releases: add TiDB 4.0.5 release notes

TOC.md

@@ -508,6 +508,7 @@
 + Release Notes
   + [All Releases](/releases/release-notes.md)
   + v4.0
+    + [4.0.5](/releases/release-4.0.5.md)
     + [4.0.4](/releases/release-4.0.4.md)
     + [4.0.3](/releases/release-4.0.3.md)
     + [4.0.2](/releases/release-4.0.2.md)

releases/release-4.0.5.md

@@ -0,0 +1,175 @@
+---
+title: TiDB 4.0.5 Release Notes
+---
+
+# TiDB 4.0.5 Release Notes
+
+Release date: August 28, 2020
+
+TiDB version: 4.0.5
+
+## Compatibility Changes
+
++ TiDB
+
+    - Change `drop partition` and `truncate partition`'s job arguments to support the ID array of multiple partitions [#18930](https://github.com/pingcap/tidb/pull/18930)
+    - Add the delete-only state for checking `add partition` replicas [#18865](https://github.com/pingcap/tidb/pull/18865)
+
+## New Features
+
++ TiKV
+
+    - Define error code for errors [#8387](https://github.com/tikv/tikv/pull/8387)
+
++ TiFlash
+
+    - Support the unified log format with TiDB
+
++ Tools
+
+    + TiCDC
+
+        - Support Kafka SSL connection [#764](https://github.com/pingcap/ticdc/pull/764)
+        - Support outputting the old value [#708](https://github.com/pingcap/ticdc/pull/708)
+        - Add the column flags [#796](https://github.com/pingcap/ticdc/pull/796)
+        - Support outputting the DDL statements and table schema of the previous version [#799](https://github.com/pingcap/ticdc/pull/799)
+
+## Improvements
+
++ TiDB
+
+    - Optimize the performance of `DecodePlan` for big union queries [#18941](https://github.com/pingcap/tidb/pull/18941)
+    - Reduce the number of GC lock scans when meeting the `Region cache miss` error [#18876](https://github.com/pingcap/tidb/pull/18876)
+    - Ease the impact of statistical feedback on cluster performance [#18772](https://github.com/pingcap/tidb/pull/18772)
+    - Support canceling operations before the RPC response is returned [#18580](https://github.com/pingcap/tidb/pull/18580)
+    - Add the HTTP API to generate the TiDB metric profile [#18531](https://github.com/pingcap/tidb/pull/18531)
+    - Support scattering partitioned tables [#17863](https://github.com/pingcap/tidb/pull/17863)
+    - Add detailed memory usage of each instance in Grafana [#18679](https://github.com/pingcap/tidb/pull/18679)
+    - Show the detailed runtime information of the `BatchPointGet` operator in the result of `EXPLAIN` [#18892](https://github.com/pingcap/tidb/pull/18892)
+    - Show the detailed runtime information of the `PointGet` operator in the result of `EXPLAIN` [#18817](https://github.com/pingcap/tidb/pull/18817)
+    - Warn the potential deadlock for `Consume` in `remove()` [#18395](https://github.com/pingcap/tidb/pull/18395)
+    - Refine the behaviors of `StrToInt` and `StrToFloat` and support converting JSON to the `date`, `time`, and `timestamp` types [#18159](https://github.com/pingcap/tidb/pull/18159)
+    - Support limiting the memory usage of the `TableReader` operator [#18392](https://github.com/pingcap/tidb/pull/18392)
+    - Avoid too many times of backoff when retrying the `batch cop` request [#18999](https://github.com/pingcap/tidb/pull/18999)
+    - Improve compatibility for `ALTER TABLE` algorithms [#19270](https://github.com/pingcap/tidb/pull/19270)
+    - Make the single partitioned table support `IndexJoin` on the inner side [#19151](https://github.com/pingcap/tidb/pull/19151)
+    - Support searching the log file even when the log includes invalid lines [#18579](https://github.com/pingcap/tidb/pull/18579)
+
++ PD
+
+    - Support scattering Regions in stores with special engines (such as TiFlash) [#2706](https://github.com/tikv/pd/pull/2706)
+    - Support the Region HTTP API to prioritize Region scheduling of a given key range [#2687](https://github.com/tikv/pd/pull/2687)
+    - Improve the leader distribution after Region scattering [#2684](https://github.com/tikv/pd/pull/2684)
+    - Add more tests and logs for the TSO request [#2678](https://github.com/tikv/pd/pull/2678)
+    - Avoid invalid cache updates after the leader of a Region has changed [#2672](https://github.com/tikv/pd/pull/2672)
+    - Add an option to allow `store.GetLimit` to return the tombstone stores [#2743](https://github.com/tikv/pd/pull/2743)
+    - Support synchronizing the Region leader change between the PD leader and followers [#2795](https://github.com/tikv/pd/pull/2795)
+    - Add commands for querying the GC safepoint service [#2797](https://github.com/tikv/pd/pull/2797)
+    - Replace the `region.Clone` call in filters to improve performance [#2801](https://github.com/tikv/pd/pull/2801)
+    - Add an option to disable updating Region flow cache to improve the performance of the large cluster [#2848](https://github.com/tikv/pd/pull/2848)
+
++ TiFlash
+
+    - Add more Grafana panels to display metrics of CPU, I/O, RAM usages and metrics of the storage engine
+    - Reduce I/O operations by optimizing the processing logic of Raft logs
+    - Accelerate Region scheduling for the blocked `add partition` DDL statement
+    - Optimize compactions of delta data in DeltaTree to reduce read and write amplification
+    - Optimize the performance of applying Region snapshots by preprocessing the snapshots using multiple threads
+    - Optimize the number of opening file descriptors when the read load of TiFlash is low to reduce system resource consumption
+    - Optimize the number of unnecessary small files created when TiFlash restarts
+    - Support encryption at rest for data storage
+    - Support TLS for data transfer
+
++ Tools
+
+    + TiCDC
+
+        - Lower the frequency of getting TSO [#801](https://github.com/pingcap/ticdc/pull/801)
+
+    + Backup & Restore (BR)
+
+        - Optimize some logs [#428](https://github.com/pingcap/br/pull/428)
+
+    + Dumpling
+
+        - Release FTWRL after connections are created to reduce the lock time for MySQL [#121](https://github.com/pingcap/dumpling/pull/121)
+
+    + TiDB Lightning
+
+        - Optimize some logs [#352](https://github.com/pingcap/tidb-lightning/pull/352)
+
+## Bug Fixes
+
++ TiDB
+
+    - Fix the `should ensure all columns have the same length` error that occurs because the `ErrTruncate/Overflow` error is incorrectly handled in the `builtinCastRealAsDecimalSig` function [#18967](https://github.com/pingcap/tidb/pull/18967)
+    - Fix the issue that the `pre_split_regions` table option does not work in the partitioned table [#18837](https://github.com/pingcap/tidb/pull/18837)
+    - Fixe the issue that might cause a large transaction to be terminated prematurely [#18813](https://github.com/pingcap/tidb/pull/18813)
+    - Fix the issue that using the `collation` functions get wrong query results [#18735](https://github.com/pingcap/tidb/pull/18735)
+    - Fix the bug that the `getAutoIncrementID()` function does not consider the `tidb_snapshot` session variable, which might cause the dumper tool to fail with the `table not exist` error [#18692](https://github.com/pingcap/tidb/pull/18692)
+    - Fix the `unknown column error` for SQL statement like `select a from t having t.a` [#18434](https://github.com/pingcap/tidb/pull/18434)
+    - Fix the panic issue that writing the 64-bit unsigned type into the hash partitioned table causes overflow and gets an unexpected negative number when the partition key is the integer type [#18186](https://github.com/pingcap/tidb/pull/18186)
+    - Fix the wrong behavior of the `char` function [#18122](https://github.com/pingcap/tidb/pull/18122)
+    - Fix the issue that the `ADMIN REPAIR TABLE` statement cannot parse integer in the expressions on the range partition [#17988](https://github.com/pingcap/tidb/pull/17988)
+    - Fix the wrong behavior of the `SET CHARSET` statement [#17289](https://github.com/pingcap/tidb/pull/17289)
+    - Fix the bug caused by the wrong collation setting which leads to the wrong result of the `collation` function [#17231](https://github.com/pingcap/tidb/pull/17231)
+    - Fix the issue that `STR_TO_DATE`'s handling of the format tokens '%r', '%h' is inconsistent with that of MySQL [#18727](https://github.com/pingcap/tidb/pull/18727)
+    - Fix issues that the TiDB version information is inconsistent with that of PD/TiKV in the `cluster_info` table [#18413](https://github.com/pingcap/tidb/pull/18413)
+    - Fix the existent checks for pessimistic transactions [#19004](https://github.com/pingcap/tidb/pull/19004)
+    - Fix the issue that executing `union select for update` might cause concurrent race [#19006](https://github.com/pingcap/tidb/pull/19006)
+    - Fix the wrong query result when `apply` has a child of the `PointGet` operator [#19046](https://github.com/pingcap/tidb/pull/19046)
+    - Fix the incorrect result that occurs when `IndexLookUp` is in the inner side of the `Apply` operator [#19496](https://github.com/pingcap/tidb/pull/19496)
+    - Fix the incorrect result of `anti-semi-join` queries [#19472](https://github.com/pingcap/tidb/pull/19472)
+    - Fix the incorrect result caused by the mistaken usage of `BatchPointGet` [#19456](https://github.com/pingcap/tidb/pull/19456)
+    - Fix the incorrect result that occurs when `UnionScan` is in the inner side of the `Apply` operator [#19496](https://github.com/pingcap/tidb/pull/19496)
+    - Fix the panic caused by using the `EXECUTE` statement to print an expensive query log [#17419](https://github.com/pingcap/tidb/pull/17419)
+    - Fix the index join error when the join key is `ENUM` or `SET` [#19235](https://github.com/pingcap/tidb/pull/19235)
+    - Fix the issue that the query range cannot be built when the `NULL` value exists on the index column [#19358](https://github.com/pingcap/tidb/pull/19358)
+    - Fix the data race issue caused by updating the global configuration [#17964](https://github.com/pingcap/tidb/pull/17964)
+    - Fix the panic issue occurs when modifying the character set in an uppercase schema [#19286](https://github.com/pingcap/tidb/pull/19286)
+    - Fix an unexpected error caused by changing the temporary directory during the disk spill action [#18970](https://github.com/pingcap/tidb/pull/18970)
+    - Fix the wrong hash key for the decimal type [#19131](https://github.com/pingcap/tidb/pull/19131)
+    - Fix the issue that the `PointGet` and `BatchPointGet` operators do not consider the partition selection syntax and get incorrect results [#19141](https://github.com/pingcap/tidb/issues/19141)
+    - Fix the incorrect results when using the `Apply` operator together with the `UnionScan` operator [#19104](https://github.com/pingcap/tidb/issues/19104)
+    - Fix the bug that causes the indexed virtual generated column to return wrong value [#17989](https://github.com/pingcap/tidb/issues/17989)
+    - Add the lock for runtime statistics to fix a panic caused by concurrent execution [#18983](https://github.com/pingcap/tidb/pull/18983)
+
++ TiKV
+
+    - Speed up leader election when Hibernate Region is enabled [#8292](https://github.com/tikv/tikv/pull/8292)
+    - Fix the memory leak issue during scheduling [#8357](https://github.com/tikv/tikv/pull/8357)
+    - Add the `hibernate-timeout` configuration item to prevent the leader from becoming hibernate too fast [#8208](https://github.com/tikv/tikv/pull/8208)
+
++ PD
+
+    - Fix the bug that the TSO request might fail at the time of leader change [#2666](https://github.com/tikv/pd/pull/2666)
+    - Fix the issue that sometimes Region replicas cannot be scheduled to the optimal state when placement rules are enabled [#2720](https://github.com/tikv/pd/pull/2720)
+    - Fix the issue that `Balance Leader` does not work when placement rules are enabled [#2726](https://github.com/tikv/pd/pull/2726)
+    - Fix the issue that unhealthy stores are not filtered from store load statistics [#2805](https://github.com/tikv/pd/pull/2805)
+
++ TiFlash
+
+    - Fix the issue that TiFlash cannot start normally after upgrading from an earlier version if the name of the database or table contains special characters
+    - Fix the issue that the TiFlash process can not exit if any exceptions are thrown during initialization
+
++ Tools
+
+    + Backup & Restore (BR)
+
+        - Fix the issue of duplicated calculation of total KV and total bytes in the backup summary log [#472](https://github.com/pingcap/br/pull/472)
+        - Fix the issue that the import mode does not work in the first 5 minutes after switching to this mode [#473](https://github.com/pingcap/br/pull/473)
+
+    + Dumpling
+
+        - Fix the issue that FTWRL lock is not released in time [#128](https://github.com/pingcap/dumpling/pull/128)
+
+    + TiCDC
+
+        - Fix the issue that the failed `changefeed` cannot be removed [#782](https://github.com/pingcap/ticdc/pull/782)
+        - Fix invalid `delete` events by selecting one unique index as the handle index [#787](https://github.com/pingcap/ticdc/pull/787)
+        - Fix the bug that GC safepoint is forwarded beyond the checkpoint of stopped `changefeed` [#797](https://github.com/pingcap/ticdc/pull/797)
+        - Fix the bug that the network I/O waiting blocks tasks to exit [#825](https://github.com/pingcap/ticdc/pull/825)
+
+    + TiDB Lightning
+
+        - Fix the syntax error on empty binary/hex literals when using TiDB backend [#357](https://github.com/pingcap/tidb-lightning/pull/357)

releases/release-notes.md

@@ -7,6 +7,7 @@ aliases: ['/docs/dev/releases/release-notes/','/docs/dev/releases/rn/']
 
 ## 4.0
 
+- [4.0.5](/releases/release-4.0.5.md)
 - [4.0.4](/releases/release-4.0.4.md)
 - [4.0.3](/releases/release-4.0.3.md)
 - [4.0.2](/releases/release-4.0.2.md)