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TiDB 3.0.17 Release Notes

Release date: Aug 3, 2020

TiDB version: 3.0.17

Improvements

  • TiDB

    • Decrease the default value of the query-feedback-limit configuration item from 1024 to 512, and improve the statistics feedback mechanism to ease its impact on the cluster #18770
    • Limit batch split count for one request #18694
    • Accelerate /tiflash/replica HTTP API when there are many history DDL jobs in the TiDB cluster #18386
    • Improve row count estimation for index equal condition #17609
    • Speed up the execution of kill tidb conn_id #18506
  • TiKV

    • Add the hibernate-timeout configuration that delays region hibernation to improve rolling update performance #8207
  • Tools

    • TiDB Lightning

      • [black-white-list] has been deprecated with a newer, easier-to-understand filter format #332

Bug Fixes

  • TiDB

    • Return the actual error message instead of an empty set when a query which contains IndexHashJoin or IndexMergeJoin encounters a panic #18498
    • Fix the unknown column error for SQL statements like SELECT a FROM t HAVING t.a #18432
    • Forbid adding a primary key for a table when the table has no primary key or when the table already has an integer primary key #18342
    • Return an empty set when executing EXPLAIN FORMAT="dot" FOR CONNECTION #17157
    • Fix STR_TO_DATE's handling for format token '%r', '%h' #18725
  • TiKV

    • Fix a bug that might read stale data during region merging #8111
    • Fix the issue of memory leak during the scheduling process #8355
  • Tools

    • TiDB Lightning

      • Fix the issue that the log-file flag is ignored #345