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sidebar_label: 2022
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# 2022 Changelog

### ClickHouse release v21.5.9.4-stable FIXME as compared to v21.5.8.21-stable

#### Bug Fix
* Backported in [#25958](https://github.com/ClickHouse/ClickHouse/issues/25958): Fix extremely long backoff for background tasks when the background pool is full. Fixes [#25836](https://github.com/ClickHouse/ClickHouse/issues/25836). [#25893](https://github.com/ClickHouse/ClickHouse/pull/25893) ([alesapin](https://github.com/alesapin)).
* Backported in [#26144](https://github.com/ClickHouse/ClickHouse/issues/26144): Fix possible crash in `pointInPolygon` if the setting `validate_polygons` is turned off. [#26113](https://github.com/ClickHouse/ClickHouse/pull/26113) ([Alexey Milovidov](https://github.com/alexey-milovidov)).

#### NOT FOR CHANGELOG / INSIGNIFICANT

* 21.5 manual backport of [#25970](https://github.com/ClickHouse/ClickHouse/issues/25970) [#26139](https://github.com/ClickHouse/ClickHouse/pull/26139) ([Maksim Kita](https://github.com/kitaisreal)).
* 21.5 Docker unbundled fix [#26154](https://github.com/ClickHouse/ClickHouse/pull/26154) ([Maksim Kita](https://github.com/kitaisreal)).