Weekly update in TiDB

Last week, we landed 33 PRs in the TiDB repositories.

Added

• Support priority options in the select statement.
• Add the GetOwnerID interface in OwnerManager.
• Add some columns in mysql.db: Make it compatible with MySQL.
• Add the IsolationLevel option in the coprocessor request to TiKV.
• Add the priority option in Key-Value request to TiKV.
• Support the RenameTable statement without the To keyword.

Fixed

• Fix a bug in the update statement like update T set a = 8, b = a.
• Consider the timezone information when using current_timestamp as the default value.
• Break the campaigning owner loop when closing a DDL worker.
• Check the validity of table name in the CreateTable statement.
• Handle the null argument in substr function.
• Disable concurrent pre-write when meeting the SkipConstrainCheck option.
• Handle binary data in the HEX function and the unhex function.
• Return ErrNoDB (No database selected) when no database is used and the table name is without database qualifier.

Improved

• Refactor optimiser:
  • Prune ordered column paths.
  • Prepare for using the new CBO framework.
• Flatten the row operations.
• Log critical statements.
• Code clean up.

New contributor

sempr JackDrogon Zhang Jian

Weekly update in TiKV

Last week, We landed 12 PRs in the TiKV repositories.

Added

• Use the bi-directional stream for PD region heartbeat.
• Add the selection executor for coprocessor.
• Support the read committed isolation level for transactions.
• Add the modify function for JSON document.

Fixed

• Use Equal to check parsed timestamp.
• Fix the heartbeat tests.

Improved

• Generate snapshot concurrently.
• Skip handling read only commands in the Raft apply worker.
• Upgrade Rust Protobuf to the 1.4 version.