### ClickHouse release v21.3.9.83-lts FIXME as compared to v21.3.8.76-lts
#### Improvement
* Backported in [#23680](https://github.com/ClickHouse/ClickHouse/issues/23680): Fixed `quantile(s)TDigest`. Added special handling of singleton centroids according to tdunning/t-digest 3.2+. Also a bug with over-compression of centroids in implementation of earlier version of the algorithm was fixed. [#23314](https://github.com/ClickHouse/ClickHouse/pull/23314) ([Vladimir Chebotarev](https://github.com/excitoon)).
#### Bug Fix
* Backported in [#23579](https://github.com/ClickHouse/ClickHouse/issues/23579): Fixed very rare race condition on background cleanup of old blocks. It might cause a block not to be deduplicated if it's too close to the end of deduplication window. [#23301](https://github.com/ClickHouse/ClickHouse/pull/23301) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Backported in [#23677](https://github.com/ClickHouse/ClickHouse/issues/23677): Don't relax NOT conditions during partition pruning. This fixes [#23305](https://github.com/ClickHouse/ClickHouse/issues/23305) and [#21539](https://github.com/ClickHouse/ClickHouse/issues/21539). [#23310](https://github.com/ClickHouse/ClickHouse/pull/23310) ([Amos Bird](https://github.com/amosbird)).
* Backported in [#23582](https://github.com/ClickHouse/ClickHouse/issues/23582): * Fix bug in dict join with join_algorithm = 'auto'. Close [#23002](https://github.com/ClickHouse/ClickHouse/issues/23002). [#23312](https://github.com/ClickHouse/ClickHouse/pull/23312) ([Vladimir C](https://github.com/vdimir)).
* Backported in [#23585](https://github.com/ClickHouse/ClickHouse/issues/23585): Allow to move more conditions to `PREWHERE` as it was before version 21.1. Insufficient number of moved condtions could lead to worse performance. [#23397](https://github.com/ClickHouse/ClickHouse/pull/23397) ([Anton Popov](https://github.com/CurtizJ)).
* Backported in [#23592](https://github.com/ClickHouse/ClickHouse/issues/23592): Fixed `Cannot unlink file` error on unsuccessful creation of ReplicatedMergeTree table with multidisk configuration. This closes [#21755](https://github.com/ClickHouse/ClickHouse/issues/21755). [#23433](https://github.com/ClickHouse/ClickHouse/pull/23433) ([Alexander Tokmakov](https://github.com/tavplubix)).
* Backported in [#23590](https://github.com/ClickHouse/ClickHouse/issues/23590): Fix corner cases in vertical merges with `ReplacingMergeTree`. In rare cases they could lead to fails of merges with exceptions like `Incomplete granules are not allowed while blocks are granules size`. [#23459](https://github.com/ClickHouse/ClickHouse/pull/23459) ([Anton Popov](https://github.com/CurtizJ)).
* Backported in [#23696](https://github.com/ClickHouse/ClickHouse/issues/23696): Added an exception in case of completely the same values in both samples in aggregate function `mannWhitneyUTest`. This fixes [#23646](https://github.com/ClickHouse/ClickHouse/issues/23646). [#23654](https://github.com/ClickHouse/ClickHouse/pull/23654) ([Nikita Mikhaylov](https://github.com/nikitamikhaylov)).
