Improvements

• Improve the performance of the UnionScanRead operator #32433
• Improve the display of task types in the output of EXPLAIN (add the MPP task type) #33332
• Support using rand() as the default value of a column #10377
• Support using uuid() as the default value of a column #33870
• Support modifying the character set of columns from latin1 to utf8/utf8mb4 #34008

Bug fixes

• Fix the issue of possible panic that might occur when the in function processes the bit type data #33070
• Fix the issue of wrong query result because the UnionScan operator cannot maintain the order #33175
• Fix the issue that the Merge Join operator gets wrong results in certain cases #33042
• Fix the issue that the index join result might be wrong in the dynamic pruning mode #33231
• Fix the issue that data might not be garbage-collected when some partitions of a partitioned table is dropped #33620
• Fix the issue that some DDL statements might be stuck for a period after the PD node of a cluster is replaced #33908
• Fix the issue that the TiDB server might run out of memory when the INFORMATION_SCHEMA.CLUSTER_SLOW_QUERY table is queried. This issue can be triggered when you check slow queries on the Grafana dashboard #33893
• Fix the issue that the system variable max_allowed_packet does not take effect #31422
• Fix the issue of memory leak in the TopSQL module #34525 #34502
• Fix the issue that the Plan Cache might be wrong on the PointGet plan #3237
• Fix the issue that query result might be wrong when Plan Cache is started in the RC isolation level #34447