TiDB 2.0 RC4 Release Notes

On March 30, 2018, TiDB 2.0 RC4 is released. This release has great improvement in MySQL compatibility, SQL optimization and stability.

TiDB

Support SHOW GRANTS FOR CURRENT_USER();
Fix the issue that the Expression in UnionScan is not cloned
Support the SET TRANSACTION syntax
Fix the potential goroutine leak issue in copIterator
Fix the issue that admin check table misjudges the unique index including null
Support displaying floating point numbers using scientific notation
Fix the type inference issue during binary literal computing
Fix the issue in parsing the CREATE VIEW statement
Fix the panic issue when one statement contains both ORDER BY and LIMIT 0
Improve the execution performance of DecodeBytes
Optimize LIMIT 0 to TableDual, to avoid building useless execution plans

Support splitting Region manually to handle the hot spot in a single Region
Fix the issue that the label property is not displayed when pdctl runs config show all
Optimize metrics and code structure

Limit the memory usage during receiving snapshots, to avoid OOM in extreme conditions
Support configuring the behavior of Coprocessor when it encounters warnings
Support importing the data pattern in TiKV
Support splitting Region in the middle
Increase the speed of CI test
Use crossbeam channel
Fix the issue that too many logs are output caused by leader missing when TiKV is isolated