2016-10-17-tidb-weekly.md

title	date	summary	tags
Weekly update (October 01 ~ October 16, 2016)	2016-10-17	Last week, we landed 27 PRs in the TiDB repositories and 32 PRs in the TiKV repositories.	TiDB TiKV Placement Driver

Weekly update (October 01 ~ October 16, 2016)

Last week, we landed 27 PRs in the TiDB repositories and 32 PRs in the TiKV repositories.

Notable changes to TiDB

• Support projection elimination so that the executor can run faster when it is not necessary to have a projection layer.

• Write DDL binlog to file.

• Convert sort and limit to top-n in the query planning phrase.

• Support reading history data even if the schema changes.

• Add comments for the server package and the plan package.

• Add metrics for GC configuration.

• Verify the data for utf-8 columns.

• Fix bugs.

Notable changes to TiKV

• Compact the lock column family periodically.
• Add random latency filter to simulate the transport test.
• Improve the datum test coverage.
• Cache the Raft log term to avoid calling rocksdb::get every time.
• Check the store ID before sending to raftstore and refresh expired store address for the resolve process to fix issue 1153.
• Add new regions' meta in StaleEpoch error to fix issue 974.
• Coprocessor supports timezone for timestamp comparison.

Notable changes to Placement Driver

• Ignore balancing the peer with on-going operation to fix TiKV issue 1084.