TiDB 6.5.10 Release Notes

Release date: June 20, 2024

TiDB version: 6.5.10

Quick access: Quick start | Production deployment

Compatibility changes

• In earlier versions, when processing a transaction containing UPDATE changes, if the primary key or non-null unique index value is modified in an UPDATE event, TiCDC splits this event into DELETE and INSERT events. Starting from v6.5.10, when using the MySQL sink, TiCDC splits an UPDATE event into DELETE and INSERT events if the transaction commitTS for the UPDATE change is less than TiCDC thresholdTS (which is the current timestamp fetched from PD when TiCDC starts replicating the corresponding table to the downstream). This behavior change addresses the issue of downstream data inconsistencies caused by the potentially incorrect order of UPDATE events received by TiCDC, which can lead to an incorrect order of split DELETE and INSERT events. For more information, see documentation. #10918 @lidezhu
• Must set the line terminator when using TiDB Lightning strict-format to import CSV files #37338 @lance6716

Improvements

• TiDB

  • Improve the MySQL compatibility of expression default values displayed in the output of SHOW CREATE TABLE #52939 @CbcWestwolf
  • Remove stores without Regions during MPP load balancing #52313 @xzhangxian1008

• TiKV

  • Accelerate the shutdown speed of TiKV #16680 @LykxSassinator
  • Add monitoring metrics for the queue time for processing CDC events to facilitate troubleshooting downstream CDC event latency issues #16282 @hicqu

• Tools

  • Backup & Restore (BR)

    • BR cleans up empty SST files during data recovery #16005 @Leavrth
    • Increase the number of retries for failures caused by DNS errors #53029 @YuJuncen
    • Increase the number of retries for failures caused by the absence of a leader in a Region #54017 @Leavrth

  • TiCDC

    • Support directly outputting raw events when the downstream is a Message Queue (MQ) or cloud storage #11211 @CharlesCheung96
    • Improve memory stability during data recovery using redo logs to reduce the probability of OOM #10900 @CharlesCheung96
    • Significantly improve the stability of data replication in transaction conflict scenarios, with up to 10 times performance improvement #10896 @CharlesCheung96

Bug fixes

• TiDB

  • Fix the issue that querying metadata during statistics initialization might cause OOM #52219 @hawkingrei
  • Fix the issue that for tables containing auto-increment columns with AUTO_ID_CACHE=1, setting auto_increment_increment and auto_increment_offset system variables to non-default values might cause incorrect auto-increment ID allocation #52622 @tiancaiamao
  • Fix the issue that restoring a table with AUTO_ID_CACHE=1 using the RESTORE statement might cause a Duplicate entry error #52680 @tiancaiamao
  • Fix the issue that the STATE field in the INFORMATION_SCHEMA.TIDB_TRX table is empty due to the size of the STATE field not being defined #53026 @cfzjywxk
  • Fix the issue that TiDB does not create corresponding statistics metadata (stats_meta) when creating a table with foreign keys #53652 @hawkingrei
  • Fix the issue that the statistics synchronous loading mechanism might fail unexpectedly under high query concurrency #52294 @hawkingrei
  • Fix the issue that the Distinct_count information in GlobalStats might be incorrect when tidb_enable_async_merge_global_stats is disabled #53752 @hawkingrei
  • Fix the issue that the histogram and TopN in the primary key column statistics are not loaded after restarting TiDB #37548 @hawkingrei
  • Fix the issue that certain filter conditions in queries might cause the planner module to report an invalid memory address or nil pointer dereference error #53582 #53580 #53594 #53603 @YangKeao
  • Fix the issue that PREPARE/EXECUTE statements with the CONV expression containing a ? argument might result in incorrect query results when executed multiple times #53505 @qw4990
  • Fix the issue of incorrect WARNINGS information when using Optimizer Hints #53767 @hawkingrei
  • Fix the issue that the query latency of stale reads increases, caused by information schema cache misses #53428 @crazycs520
  • Fix the issue that DDL statements incorrectly use etcd and cause tasks to queue up #52335 @wjhuang2016
  • Fix the issue that internal columns are not renamed when executing RENAME INDEX to rename expression indexes #51431 @ywqzzy
  • Fix the issue that executing CREATE OR REPLACE VIEW concurrently might result in the table doesn't exist error #53673 @tangenta
  • Fix the issue that TiDB might panic when the JOIN condition contains an implicit type conversion #46556 @qw4990
  • Fix the issue that DDL operations get stuck due to network problems #47060 @wjhuang2016
  • Fix the issue that IndexJoin produces duplicate rows when calculating hash values in the Left Outer Anti Semi type #52902 @yibin87
  • Fix the issue that subqueries included in the ALL function might cause incorrect results #52755 @hawkingrei
  • Fix the issue that the TIMESTAMPADD() function returns incorrect results #41052 @xzhangxian1008
  • Fix the issue that TiDB might crash when tidb_mem_quota_analyze is enabled and the memory used by updating statistics exceeds the limit #52601 @hawkingrei
  • Fix the issue that subqueries in an UPDATE list might cause TiDB to panic #52687 @winoros
  • Fix the overflow issue of the Longlong type in predicates #45783 @hawkingrei
  • Fix the issue of inconsistent data indexes caused by concurrent DML operations when adding a unique index #52914 @wjhuang2016
  • Fix the issue that TiDB might panic when parsing index data #47115 @zyguan
  • Fix the issue that column pruning without using shallow copies of slices might cause TiDB to panic #52768 @winoros
  • Fix the issue that using a view does not work in recursive CTE #49721 @hawkingrei
  • Fix the issue that the LEADING hint does not support querying block aliases #44645 @qw4990
  • Fix the incorrect result of the TopN operator in correlated subqueries #52777 @yibin87
  • Fix the issue that unstable unique IDs of columns might cause the UPDATE statement to return errors #53236 @winoros
  • Fix the issue that TiDB keeps sending probe requests to a TiFlash node that has been offline #46602 @zyguan
  • Fix the issue that comparing a column of YEAR type with an unsigned integer that is out of range causes incorrect results #50235 @qw4990
  • Fix the issue that AutoID Leader change might cause the value of the auto-increment column to decrease in the case of AUTO_ID_CACHE=1 #52600 @tiancaiamao
  • Fix the issue that non-BIGINT unsigned integers might produce incorrect results when compared with strings/decimals #41736 @LittleFall
  • Fix the issue that data conversion from the FLOAT type to the UNSIGNED type returns incorrect results #41736 @guo-shaoge
  • Fix the issue that VAR_SAMP() cannot be used as a window function #52933 @hi-rustin
  • Fix the issue that a wrong TableDual plan causes empty query results #50051 @onlyacat
  • Fix the issue that the TiDB synchronously loading statistics mechanism retries to load empty statistics indefinitely and prints the fail to get stats version for this histogram log #52657 @hawkingrei
  • Fix the issue that an empty projection causes TiDB to panic #49109 @winoros
  • Fix the issue that the TopN operator might be pushed down incorrectly #37986 @qw4990
  • Fix the issue that TiDB panics when executing the SHOW ERRORS statement with a predicate that is always true #46962 @elsa0520
  • Fix the issue that the metadata lock fails to prevent DDL operations from executing in the plan cache scenario #51407 @wjhuang2016

• TiKV

  • Fix the issue that slow check-leader operations on one TiKV node cause resolved-ts on other TiKV nodes to fail to advance normally #15999 @crazycs520
  • Fix the issue that the CONV() function in queries might overflow during numeric system conversion, leading to TiKV panic #16969 @gengliqi
  • Fix the issue of unstable test cases, ensuring that each test uses an independent temporary directory to avoid online configuration changes affecting other test cases #16871 @glorv
  • Fix the issue that the decimal part of the DECIMAL type is incorrect in some cases #16913 @gengliqi
  • Fix the issue that resolve-ts is blocked when a stale Region peer ignores the GC message #16504 @crazycs520

• PD

  • Fix the issue that the Leader fails to transfer when you switch it between two deployed data centers #7992 @TonsnakeLin
  • Fix the issue that down peers might not recover when using Placement Rules #7808 @rleungx
  • Fix the issue that the Filter target monitoring metric for PD does not provide scatter range information #8125 @HuSharp

• TiFlash

  • Fix the issue that TiFlash might fail to synchronize schemas after executing ALTER TABLE ... EXCHANGE PARTITION across databases #7296 @JaySon-Huang
  • Fix the issue that a query with an empty key range fails to correctly generate read tasks on TiFlash, which might block TiFlash queries #9108 @JinheLin
  • Fix the issue that the SUBSTRING_INDEX() function might cause TiFlash to crash in some corner cases #9116 @wshwsh12
  • Fix the issue that TiFlash metadata might become corrupted and cause the process to panic when upgrading a cluster from a version earlier than v6.5.0 to v6.5.0 or later #9039 @JaySon-Huang
  • Fix the issue that TiFlash might return transiently incorrect results in high-concurrency read scenarios #8845 @JinheLin

• Tools

  • Backup & Restore (BR)

    • Fix the issue that the test case TestGetTSWithRetry takes too long to execute #52547 @Leavrth
    • Fix the issue that the Region fetched from PD does not have a Leader when restoring data using BR or importing data using TiDB Lightning in physical import mode #51124 #50501 @Leavrth
    • Fix the issue that a PD connection failure could cause the TiDB instance where the log backup advancer owner is located to panic #52597 @YuJuncen
    • Fix the issue that after pausing, stopping, and rebuilding the log backup task, the task status is normal, but the checkpoint does not advance #53047 @RidRisR
    • Fix the issue that data restore is slowed down due to the absence of a leader on a TiKV node #50566 @Leavrth
    • Fix the issue that the global checkpoint of log backup is advanced ahead of the actual backup file write point due to TiKV restart, which might cause a small amount of backup data loss #16809 @YuJuncen
    • Fix the issue that the transfer of PD leaders might cause BR to panic when restoring data #53724 @Leavrth
    • Fix the issue that TiKV might panic when resuming a paused log backup task with unstable network connections to PD #17020 @YuJuncen
    • Fix the issue that log backup might be paused after the advancer owner migration #53561 @RidRisR
    • Fix the issue that BR fails to correctly identify errors due to multiple nested retries during the restore process #54053 @RidRisR

  • TiCDC

    • Fix the issue that TiCDC fails to create a changefeed with Syncpoint enabled when the downstream database password is Base64 encoded #10516 @asddongmen
    • Fix the issue that DROP PRIMARY KEY and DROP UNIQUE KEY statements are not replicated correctly #10890 @asddongmen
    • Fix the issue that the default value of TIMEZONE type is not set according to the correct time zone #10931 @3AceShowHand

  • TiDB Lightning

    • Fix the issue that killing the PD Leader causes TiDB Lightning to report the invalid store ID 0 error during data import #50501 @Leavrth
    • Fix the issue of missing data in the TiDB Lightning Grafana dashboard #43357 @lichunzhu
    • Fix the issue that TiDB Lightning might print sensitive information to logs in server mode #36374 @kennytm
    • Fix the issue that TiDB fails to generate auto-increment IDs and reports an error Failed to read auto-increment value from storage engine after importing a table with both SHARD_ROW_ID_BITS and AUTO_ID_CACHE=1 set using TiDB Lightning #52654 @D3Hunter

  • Dumpling

    • Fix the issue that Dumpling reports an error when exporting tables and views at the same time #53682 @tangenta

  • TiDB Binlog

    • Fix the issue that deleting rows during the execution of ADD COLUMN might report an error data and columnID count not match when TiDB Binlog is enabled #53133 @tangenta