pingcap/tidb v5.1.1

tidb-server v5.1.1

on GitHub

Compatibility changes

• For TiDB clusters upgrade from v4.0 to v5.1, the default value of tidb_multi_statement_mode is OFF. It is recommended to use the multi-statement feature of your client library instead. See the documentation on tidb_multi_statement_mode for details. #25751
• Change the default value of the tidb_stmt_summary_max_stmt_count variable from 200 to 3000 #25874
• Require the SUPER privilege to access the table_storage_stats table #26352
• Require the SELECT privilege on mysql.user to access the information_schema.user_privileges table to show other user's privileges #26311
• Require the CONFIG privilege to access the information_schema.cluster_hardware table #26297
• Require the PROCESS privilege to access the information_schema.cluster_info table #26297
• Require the PROCESS privilege to access the information_schema.cluster_load table #26297
• Require the PROCESS privilege to access the information_schema.cluster_systeminfo table #26297
• Require the PROCESS privilege to access the information_schema.cluster_log table #26297
• Require the CONFIG privilege to access the information_schema.cluster_config table #26150

Improvements

• Announce the general availability (GA) of the Stale Read feature
• Avoid allocation for paramMarker to speed up data insertion #26076
• Support the stable result mode to make the query results more stable #25995
• Support pushing down the built-in function json_unquote() to TiKV #26265
• Support retrying MPP queries #26480
• Change the LOCK record into the PUT record for the index keys using point get or batch point get for UPDATE reads #26225
• Forbid creating views from stale queries #26200
• Thoroughly push down the COUNT(DISTINCT) aggregation function in the MPP mode #26194
• Check the availability of TiFlash before launching MPP queries #26192
• Do not allow setting the read timestamp to a future time #25763
• Print log warnings when aggregation functions cannot be pushed down in EXPLAIN statements #25737
• Add the statements_summary_evicted table to record the evicted count information of a cluster #25587
• Improve the MySQL compatibility of the built-in function str_to_date for the format specifiers %b/%M/%r/%T #25768

Bug fixes

• Fix the data loss issue that might occur when changing the column type with tidb_enable_amend_pessimistic_txn=on #26203
• Fix the issue that the behavior of the last_day function is incompatible in the SQL mode #26001
• Fix the panic issue that might occur when LIMIT is on top of window functions #25344
• Fix the issue that committing pessimistic transactions might cause write conflict #25964
• Fix the issue that the result of index join in correlated subqueries is wrong #25799
• Fix a bug that the successfully committed optimistic transactions might report commit errors #10468
• Fix the issue that an incorrect result is returned when using merge join on the SET type column #25669
• Fix a bug that the index keys in a pessimistic transaction might be repeatedly committed #26359
• Fix the risk of integer overflow when the optimizer is locating partitions #26227
• Fix the issue that invalid values might be written when casting DATE to timestamp #26292
• Fix the issue that the Coprocessor Cache metrics are not displayed on Grafana #26338
• Fix the issue of annoying logs caused by telemetry #25760 #25785
• Fix a bug on the query range of prefix index #26029
• Fix the issue that concurrently truncating the same partition hangs DDL executions #26229
• Fix the issue of duplicate ENUM items #25955
• Fix a bug that the CTE iterator is not correctly closed #26112
• Fix the issue that the LOAD DATA statement might abnormally import non-utf8 data #25979
• Fix the panic issue that might occur when using the window function on the unsigned integer columns #25956
• Fix the issue that TiDB might panic when resolving async commit locks #25778
• Fix the issue that Stale Read is not fully compatible with the PREPARE statements #25800
• Fix the issue that the ODBC-styled constant (for example, {d '2020-01-01'}) cannot be used as the expression #25531
• Fix an error that occurs when running TiDB alone #25555