TiDB 6.5.7 Release Notes

Release date: January 8, 2024

TiDB version: 6.5.7

Quick access: Quick start | Production deployment

Compatibility changes

• Introduce the TiDB configuration item performance.force-init-stats to control whether TiDB needs to wait for statistics initialization to finish before providing services during TiDB startup #43385 @xuyifangreeneyes
• To reduce the overhead of log printing, TiFlash changes the default value of logger.level from "debug" to "info" #8568 @xzhangxian1008

Improvements

• TiDB

  • Optimize memory usage and performance for ANALYZE operations on partitioned tables #47071 #47104 #46804 @hawkingrei
  • Support Plan Cache to cache execution plans with the PointGet operator generated during physical optimization using Optimizer Fix Controls #44830 @qw4990
  • Enhance the ability to convert OUTER JOIN to INNER JOIN in specific scenarios #49616 @qw4990

• TiFlash

  • Reduce the impact of disk performance jitter on read latency #8583 @JaySon-Huang

• Tools

  • Backup & Restore (BR)

    • Improve the table creation performance of the RESTORE statement in scenarios with large datasets #48301 @Leavrth
    • Resolve compatibility issues between EBS-based snapshot backups and TiDB Lightning imports #46850 @YuJuncen
    • Alleviate the issue that the latency of the PITR log backup progress increases when Region leadership migration occurs #13638 @YuJuncen

  • TiCDC

    • When the downstream is Kafka, the topic expression allows schema to be optional and supports specifying a topic name directly #9763 @3AceShowHand

Bug fixes

• TiDB

  • Fix the issue that TiDB might not simultaneously create the new statistics metadata when a large number of CREATE TABLE statements are executed in a short period of time, causing subsequent query estimation to fail to get accurate row count information #36004 #38189 @xuyifangreeneyes
  • Fix the issue that TiDB server might consume a significant amount of resources when the enterprise plugin for audit logging is used #49273 @lcwangchao
  • Fix the incorrect error message for ErrLoadDataInvalidURI (invalid S3 URI error) #48164 @lance6716
  • Fix the issue that high CPU usage of TiDB occurs due to long-term memory pressure caused by tidb_server_memory_limit #48741 @XuHuaiyu
  • Fix the issue that queries containing common table expressions (CTEs) unexpectedly get stuck when the memory limit is exceeded #49096 @AilinKid
  • Fix the issue that the same query plan has different PLAN_DIGEST values in some cases #47634 @King-Dylan
  • Fix the issue that queries containing CTEs report runtime error: index out of range [32] with length 32 when tidb_max_chunk_size is set to a small value #48808 @guo-shaoge
  • Fix the issue that TiDB server might panic during graceful shutdown #36793 @bb7133
  • Fix the issue of possible statistics data errors when importing statistics exported from early versions of TiDB #42931 @xuyifangreeneyes
  • Fix the issue of excessive statistical error in constructing statistics caused by Golang's implicit conversion algorithm #49801 @qw4990
  • Fix the issue that the optimizer incorrectly converts TiFlash selection path to the DUAL table in specific scenarios #49285 @AilinKid
  • Fix the issue that parsing invalid values of ENUM or SET types would directly cause SQL statement errors #49487 @winoros
  • Fix the issue that UPDATE or DELETE statements containing WITH RECURSIVE CTEs might produce incorrect results #48969 @winoros
  • Fix the issue that using the _ wildcard in LIKE when the data contains trailing spaces can result in incorrect query results #48983 @time-and-fate
  • Fix the issue that a query containing the IndexHashJoin operator gets stuck when memory exceeds tidb_mem_quota_query #49033 @XuHuaiyu
  • Fix the issue that LIMIT and OPRDERBY might be invalid in nested UNION queries #49377 @AilinKid
  • Fix the issue that in non-strict mode (sql_mode = ''), truncation during executing INSERT still reports an error #49369 @tiancaiamao
  • Fix the issue that TiDB panics and reports an error invalid memory address or nil pointer dereference #42739 @CbcWestwolf
  • Fix the issue that CTE queries might report an error type assertion for CTEStorageMap failed during the retry process #46522 @tiancaiamao
  • Fix the issue that Daylight Saving Time is displayed incorrectly in some time zones #49586 @overvenus
  • Fix the issue that the completion times of two DDL tasks with dependencies are incorrectly sequenced #49498 @tangenta

• TiKV

  • Fix the issue that damaged SST files might be spread to other TiKV nodes #15986 @Connor1996
  • Fix the issue that Resolved TS in stale read might cause TiKV OOM issues when tracking large transactions #14864 @overvenus
  • Fix the issue that TiKV reports the ServerIsBusy error because it cannot append the raft log #15800 @tonyxuqqi

• PD

  • Fix the issue that the location-labels set by Placement Rules in SQL are not scheduled as expected under specific conditions #6637 @rleungx
  • Fix the issue that the orphan peer is deleted when the number of replicas does not meet the requirements #7584 @bufferflies

• TiFlash

  • Fix the issue that data of TiFlash replicas would still be garbage collected after executing FLASHBACK DATABASE #8450 @JaySon-Huang
  • Fix the issue of memory leak when TiFlash encounters memory limitation during query #8447 @JinheLin
  • Fix incorrect display of maximum percentile time for some panels in Grafana #8076 @JaySon-Huang
  • Fix the issue that the memory usage increases significantly due to slow queries #8564 @JinheLin

• Tools

  • Backup & Restore (BR)

    • Fix the issue that the log backup task can start but does not work properly if failing to connect to PD during task initialization #16056 @YuJuncen

  • TiCDC

    • Fix the issue that checkpoint-ts might get stuck when TiCDC replicates data to downstream MySQL #10334 @zhangjinpeng1987
    • Fix the potential data race issue during kv-client initialization #10095 @3AceShowHand