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TiDB 2.0 RC5 Release Notes

On April 17, 2018, TiDB 2.0 RC5 is released. This release has great improvement in MySQL compatibility, SQL optimization and stability.


  • Fix the issue about applying the Top-N pushdown rule
  • Fix the estimation of the number of rows for the columns that contain NULL values
  • Fix the zero value of the Binary type
  • Fix the BatchGet issue within a transaction
  • Clean up the written data while rolling back the Add Index operation, to reduce consumed space
  • Optimize the insert on duplicate key update statement to improve the performance by 10 times
  • Fix the issue about the type of the results returned by the UNIX_TIMESTAMP function
  • Fix the issue that the NULL value is inserted while adding NOT NULL columns
  • Support showing memory usage of the executing statements in the Show Process List statement
  • Fix the issue that Alter Table Modify Column reports an error in extreme conditions
  • Support setting the table comment using the Alter statement


  • Add support for Raft Learner
  • Optimize the Balance Region Scheduler to reduce scheduling overhead
  • Adjust the default value of schedule-limit configuration
  • Fix the issue of allocating ID frequently
  • Fix the compatibility issue when adding a new scheduler


  • Support the Region specified by compact in tikv-ctl
  • Support Batch Put, Batch Get, Batch Delete and Batch Scan in the RawKVClient
  • Fix the OOM issue caused by too many snapshots
  • Return more detailed error information in Coprocessor
  • Support dynamically modifying the block-cache-size in TiKV through tikv-ctl
  • Further improve importer
  • Simplify the ImportSST::Upload interface
  • Configure the keepalive property of gRPC
  • Split tikv-importer from TiKV as an independent binary
  • Provide statistics about the number of rows scanned by each scan range in Coprocessor
  • Fix the compilation issue on the macOS system
  • Fix the issue of misusing a RocksDB metric
  • Support the overflow as warning option in Coprocessor
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