2019 Changelog

- Fix bug with incorrect skip indices serialization and aggregation with adaptive granularity. [#6594](https://github.com/ClickHouse/ClickHouse/issues/6594). [#6748](https://github.com/ClickHouse/ClickHouse/pull/6748) ([alesapin](https://github.com/alesapin))
- Fix `WITH ROLLUP` and `WITH CUBE` modifiers of `GROUP BY` with two-level aggregation. [#6225](https://github.com/ClickHouse/ClickHouse/pull/6225) ([Anton Popov](https://github.com/CurtizJ))
- Fix bug with writing secondary indices marks with adaptive granularity. [#6126](https://github.com/ClickHouse/ClickHouse/pull/6126) ([alesapin](https://github.com/alesapin))
- Fix initialization order while server startup. Since `StorageMergeTree::background_task_handle` is initialized in `startup()` the `MergeTreeBlockOutputStream::write()` may try to use it before initialization. Just check if it is initialized. [#6080](https://github.com/ClickHouse/ClickHouse/pull/6080) ([Ivan](https://github.com/abyss7))
- Clearing the data buffer from the previous read operation that was completed with an error. [#6026](https://github.com/ClickHouse/ClickHouse/pull/6026) ([Nikolay](https://github.com/bopohaa))
- Fix bug with enabling adaptive granularity when creating a new replica for Replicated\*MergeTree table. [#6394](https://github.com/ClickHouse/ClickHouse/issues/6394) [#6452](https://github.com/ClickHouse/ClickHouse/pull/6452) ([alesapin](https://github.com/alesapin))
- Fixed possible crash during server startup in case of exception happened in `libunwind` during exception at access to uninitialized `ThreadStatus` structure. [#6456](https://github.com/ClickHouse/ClickHouse/pull/6456) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov))
- Fix crash in `yandexConsistentHash` function. Found by fuzz test. [#6304](https://github.com/ClickHouse/ClickHouse/issues/6304) [#6305](https://github.com/ClickHouse/ClickHouse/pull/6305) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Fixed the possibility of hanging queries when server is overloaded and global thread pool becomes near full. This have higher chance to happen on clusters with large number of shards (hundreds), because distributed queries allocate a thread per connection to each shard. For example, this issue may reproduce if a cluster of 330 shards is processing 30 concurrent distributed queries. This issue affects all versions starting from 19.2. [#6301](https://github.com/ClickHouse/ClickHouse/pull/6301) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Fixed logic of `arrayEnumerateUniqRanked` function. [#6423](https://github.com/ClickHouse/ClickHouse/pull/6423) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Fix segfault when decoding symbol table. [#6603](https://github.com/ClickHouse/ClickHouse/pull/6603) ([Amos Bird](https://github.com/amosbird))
- Fixed irrelevant exception in cast of `LowCardinality(Nullable)` to not-Nullable column in case if it does not contain Nulls (e.g. in query like `SELECT CAST(CAST('Hello' AS LowCardinality(Nullable(String))) AS String)`. [#6094](https://github.com/ClickHouse/ClickHouse/issues/6094) [#6119](https://github.com/ClickHouse/ClickHouse/pull/6119) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
- Removed extra quoting of description in `system.settings` table. [#6696](https://github.com/ClickHouse/ClickHouse/issues/6696) [#6699](https://github.com/ClickHouse/ClickHouse/pull/6699) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Avoid possible deadlock in `TRUNCATE` of Replicated table. [#6695](https://github.com/ClickHouse/ClickHouse/pull/6695) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Fix reading in order of sorting key. [#6189](https://github.com/ClickHouse/ClickHouse/pull/6189) ([Anton Popov](https://github.com/CurtizJ))
- Fix `ALTER TABLE ... UPDATE` query for tables with `enable_mixed_granularity_parts=1`. [#6543](https://github.com/ClickHouse/ClickHouse/pull/6543) ([alesapin](https://github.com/alesapin))
- Fix bug opened by [#4405](https://github.com/ClickHouse/ClickHouse/pull/4405) (since 19.4.0). Reproduces in queries to Distributed tables over MergeTree tables when we does not query any columns (`SELECT 1`). [#6236](https://github.com/ClickHouse/ClickHouse/pull/6236) ([alesapin](https://github.com/alesapin))
- Fixed overflow in integer division of signed type to unsigned type. The behaviour was exactly as in C or C++ language (integer promotion rules) that may be surprising. Please note that the overflow is still possible when dividing large signed number to large unsigned number or vice-versa (but that case is less usual). The issue existed in all server versions. [#6214](https://github.com/ClickHouse/ClickHouse/issues/6214) [#6233](https://github.com/ClickHouse/ClickHouse/pull/6233) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Limit maximum sleep time for throttling when `max_execution_speed` or `max_execution_speed_bytes` is set. Fixed false errors like `Estimated query execution time (inf seconds) is too long`. [#5547](https://github.com/ClickHouse/ClickHouse/issues/5547) [#6232](https://github.com/ClickHouse/ClickHouse/pull/6232) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Fixed issues about using `MATERIALIZED` columns and aliases in `MaterializedView`. [#448](https://github.com/ClickHouse/ClickHouse/issues/448) [#3484](https://github.com/ClickHouse/ClickHouse/issues/3484) [#3450](https://github.com/ClickHouse/ClickHouse/issues/3450) [#2878](https://github.com/ClickHouse/ClickHouse/issues/2878) [#2285](https://github.com/ClickHouse/ClickHouse/issues/2285) [#3796](https://github.com/ClickHouse/ClickHouse/pull/3796) ([Amos Bird](https://github.com/amosbird)) [#6316](https://github.com/ClickHouse/ClickHouse/pull/6316) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Fix `FormatFactory` behaviour for input streams which are not implemented as processor. [#6495](https://github.com/ClickHouse/ClickHouse/pull/6495) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
- Fixed typo. [#6631](https://github.com/ClickHouse/ClickHouse/pull/6631) ([Alex Ryndin](https://github.com/alexryndin))
- Typo in the error message ( is -> are ). [#6839](https://github.com/ClickHouse/ClickHouse/pull/6839) ([Denis Zhuravlev](https://github.com/den-crane))
- Fixed error while parsing of columns list from string if type contained a comma (this issue was relevant for `File`, `URL`, `HDFS` storages) [#6217](https://github.com/ClickHouse/ClickHouse/issues/6217). [#6209](https://github.com/ClickHouse/ClickHouse/pull/6209) ([dimarub2000](https://github.com/dimarub2000))