You are viewing the documentation of an older version of the TiDB database (TiDB v5.3).

It is recommended that you use the latest LTS version of the TiDB database.

TiDB 2.0 RC1 Release Notes

On March 9, 2018, TiDB 2.0 RC1 is released. This release has great improvement in MySQL compatibility, SQL optimization and stability.


  • Support limiting the memory usage by a single SQL statement, to reduce the risk of OOM
  • Support pushing the Stream Aggregate operator down to TiKV
  • Support validating the configuration file
  • Support obtaining the information of TiDB configuration through HTTP API
  • Compatible with more MySQL syntax in Parser
  • Improve the compatibility with Navicat
  • Improve the optimizer and extract common expressions with multiple OR conditions, to choose better query plan
  • Improve the optimizer and convert subqueries to Join operators in more scenarios, to choose better query plan
  • Resolve Lock in the Batch mode to increase the garbage collection speed
  • Fix the length of Boolean field to improve compatibility
  • Optimize the Add Index operation and give lower priority to all write and read operations, to reduce the impact on online business


  • Optimize the logic of code used to check the Region status to improve performance
  • Optimize the output of log information in abnormal conditions to facilitate debugging
  • Fix the monitor statistics that the disk space of TiKV nodes is not enough
  • Fix the wrong reporting issue of the health interface when TLS is enabled
  • Fix the issue that concurrent addition of replicas might exceed the threshold value of configuration, to improve stability


  • Fix the issue that gRPC call is not cancelled when PD leaders switch
  • Protect important configuration which cannot be changed after initial configuration
  • Add gRPC APIs used to obtain metrics
  • Check whether SSD is used when you start the cluster
  • Optimize the read performance using ReadPool, and improve the performance by 30% in the raw get test
  • Improve metrics and optimize the usage of metrics
Was this page helpful?