TiDB 6.5.3 Release Notes

Release date: June 14, 2023

TiDB version: 6.5.3

Quick access: Quick start | Production deployment

Compatibility changes

Behavior changes

• When processing update event, TiCDC splits an event into delete and insert events if the primary key or non-null unique index value is modified in the event. For more information, see documentation.

Improvements

• TiDB

  • Improve the performance of TRUNCATE on partitioned tables with Placement Rules #43070 @Lloyd-Pottiger
  • Avoid invalid Stale Read retries after resolving locks #43659 @you06
  • Reduce latency by using leader read when Stale Read encounters the DataIsNotReady error #765 @Tema
  • Add Stale Read OPS and Stale Read MBps metrics to track hit rate and traffic when using Stale Read #43325 @you06

• TiKV

  • Reduce traffic by using gzip to compress check_leader requests #14839 @cfzjywxk

• PD

  • Use a separate gRPC connection for PD leader election to prevent the impact of other requests #6403 @rleungx

• Tools

  • TiCDC

    • Optimize the way TiCDC handles DDLs so that DDLs do not block the use of other unrelated DML Events, and reduce memory usage #8106 @asddongmen
    • Optimize the Decoder interface and add a new method AddKeyValue #8861 @3AceShowHand
    • Optimize the directory structure when DDL events occur in the scenario of replicating data to object storage #8890 @CharlesCheung96
    • Support replicating data to the Kafka-on-Pulsar downstream #8892 @hi-rustin
    • Support using the OAuth protocol for validation when replicating data to Kafka #8865 @hi-rustin
    • Optimize the way TiCDC handles the UPDATE statement during data replication using the Avro or CSV protocol, by splitting UPDATE into DELETE and INSERT statements, so that you can get the old value from the DELETE statement #9086 @3AceShowHand
    • Add a configuration item insecure-skip-verify to control whether to set the authentication algorithm in the scenario of enabling TLS #8867 @hi-rustin
    • Optimize DDL replication operations to mitigate the impact of DDL operations on downstream latency #8686 @hi-rustin
    • Optimize the method of setting GC TLS for the upstream when the TiCDC replication task fails #8403 @charleszheng44

  • TiDB Binlog

    • Optimize the method of retrieving table information to reduce the initialization time and memory usage of Drainer #1137 @lichunzhu

Bug fixes

• TiDB

  • Fix the issue that the min, max query result is incorrect #43805 @wshwsh12
  • Fix the issue of incorrect execution plans when pushing down window functions to TiFlash #43922 @gengliqi
  • Fix the issue that the query with CTE causes TiDB to hang #43749 #36896 @guo-shaoge
  • Fix the issue that the SQL statement reports the runtime error: index out of range error when using the AES_DECRYPT expression #43063 @lcwangchao
  • Fix the issue that the SHOW PROCESSLIST statement cannot display the TxnStart of the transaction of the statement with a long subquery time #40851 @crazycs520
  • Fix the issue that PD isolation might block the running DDL #44014 #43755 #44267 @wjhuang2016
  • Fix the TiDB panic issue that occurs when querying union views and temporary tables with UNION #42563 @lcwangchao
  • Fix the behavior issue of Placement Rules in partitioned tables, so that the Placement Rules in deleted partitions can be correctly set and recycled #44116 @lcwangchao
  • Fix the issue that truncating a partition of a partitioned table might cause the Placement Rule of the partition to become invalid #44031 @lcwangchao
  • Fix the issue that TiCDC might lose some row changes during table renaming #43338 @tangenta
  • Fix the issue that the DDL job history is lost after importing a table using BR #43725 @tangenta
  • Fix the issue that JSON_OBJECT might report an error in some cases #39806 @YangKeao
  • Fix the issue that the cluster cannot query some system views in IPv6 environment #43286 @Defined2014
  • Fix the issue that when the PD member address changes, allocating ID for the AUTO_INCREMENT column will be blocked for a long time #42643 @tiancaiamao
  • Fix the issue that TiDB sends duplicate requests to PD during placement rules recycling, causing numerous full config reset entries in the PD log #33069 @tiancaiamao
  • Fix the issue that the SHOW PRIVILEGES statement returns an incomplete privilege list #40591 @CbcWestwolf
  • Fix the issue that ADMIN SHOW DDL JOBS LIMIT returns incorrect results #42298 @CbcWestwolf
  • Fix the issue that the tidb_auth_token user fails to be created when the password complexity check is enabled #44098 @CbcWestwolf
  • Fix the issue of not finding the partition during inner join in dynamic pruning mode #43686 @mjonss
  • Fix the issue that the Data Truncated warning occurs when executing MODIFY COLUMN on a partitioned table #41118 @mjonss
  • Fix the issue of displaying the incorrect TiDB address in IPv6 environment #43260 @nexustar
  • Fix the issue that CTE results are incorrect when pushing down predicates #43645 @winoros
  • Fix the issue that incorrect results might be returned when using a common table expression (CTE) in statements with non-correlated subqueries #44051 @winoros
  • Fix the issue that Join Reorder might cause incorrect outer join results #44314 @AilinKid
  • Fix the issue that in some extreme cases, when the first statement of a pessimistic transaction is retried, resolving locks on this transaction might affect transaction correctness #42937 @MyonKeminta
  • Fix the issue that in some rare cases, residual pessimistic locks of pessimistic transactions might affect data correctness when GC resolves locks #43243 @MyonKeminta
  • Fix the issue that the scan detail information during the execution of batch cop might be inaccurate #41582 @you06
  • Fix the issue that TiDB cannot read data updates when Stale Read and PREPARE statements are used at the same time #43044 @you06
  • Fix the issue that an assertion failed error might be mistakenly reported when executing the LOAD DATA statement #43849 @you06
  • Fix the issue that the coprocessor cannot fall back to the leader when a region data not ready error occurs during the use of Stale Read #43365 @you06

• TiKV

  • Fix the issue that the peers of the corresponding Region mistakenly hibernate when a TiKV node fails #14547 @hicqu
  • Fix the issue of file handle leakage in Continuous Profiling #14224 @tabokie
  • Fix the issue that PD crash might cause PITR to fail to proceed #14184 @YuJuncen
  • Fix the issue that encryption key ID conflict might cause the deletion of the old keys #14585 @tabokie
  • Fix the issue that autocommit and point get replica read might break linearizability #14715 @cfzjywxk
  • Fix the performance degradation issue caused by accumulated lock records when a cluster is upgraded from a previous version to v6.5 or later versions #14780 @MyonKeminta
  • Fix the issue that TiDB Lightning might cause SST file leakage #14745 @YuJuncen
  • Fix the potential conflict between the encryption key and raft log file deletion that might cause TiKV to fail to start #14761 @Connor1996

• TiFlash

  • Fix the performance degradation issue of the partition TableScan operator during Region transfer #7519 @Lloyd-Pottiger
  • Fix the issue that a TiFlash query might report an error if the GENERATED type field is present along with the TIMESTAMP or TIME type #7468 @Lloyd-Pottiger
  • Fix the issue that large update transactions might cause TiFlash to repeatedly report errors and restart #7316 @JaySon-Huang
  • Fix the issue that the error "Truncate error cast decimal as decimal" occurs when reading data from TiFlash with the INSERT SELECT statement #7348 @windtalker
  • Fix the issue that queries might consume more memory than needed when the data on the Join build side is very large and contains many small string type columns #7416 @yibin87

• Tools

  • Backup & Restore (BR)

    • Fix the issue that the error message "resolve lock timeout" of BR is misleading when a backup fails, which hides the actual error information #43236 @YuJuncen

  • TiCDC

    • Fix an OOM issue that might occur when there are as many as 50,000 tables #7872 @sdojjy
    • Fix the issue that TiCDC gets stuck when an OOM occurs in upstream TiDB #8561 @overvenus
    • Fix the issue that TiCDC gets stuck when PD fails such as network isolation or PD Owner node reboot #8808 #8812 #8877 @asddongmen
    • Fix the issue of TiCDC time zone setting #8798 @hi-rustin
    • Fix the issue that checkpoint lag increases when one of the upstream TiKV nodes crashes #8858 @hicqu
    • Fix the issue that when replicating data to downstream MySQL, a replication error occurs after the FLASHBACK CLUSTER TO TIMESTAMP statement is executed in the upstream TiDB #8040 @asddongmen
    • Fix the issue that when replicating data to object storage, the EXCHANGE PARTITION operation in the upstream cannot be properly replicated to the downstream #8914 @CharlesCheung96
    • Fix the OOM issue caused by excessive memory usage of the sorter component in some special scenarios #8974 @hicqu
    • Fix the issue that when the downstream is Kafka, TiCDC queries the downstream metadata too frequently and causes excessive workload in the downstream #8957 #8959 @hi-rustin
    • Fix the issue that when a replication error occurs due to an oversized Kafka message, the message body is recorded in the log #9031 @darraes
    • Fix the TiCDC node panic that occurs when the downstream Kafka sinks are rolling restarted #9023 @asddongmen
    • Fix the issue that when replicating data to storage services, the JSON file corresponding to downstream DDL statements does not record the default values of table fields #9066 @CharlesCheung96

  • TiDB Lightning

    • Fix the issue that OOM might occur when importing a wide table #43728 @D3Hunter
    • Fix the issue of write to tikv with no leader returned when importing a large amount of data #43055 @lance6716
    • Fix a possible OOM problem when there is an unclosed delimiter in the data file #40400 @buchuitoudegou
    • Add a retry mechanism when encountering an unknown RPC error during data import #43291 @D3Hunter

  • TiDB Binlog

    • Fix the issue that TiDB Binlog reports an error when encountering a CANCELED DDL statement #1228 @okJiang