TiDB 7.1.5 Release Notes

Release date: April 26, 2024

TiDB version: 7.1.5

Quick access: Quick start | Production deployment

Compatibility changes

• Add a TiKV configuration item track-and-verify-wals-in-manifest for RocksDB, which helps you investigate possible corruption of Write Ahead Log (WAL) #16549 @v01dstar

Improvements

• TiDB

  • Support loading Regions in batch from PD to speed up the conversion process from the KV range to Regions when querying large tables #51326 @SeaRise
  • Optimize the issue that the ANALYZE statement blocks the metadata lock #47475 @wjhuang2016
  • Add a timeout mechanism for LDAP authentication to avoid the issue of resource lock (RLock) not being released in time #51883 @YangKeao

• TiKV

  • Add slow logs for peer and store messages #16600 @Connor1996
  • Avoid performing IO operations on snapshot files in raftstore threads to improve TiKV stability #16564 @Connor1996

• PD

  • Upgrade the etcd version to v3.4.30 #7904 @JmPotato

• Tools

  • Backup & Restore (BR)

    • Support automatically abandoning log backup tasks when encountering a large checkpoint lag, to avoid prolonged blocking GC and potential cluster issues #50803 @RidRisR
    • Add PITR integration test cases to cover compatibility testing for log backup and adding index acceleration #51987 @Leavrth
    • Remove the invalid verification for active DDL jobs when log backup starts #52733 @Leavrth

Bug fixes

• TiDB

  • Fix the issue that querying JSON of BINARY type might cause an error in some cases #51547 @YangKeao
  • Fix the issue that query execution using MPP might lead to incorrect query results when a SQL statement contains JOIN and the SELECT list in the statement contains only constants #50358 @yibin87
  • Fix the issue that the init-stats process might cause TiDB to panic and the load stats process to quit #51581 @hawkingrei
  • Fix the issue that the TiDB server is marked as health before the initialization is complete #51596 @shenqidebaozi
  • Fix the issue that ALTER TABLE ... COMPACT TIFLASH REPLICA might incorrectly end when the primary key type is VARCHAR #51810 @breezewish
  • Fix the issue that TiDB crashes when shuffleExec quits unexpectedly #48230 @wshwsh12
  • Fix the issue that the SURVIVAL_PREFERENCES attribute might not appear in the output of the SHOW CREATE PLACEMENT POLICY statement under certain conditions #51699 @lcwangchao
  • Fix the issue that after the time window for automatic statistics updates is configured, statistics might still be updated outside that time window #49552 @hawkingrei
  • Fix the issue that query results might be incorrect when the HAVING clause in a subquery contains correlated columns #51107 @hawkingrei
  • Fix the issue that the approx_percentile function might cause TiDB panic #40463 @xzhangxian1008
  • Fix the issue that the query result is incorrect when the IN() predicate contains NULL #51560 @winoros
  • Fix the issue that the configuration file does not take effect when it contains an invalid configuration item #51399 @Defined2014
  • Fix the issue that EXCHANGE PARTITION incorrectly processes foreign keys #51807 @YangKeao
  • Fix the issue that querying the TIDB_HOT_REGIONS table might incorrectly return INFORMATION_SCHEMA tables #50810 @Defined2014
  • Fix the issue that the type returned by the IFNULL function is inconsistent with MySQL #51765 @YangKeao
  • Fix the issue that the TTL feature causes data hotspots due to incorrect data range splitting in some cases #51527 @lcwangchao
  • Fix the issue that TiDB keeps sending probe requests to a TiFlash node that has been offline #46602 @zyguan
  • 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 executing INSERT IGNORE might result in inconsistency between the unique index and the data #51784 @wjhuang2016
  • Fix the issue that adding a unique index might cause TiDB to panic #52312 @wjhuang2016
  • Fix the issue that the Window function might panic when there is a related subquery in it #42734 @hi-rustin
  • Fix the issue that the init-stats process might cause TiDB to panic and the load stats process to quit #51581 @hawkingrei
  • Fix the performance regression issue caused by disabling predicate pushdown in TableDual #50614 @time-and-fate
  • Fix the issue that query results might be incorrect when the HAVING clause in a subquery contains correlated columns #51107 @hawkingrei
  • Fix the issue that the EXPLAIN statement might display incorrect column IDs in the result when statistics for certain columns are not fully loaded #52207 @time-and-fate

• TiKV

  • Fix the issue that resolve-ts is blocked when a stale Region peer ignores the GC message #16504 @crazycs520
  • Fix the issue that inactive Write Ahead Logs (WALs) in RocksDB might corrupt data #16705 @Connor1996
  • Fix the issue that the monitoring metric tikv_unified_read_pool_thread_count has no data in some cases #16629 @YuJuncen
  • Fix the issue that during the execution of an optimistic transaction, if other transactions initiate the resolving lock operation on it, there is a small chance that the atomicity of the transaction might be broken if the transaction’s primary key has data that was previously committed in Async Commit or 1PC mode #16620 @MyonKeminta

• PD

  • Fix the issue that the scheduling of write hotspots might break placement policy constraints #7848 @lhy1024
  • Fix the issue that the query result of SHOW CONFIG includes the deprecated configuration item trace-region-flow #7917 @rleungx
  • Fix the issue that the scaling progress is not correctly displayed #7726 @CabinfeverB

• TiFlash

  • Fix incorrect local_region_num values in logs #8895 @JaySon-Huang
  • Fix the issue that querying generated columns returns an error #8787 @guo-shaoge
  • Fix the issue that the ENUM column might cause TiFlash to crash during chunk encoding #8674 @yibin87
  • Fix the issue that TiFlash might panic when you insert data to columns with invalid default values in non-strict sql_mode #8803 @Lloyd-Pottiger
  • Fix the issue that if Region migration, split, or merge occurs after the precision of a TIME column is modified, queries might fail #8601 @JaySon-Huang

• Tools

  • Backup & Restore (BR)

    • Fix the issue that removing a log backup task after it is paused does not immediately restore the GC safepoint #52082 @3pointer
    • Fix the issue that too many logs are printed when a full backup fails #51572 @Leavrth
    • Fix the issue that BR could not back up the AUTO_RANDOM ID allocation progress if the AUTO_RANDOM column is in a composite clustered index #52255 @Leavrth
    • Fix the issue that TiKV panics when a full backup fails to find a peer in some extreme cases #16394 @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 an unstable test case #52547 @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 a rare issue that special event timing might cause the data loss in log backup #16739 @YuJuncen

  • TiCDC

    • Fix the issue that TiCDC fails to execute the Exchange Partition ... With Validation DDL downstream after it is written upstream, causing the changefeed to get stuck #10859 @hongyunyan
    • Fix the issue that snapshot lost caused by GC is not reported in time when resuming a changefeed and the checkpoint-ts of the changefeed is smaller than the GC safepoint of TiDB #10463 @sdojjy
    • Fix the issue that TiCDC panics when scheduling table replication tasks #10613 @CharlesCheung96
    • Fix the issue that data is written to a wrong CSV file due to wrong BarrierTS in scenarios where DDL statements are executed frequently #10668 @lidezhu
    • Fix the issue that a changefeed with eventual consistency enabled might fail when the object storage sink encounters a temporary failure #10710 @CharlesCheung96
    • Fix the issue that the old value part of open-protocol incorrectly outputs the default value according to the STRING type instead of its actual type #10803 @3AceShowHand

  • TiDB Lightning

    • Fix the issue that TiDB Lightning panics when importing an empty table of Parquet format #52518 @kennytm
    • Fix the issue that sensitive information in logs is printed in server mode #36374 @kennytm