TiDB RC4 Release Notes
On August 4, 2017, TiDB RC4 is released! This release is focused on MySQL compatibility, SQL optimization, stability, and performance.
- For performance, the write performance is improved significantly, and the computing task scheduling supports prioritizing to avoid the impact of OLAP on OLTP.
- The optimizer is revised for a more accurate query cost estimating and for an automatic choice of the
Join physical operator based on the cost.
- Many enhancements have been introduced to be more compatible with MySQL.
- TiSpark is now released to better support the OLAP business scenarios. You can now use Spark to access the data in TiKV.
- The SQL query optimizer refactoring:
- Better support for TopN queries
- Support the automatic choice of the of the
Join physical operator based on the cost
- Improved Projection Elimination
- The version check of schema is based on Table to avoid the impact of DDL on the ongoing transactions
- Improve the
- Improve the
Index Scan performance
- Many enhancements have been introduced to be more compatible with MySQL
- Support the JSON type and operations
- Support the configuration of query prioritizing and isolation level
Placement Driver (PD)
- Support using PD to set the TiKV location labels
- Optimize the scheduler
- PD is now supported to initialize the scheduling commands to TiKV.
- Accelerate the response speed of the region heartbeat.
- Optimize the
- Optimize data loading to speed up failover
- Support the configuration of query prioritizing
- Support the RC isolation level
- Improve Jepsen test results and the stability
- Support Document Store
- Coprocessor now supports more pushdown functions
- Improve the performance and stability
TiSpark Beta Release
- Implement the prediction pushdown
- Implement the aggregation pushdown
- Implement range pruning
- Capable of running full set of TPC-H except one query that needs view support