Project: ClickHouse (App Definition and Development / Database)
File: v21.5.2.25-prestable.md

sidebar_position: 1 sidebar_label: 2022 Backported in : Disable settings `usehedgedrequests` and `asyncsocketfor_remote` because there is an evidence that it may cause issues. (). Backported in : 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. (). Backported in : This PR fixes a crash on shutdown which happened because of currentConnections() could return zero while some connections were still alive. (). Backported in : QueryAliasVisitor to prefer alias for ASTWithAlias if subquery was optimized to constant. Fixes . Fixes . (). Backported in : Fixed `Not found column` error when selecting from `MaterializeMySQL` with condition on key column. Fixes . (). Backported in : Fixed the behavior when disabling `inputformatwithnamesuse_header ` setting discards all the input with CSVWithNames format. This fixes . (). Backported in : Add type conversion for optimizeskipunusedshardsrewritein (fixes `use-of-uninitialized-value` with `optimizeskipunusedshardsrewritein`). (). Backported in : Fixed simple key dictionary from DDL creation if primary key is not first attribute. Fixes . (). Backported in : Fixed very rare (distributed) race condition between creation and removal of ReplicatedMergeTree tables. It might cause exceptions like `node doesn't exist` on attempt to create replicated table. Fixes . (). Backported in : 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. (). Backported in : Fix possible crash in case if `unknown packet` was received form remote query (with `asyncsocketfor_remote` enabled). Maybe fixes . (). Backported in : Don't relax NOT conditions during partition pruning. This fixes and . (). Backported in : Fix bug in dict join with join_algorithm = 'auto'. Close . (). Backported in : Fix possible `Block structure mismatch` error for queries with `UNION` which could possibly happen after filter-push-down optimization. Fixes . (). Backported in : Fix incompatible constant expression generation during partition pruning based on virtual columns. This fixes https://github.com/ClickHouse/ClickHouse/pull/21401#discussion_r611888913. (). Backported in : `ORDER BY` with `COLLATE` was not working correctly if the column is in primary key (or is a monotonic function of it) and the setting `optimizereadinorder` is not turned off. This closes

Workaround for older versions: turn the setting `optimizereadinorder` off. (). Backported in : Remove support for `argMin` and `argMax` for single `Tuple` argument. The code was not memory-safe. The feature was added by mistake and it is confusing for people. These functions can be reintroduced under different names later. This fixes and reverts . (). Backported in : Allow to move more conditions to `PREWHERE` as it was before version 21.1. Insufficient number of moved condtions could lead to worse performance. (). Backported in : Kafka storage may support `arrow` and `arrowstream` format messages. (). Backported in : Fixed `Cannot unlink file` error on unsuccessful creation of ReplicatedMergeTree table with multidisk configuration. This closes . (). Backported in : - Bug fix for `deltaSum` aggregate function in counter reset case ... (). Backported in : Fix bug that does not allow cast from empty array literal, to array with dimensions greater than 1. Closes . (). Backported in : 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`. (). Backported in : When modify column's default value without datatype, and this column is used as ReplacingMergeTree's parameter like column `b` in the below example, then the server will core dump: ``` CREATE TABLE altertest (a Int32, b DateTime) ENGINE = ReplacingMergeTree(b) ORDER BY a; ALTER TABLE altertest MODIFY COLUMN `b` DEFAULT now(); ``` the sever throw error: ``` 2021.04.22 09:48:00.685317 (). Backported in : Fix `columns` function when multiple joins in select query. Closes . (). Backported in : Fix restart / stop command hanging. Closes . (). Backported in : Fix misinterpretation of some `LIKE` expressions with escape sequences. (). Backported in : Fixed server fault when inserting data through HTTP caused an exception. This fixes . (). Backported in : Added an exception in case of completely the same values in both samples in aggregate function `mannWhitneyUTest`. This fixes . (). Backported in : Avoid possible "Cannot schedule a task" error (in case some exception had been occurred) on INSERT into Distributed. (). Backported in :. (). Fix logical error in stress tests (). Zlib use attribute constructor for functable initialization (). Fix integration tests for Hedged requests (). System dictionaries virtual key column ().