Weekly update in TiDB

Last week, we landed 50 PRs in the TiDB repositories.

Added

• Support ALTER TABLE RENAME KEY
• Support SHOW MASTER STATUS
• Support setting TSO into the tidb_snapshot session variable
• Support the ALTER TABLE DROP COLUMN CASCADE syntax

Fixed

• Make TIDB_SMJ take effect when no index can be used
• Fix the SelectLock option for the UNION statement
• Fix a bug of the DROP USER statement
• Fix a bug of WrapWithCastAsJSON
• Detect the duplication of table alias for the JOIN statement
• Fix some bugs of the DECIMAL values
• Do not allow the YEAR type to have the UNSIGNED flag
• Refine row count estimation
• Fix a bug of failing to fetch the profile by pprof
• Fix the wrong result of the UNION statement
• Fix the wrong result of Merge Join
• Handle NULL datum when converting it to a string in statistics
• Fix the issue of checking LIMIT and ORDER BY in the UNION statement

Improved

• Add max backoff settings for tikv-client
• Support parallel projection
• Make the error message of ADMIN CHECK TABLE more readable
• Improve the constant folding for the IF and IFNULL built-in functions
• Push the FLOOR built-in function to TiKV
• Push the built-in functions IS TRUE/IS FALSE to TiKV
• Append the current time into the error message when backoff occurs
• Refine the result of the EXPLAIN statement

Weekly update in TiSpark

Last week, we landed 2 PRs in the TiSpark repositories.

Fixed

• Fix a test failure

Weekly update in TiKV and PD

Last week, we landed 20 PRs in the TiKV and PD repositories.

Added

• Report the number of rows in the Region

Fixed

• Fix a bug in do_sub

Improved

• Increase metrics of sending and generating a snapshot
• Add ReadExecutor to execute the Get and Snap commands
• Upgrade etcd to master