup even if there is another server running. This fixes [#3501](https://github.com/ClickHouse/ClickHouse/issues/3501). [#12133](https://github.com/ClickHouse/ClickHouse/pull/12133) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- Fixed bug which leads to incorrect table metadata in ZooKeepeer for ReplicatedVersionedCollapsingMergeTree tables. Fixes [#12093](https://github.com/ClickHouse/ClickHouse/issues/12093). [#12121](https://github.com/ClickHouse/ClickHouse/pull/12121) ([alesapin](https://github.com/alesapin)).
- Avoid "There is no query" exception for materialized views with joins or with subqueries attached to system logs (system.query\_log, metric\_log, etc) or to engine=Buffer underlying table. [#12120](https://github.com/ClickHouse/ClickHouse/pull/12120) ([filimonov](https://github.com/filimonov)).
- Fixed handling dependency of table with ENGINE=Dictionary on dictionary. This fixes [#10994](https://github.com/ClickHouse/ClickHouse/issues/10994). This fixes [#10397](https://github.com/ClickHouse/ClickHouse/issues/10397). [#12116](https://github.com/ClickHouse/ClickHouse/pull/12116) ([Vitaly Baranov](https://github.com/vitlibar)).
- Format `Parquet` now properly works with `LowCardinality` and `LowCardinality(Nullable)` types. Fixes [#12086](https://github.com/ClickHouse/ClickHouse/issues/12086), [#8406](https://github.com/ClickHouse/ClickHouse/issues/8406). [#12108](https://github.com/ClickHouse/ClickHouse/pull/12108) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
- Fixed performance for selects with `UNION` caused by wrong limit for the total number of threads. Fixes [#12030](https://github.com/ClickHouse/ClickHouse/issues/12030). [#12103](https://github.com/ClickHouse/ClickHouse/pull/12103) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
- Fixed segfault with `-StateResample` combinators. [#12092](https://github.com/ClickHouse/ClickHouse/pull/12092) ([Anton Popov](https://github.com/CurtizJ)).
- Fixed empty `result_rows` and `result_bytes` metrics in `system.quey_log` for selects. Fixes [#11595](https://github.com/ClickHouse/ClickHouse/issues/11595). [#12089](https://github.com/ClickHouse/ClickHouse/pull/12089) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
- Fixed unnecessary limiting the number of threads for selects from `VIEW`. Fixes [#11937](https://github.com/ClickHouse/ClickHouse/issues/11937). [#12085](https://github.com/ClickHouse/ClickHouse/pull/12085) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
- Fixed SIGSEGV in StorageKafka on DROP TABLE. [#12075](https://github.com/ClickHouse/ClickHouse/pull/12075) ([Azat Khuzhin](https://github.com/azat)).
- Fixed possible crash while using wrong type for `PREWHERE`. Fixes [#12053](https://github.com/ClickHouse/ClickHouse/issues/12053), [#12060](https://github.com/ClickHouse/ClickHouse/issues/12060). [#12060](https://github.com/ClickHouse/ClickHouse/pull/12060) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
- Fixed error `Cannot capture column` for higher-order functions with `Tuple(LowCardinality)` argument. Fixes [#9766](https://github.com/ClickHouse/ClickHouse/issues/9766). [#12055](https://github.com/ClickHouse/ClickHouse/pull/12055) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
- Fixed constraints check if constraint is a constant expression. This fixes [#11360](https://github.com/ClickHouse/ClickHouse/issues/11360). [#12042](https://github.com/ClickHouse/ClickHouse/pull/12042) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- Fixed wrong result and potential crash when invoking function `if` with arguments of type `FixedString` with different sizes. This fixes [#11362](https://github.com/ClickHouse/ClickHouse/issues/11362). [#12021](https://github.com/ClickHouse/ClickHouse/pull/12021) ([alexey-milovidov](https://github.com/alexey-milovidov)).