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TiDB RC2 Release Notes |
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On August 4, 2017, TiDB RC4 is released! This release is focused on the compatibility with MySQL, SQL query optimizer, system stability and performance in this version. What’s more, a new permission management mechanism is added and users can control data access in the same way as the MySQL privilege management system.
- Query optimizer
- Collect column/index statistics and use them in the query optimizer
- Optimize the correlated subquery
- Optimize the Cost Based Optimizer (CBO) framework
- Eliminate aggregation using unique key information
- Refactor expression evaluation framework
- Convert Distinct to GroupBy
- Support the topn operation push-down
- Support basic privilege management
- Add lots of MySQL built-in functions
- Improve the Alter Table statement and support the modification of table name, default value and comment
- Support the Create Table Like statement
- Support the Show Warnings statement
- Support the Rename Table statement
- Restrict the size of a single transaction to avoid the cluster blocking of large transactions
- Automatically split data in the process of Load Data
- Optimize the performance of the AddIndex and Delete statement
- Support "ANSI_QUOTES" sql_mode
- Improve the monitoring system
- Fix Bugs
- Solve the problem of memory leak
- Support location aware replica scheduling
- Conduct fast scheduling based on the number of region
- pd-ctl support more features
- Add or delete PD
- Obtain Region information with Key
- Add or delete scheduler and operator
- Obtain cluster label information
- Support Async Apply to improve the entire write performance
- Use prefix seek to improve the read performance of Write CF
- Use memory hint prefix to improve the insert performance of Raft CF
- Optimize the single read transaction performance
- Support more push-down expressions
- Improve the monitoring system
- Fix Bugs