v6.2.0

release notes

Published 8/23/2022

MinorContains breaking changes

Release notes

For the complete and official release notes, see https://docs.pingcap.com/tidb/v6.2/release-6.2.0.

Improvements

Support the SHOW COUNT(*) WARNINGS and SHOW COUNT(*) ERRORS statements #25068 @likzn
Add validation check for some system variables #35048 @morgo
Optimize the error messages for some type conversions #32447 @fanrenhoo
The KILL command now supports DDL operations #24144 @morgo
Make the output of SHOW TABLES/DATABASES LIKE … more MySQL-compatible. The column names in the output contain the LIKE value #35116 @likzn
Improve the performance of JSON-related functions #35859 @wjhuang2016
Improve the verification speed of password login using SHA-2 #35998 @virusdefender
Simplify some log outputs #36011 @dveeden
Optimize the Coprocessor communication protocol. This can greatly reduce the memory consumption of the TiDB processes when reading data, and further alleviate the OOM issue in the scenario of scanning tables and exporting data by Dumpling. The system variable tidb_enable_paging is introduced to control whether to enable this communication protocol (with the scope of SESSION or GLOBAL). This protocol is disabled by default. To enable it, set the variable value to true #35633 @tiancaiama @wshwsh12
Optimize the accuracy of memory tracking for some operators (HashJoin, HashAgg, Update, Delete) (#35634, #35631, #35635 @wshwsh12) (#34096 @ekexium)
The system table INFORMATION_SCHEMA.DATA_LOCK_WAIT supports recording the locking information of optimistic transactions #34609 @longfangson
Add some monitoring metrics for transactions #34456 @longfangsong
...

Bug fixes

Fix the issue that a partition is incorrectly pruned if a partition key is used in the query condition and the collate is different from the one in the query partition table #32749 @mjonss
Fix the issue that SET ROLE cannot match the granted role if there are capital letters in the host #33061 @morgo
Fix the issue that columns with auto_increment cannot be dropped #34891 @Defined2014
Fix the issue that SHOW CONFIG shows some configuration items that have been removed #34867 @morgo
Fix the issue that SHOW DATABASES LIKE … is case-sensitive #34766 @e11jah
Fix the issue that SHOW TABLE STATUS LIKE ... is case-sensitive #7518 @likzn
Fix the issue that max-index-length still reports an error in non-strict mode #34931 @e11jah
Fix the issue that ALTER COLUMN ... DROP DEFAULT does not work #35018 @Defined2014
Fix the issue that when you create a table, the default value and the type of a column are not consistent and are not automatically corrected #34881 @Lloyd-Pottiger
Fix the issue that data in the mysql.columns_priv table is not deleted synchronously after you run DROP USER #35059 @lcwangchao
Fix the issue of DDL jam by disallowing creating tables within the schemas of some systems #35205 @tangenta
Fix the issue that querying partitioned tables might report "index-out-of-range" and "non used index" errors in some cases #35181 @mjonss
Fix the issue that INTERVAL expr unit + expr might report an error #30253 @mjonss
Fix a bug that a temporary table cannot be found after being created in a transaction #35644 @djshow832
Fix the panic issue that occurs when setting collation to the ENUM column #31637 @wjhuang2016
Fix the issue that when one PD node goes down, the query of information_schema.TIKV_REGION_STATUS fails due to not retrying other PD nodes #35708 @tangenta
Fix the issue that SHOW CREATE TABLE … cannot correctly display set or ENUM columns after SET character_set_results = GBK #31338 @tangenta
Fix the incorrect scope of the system variables tidb_log_file_max_days and tidb_config #35190 @morgo
Fix the issue that the output of SHOW CREATE TABLE is not compatible with MySQL for the ENUM or SET column #36317 @Defined2014
Fix the issue that when creating a table, the behavior of a LONG BYTE column is not compatible with MySQL #36239 @Defined2014
Fix the issue that auto_increment = x does not take effect on temporary tables #36224 @djshow832
Fix the wrong default value when modifying columns concurrently #35846 @wjhuang2016
Avoid sending requests to unhealthy TiKV nodes to improve availability #34906 @sticnarf
Fix the issue that the column list does not work in the LOAD DATA statement #35198 @SpadeA-Tang
Fix the issue that in some scenarios the pessimistic lock is incorrectly added to the non-unique secondary index #36235 @ekexium
...

Improvements

Support the SHOW COUNT(*) WARNINGS and SHOW COUNT(*) ERRORS statements #25068 @likzn

Add validation check for some system variables #35048 @morgo

Optimize the error messages for some type conversions #32447 @fanrenhoo

The KILL command now supports DDL operations #24144 @morgo

Make the output of SHOW TABLES/DATABASES LIKE … more MySQL-compatible. The column names in the output contain the LIKE value #35116 @likzn

Improve the performance of JSON-related functions #35859 @wjhuang2016

Improve the verification speed of password login using SHA-2 #35998 @virusdefender

Simplify some log outputs #36011 @dveeden

Optimize the Coprocessor communication protocol. This can greatly reduce the memory consumption of the TiDB processes when reading data, and further alleviate the OOM issue in the scenario of scanning tables and exporting data by Dumpling. The system variable tidb_enable_paging is introduced to control whether to enable this communication protocol (with the scope of SESSION or GLOBAL). This protocol is disabled by default. To enable it, set the variable value to true #35633 @tiancaiama @wshwsh12

Optimize the accuracy of memory tracking for some operators (HashJoin, HashAgg, Update, Delete) (#35634, #35631, #35635 @wshwsh12) (#34096 @ekexium)

The system table INFORMATION_SCHEMA.DATA_LOCK_WAIT supports recording the locking information of optimistic transactions #34609 @longfangson

Add some monitoring metrics for transactions #34456 @longfangsong

...

Bug fixes

Fix the issue that a partition is incorrectly pruned if a partition key is used in the query condition and the collate is different from the one in the query partition table #32749 @mjonss

Fix the issue that SET ROLE cannot match the granted role if there are capital letters in the host #33061 @morgo

Fix the issue that columns with auto_increment cannot be dropped #34891 @Defined2014

Fix the issue that SHOW CONFIG shows some configuration items that have been removed #34867 @morgo

Fix the issue that SHOW DATABASES LIKE … is case-sensitive #34766 @e11jah

Fix the issue that SHOW TABLE STATUS LIKE ... is case-sensitive #7518 @likzn

Fix the issue that max-index-length still reports an error in non-strict mode #34931 @e11jah

Fix the issue that ALTER COLUMN ... DROP DEFAULT does not work #35018 @Defined2014

Fix the issue that when you create a table, the default value and the type of a column are not consistent and are not automatically corrected #34881 @Lloyd-Pottiger

Fix the issue that data in the mysql.columns_priv table is not deleted synchronously after you run DROP USER #35059 @lcwangchao

Fix the issue of DDL jam by disallowing creating tables within the schemas of some systems #35205 @tangenta

Fix the issue that querying partitioned tables might report "index-out-of-range" and "non used index" errors in some cases #35181 @mjonss

Fix the issue that INTERVAL expr unit + expr might report an error #30253 @mjonss

Fix a bug that a temporary table cannot be found after being created in a transaction #35644 @djshow832

Fix the panic issue that occurs when setting collation to the ENUM column #31637 @wjhuang2016

Fix the issue that when one PD node goes down, the query of information_schema.TIKV_REGION_STATUS fails due to not retrying other PD nodes #35708 @tangenta

Fix the issue that SHOW CREATE TABLE … cannot correctly display set or ENUM columns after SET character_set_results = GBK #31338 @tangenta

Fix the incorrect scope of the system variables tidb_log_file_max_days and tidb_config #35190 @morgo

Fix the issue that the output of SHOW CREATE TABLE is not compatible with MySQL for the ENUM or SET column #36317 @Defined2014

Fix the issue that when creating a table, the behavior of a LONG BYTE column is not compatible with MySQL #36239 @Defined2014

Fix the issue that auto_increment = x does not take effect on temporary tables #36224 @djshow832

Fix the wrong default value when modifying columns concurrently #35846 @wjhuang2016

Avoid sending requests to unhealthy TiKV nodes to improve availability #34906 @sticnarf

Fix the issue that the column list does not work in the LOAD DATA statement #35198 @SpadeA-Tang

Fix the issue that in some scenarios the pessimistic lock is incorrectly added to the non-unique secondary index #36235 @ekexium