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.

TiDB:

  • 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

PD:

  • 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

TiKV:

  • 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