release-3.0.17.md

title
TiDB 3.0.17 Release Notes

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