TiDB RC3 Release Notes

On June 16, 2017, TiDB RC3 is released! This release is focused on MySQL compatibility, SQL optimization, stability, and performance.

Highlight

The privilege management is refined to enable users to manage the data access privileges using the same way as in MySQL.
DDL is accelerated.
The load balancing policy and process are optimized for performance.
TiDB Ansible is open sourced. By using TiDB-Ansible, you can deploy, upgrade, start and shutdown a TiDB cluster with one click.

The following features are added or improved in the SQL query optimizer:
- Support incremental statistics
- Support the Merge Sort Join operator
- Support the Index Lookup Join operator
- Support the Optimizer Hint Syntax
- Optimize the memory consumption of the Scan, Join, Aggregation operators
- Optimize the Cost Based Optimizer (CBO) framework
- Refactor Expression
Support more complete privilege management
DDL acceleration
Support using HTTP API to get the data distribution information of tables
Support using system variables to control the query concurrency
Add more MySQL built-in functions
Support using system variables to automatically split a big transaction into smaller ones to commit

Support gRPC
Provide the Disaster Recovery Toolkit
Use Garbage Collection to clear stale data automatically
Support more efficient data balance
Support hot Region scheduling to enable load balancing and speed up the data importing
Performance
- Accelerate getting Client TSO
- Improve the efficiency of Region Heartbeat processing
Improve the pd-ctl function
- Update the Replica configuration dynamically
- Get the Timestamp Oracle (TSO)
- Use ID to get the Region information

Support gRPC
Support the Sorted String Table (SST) format snapshot to improve the load balancing speed of a cluster
Support using the Heap Profile to uncover memory leaks
Support Streaming SIMD Extensions (SSE) and speed up the CRC32 calculation
Accelerate transferring leader for faster load balancing
Use Batch Apply to reduce CPU usage and improve the write performance
Support parallel Prewrite to improve the transaction write speed
Optimize the scheduling of the coprocessor thread pool to reduce the impact of big queries on point get
The new Loader supports data importing at the table level, as well as splitting a big table into smaller logical blocks to import concurrently to improve the data importing speed.