tidb v4.0.0-rc Release Notes

Release Date: 2020-04-08 // almost 4 years ago
  • Compatibility Changes

    • ๐ŸŒฒ Refuse to get started instead of returning an alert log when the tidb-server status port is occupied #15177

    ๐Ÿ› Bug Fixes

    • ๐Ÿ›  Fix the issue that replication between the upstream and downstream might go wrong when the DDL job is executed using the PREPARE statement because of the incorrect job query in the internal records #15435
    • ๐Ÿ›  Fix the issue of incorrect subquery result in the Read Commited isolation level #15471
    • ๐Ÿ›  Fix the issue of possible wrong behavior when using INSERT ... VALUES to specify the BIT(N) data type #15350
    • ๐Ÿ›  Fix the issue that the DDL Job internal retry does not fully achieve the expected outcomes because the values of ErrorCount fail to be summed correctly #15373
    • ๐Ÿ›  Fix the issue that Garbage Collection might work abnormally when TiDB connects to TiFlash #15505
    • ๐Ÿ›  Fix the issue of incorrect result caused by the Inline Projection optimization #15411
    • ๐Ÿ”€ Fix the issue that the SQL Hint INL_MERGE_JOIN is executed incorrectly in some cases #15515
    • ๐Ÿ›  Fix the issue that columns with the AutoRandom attribute are rebased when the negative number is explicitly written to these columns #15397

    ๐Ÿ†• New Features and Improvements

    • Add the case-sensitive collation so that users can enable utf8mb4_general_ci and utf8_general_ci in a new cluster #33
    • โœจ Enhance the RECOVER TABLE syntax to support recovering truncated tables #15398
    • ๐ŸŒฒ Refuse to get started instead of returning an alert log when the the tidb-server status port is occupied #15177
    • ๐ŸŽ Optimize the write performance of using a sequence as the default column values #15216
    • โž• Add the DDLJobs system table to query the details of DDL jobs #14837
    • ๐ŸŽ Optimize the aggFuncSum performance #14887
    • โšก๏ธ Optimize the output of EXPLAIN #15507