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TiDB 2.0 RC3 Release Notes
/docs/dev/releases/release-2.0-rc.3/
/docs/dev/releases/2rc3/
TiDB 2.0 RC3, released on March 23, 2018, brings improvements in MySQL compatibility, SQL optimization, and stability. It includes fixes for various issues, optimizations for execution speed, memory control, and DDL job management. PD now supports Region Merge and has optimizations for leader balance and abnormal Regions. TiKV also supports Region Merge, Raft snapshot process, and streaming in Coprocessor, with various improvements in space management and data recovery.

TiDB 2.0 RC3 Release Notes

On March 23, 2018, TiDB 2.0 RC3 is released. This release has great improvement in MySQL compatibility, SQL optimization and stability.

TiDB

  • Fix the wrong result issue of MAX/MIN in some scenarios
  • Fix the issue that the result of Sort Merge Join does not show in order of Join Key in some scenarios
  • Fix the error of comparison between uint and int in boundary conditions
  • Optimize checks on length and precision of the floating point type, to improve compatibility with MySQL
  • Improve the parsing error log of time type and add more error information
  • Improve memory control and add statistics about IndexLookupExecutor memory
  • Optimize the execution speed of ADD INDEX to greatly increase the speed in some scenarios
  • Use the Stream Aggregation operator when the GROUP BY substatement is empty, to increase the speed
  • Support closing the Join Reorder optimization in the optimizer using STRAIGHT_JOIN
  • Output more detailed status information of DDL jobs in ADMIN SHOW DDL JOBS
  • Support querying the original statements of currently running DDL jobs using ADMIN SHOW DDL JOB QUERIES
  • Support recovering the index data using ADMIN RECOVER INDEX for disaster recovery
  • Attach a lower priority to the ADD INDEX operation to reduce the impact on online business
  • Support aggregation functions with JSON type parameters, such as SUM/AVG
  • Support modifying the lower_case_table_names system variable in the configuration file, to support the OGG data replication tool
  • Improve compatibility with the Navicat management tool
  • Support using implicit RowID in CRUD operations

PD

  • Support Region Merge, to merge empty Regions or small Regions after deleting data
  • Ignore the nodes that have a lot of pending peers during adding replicas, to improve the speed of restoring replicas or making nodes offline
  • Fix the frequent scheduling issue caused by a large number of empty Regions
  • Optimize the scheduling speed of leader balance in scenarios of unbalanced resources within different labels
  • Add more statistics about abnormal Regions

TiKV

  • Support Region Merge
  • Inform PD immediately once the Raft snapshot process is completed, to speed up balancing
  • Add the Raw DeleteRange API
  • Add the GetMetric API
  • Reduce the I/O fluctuation caused by RocksDB sync files
  • Optimize the space reclaiming mechanism after deleting data
  • Improve the data recovery tool tikv-ctl
  • Fix the issue that it is slow to make nodes down caused by snapshot
  • Support streaming in Coprocessor
  • Support Readpool and increase the raw_get/get/batch_get by 30%
  • Support configuring the request timeout of Coprocessor
  • Support streaming aggregation in Coprocessor
  • Carry time information in Region heartbeats
  • Limit the space usage of snapshot files to avoid consuming too much disk space
  • Record and report the Regions that cannot elect a leader for a long time
  • Speed up garbage cleaning when starting the server
  • Update the size information about the corresponding Region according to compaction events
  • Limit the size of scan lock to avoid request timeout
  • Use DeleteRange to speed up Region deletion
  • Support modifying RocksDB parameters online