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tidb v4.0.0-beta.1 Release Notes

Release Date: 2020-02-28 // about 4 years ago

  • Compatibility Changes

    • Modify the password field name to authentication_string in the mysql.user system table to make it consistent with MySQL 5.7 #14598
    • 🔧 Adjust the default value of the txn-total-size-limit configuration item from 1GB to 100MB #14522
    • 👌 Support dynamically modifying or updating configuration items read from PD #14750 #14303 #14830

    🆕 New Features

    • Support querying slow logs of any time in the SLOW_QUERY / CLUSTER_SLOW_QUERY system table #14840 #14878
    • 👌 Support SQL performance diagnosis
      #14843 #14810 #14835 #14801 #14743
      #14718 #14721 #14670 #14663 #14668
      #14896
    • 👌 Support the Sequence function #14731 #14589 #14674 #14442 #14303 #14830
    • 👌 Support dynamically modifying or updating configuration items read from PD #14750 #14303 #14830
    • ➕ Add a feature of automatically reading data from different roles according to the load balancing policy and add the leader-and-follower system variable to enable this feature #14761
    • ➕ Add the Coercibility function #14739
    • 👌 Support setting TiFlash replicas in the partitioned table #14735 #14713 #14644
    • 👌 Improve the privilege check for the SLOW_QUERY table #14451
    • 👌 Support automatically write the intermediate results to the disk file if the memory is insufficient when using a SQL join #14708 #14279
    • 👌 Support checking table partitions by querying the information_schema.PARTITIONS system table #14347
    • ➕ Add the json_objectagg aggregate function #11154
    • 👌 Support logging rejected connection attempts in the audit log #14594
    • ➕ Add the max-server-connections configuration item (4096 by default) to control the number of connections to a single server #14409
    • 👌 Support the isolation read specifying multiple storage engines at the server level #14440
    • ⚡️ Optimize the cost model of the Apply operator and the Sort operator to improve stability #13550 #14708

    🛠 Bugfix

    • 🛠 Fix the issue that an error is reported when creating view with a column name that exceeds 64 characters #14850
    • 🛠 Fix the issue that duplicate data exists in information_schema.views because the create or replace view statement is incorrectly processed #14832
    • 🛠 Fix the incorrect results of BatchPointGet when plan cache is enabled #14855
    • 🛠 Fix the issue that data is inserted into the wrong partitioned table after the timezone is modified #14370
    • 🛠 Fix the panic occurred when rebuilding expression using the invalid name of the IsTrue function during the outer join simplification #14515
    • 🛠 Fix the the incorrect privilege check for theshow binding statement #14443