Weekly update (September 26 ~ September 30, 2016)

Last week, we landed 17 PRs in the TiDB repositories and 13 PRs in the TiKV repositories.

Notable changes to TiDB

• Make the GC alive time configurable so that users can keep the deleted data as long as they want.
• Add the metrics for all kinds of statements to provide more information for insights.
• Improve the kv package test coverage.
• Record the processed row count during DDL so that users can track the progress of DDL.
• Consider the limit clause in the cost based optimizer (CBO) framework.
• Add metrics for kv errors.
• Make truncate statement a DDL to convert the truncate operation into a drop table process followed by a create table process. Then TiDB can delete the truncated data with a background worker.

Notable changes to TiKV

• Add a metric for Raft vote to monitor server's stability.
• Improve the test coverage for scheduler, Raft.
• Check the stale snapshot to fix 1084.
• Reuse iterator to speed up scan.
• Remove delete_file_in_range to fix 1121.

Notable changes to Placement Driver (PD)

• Add more metrics to monitor the server.