2017-08-28-tidb-weekly.md

title	date	summary	tags
Weekly update (August 21 ~ August 27, 2017)	2017-08-28	Last week, we landed 55 PRs in the TiDB repositories and 21 PRs in the TiKV repositories.	TiDB TiKV

Weekly update in TiDB

Last week, we landed 55 PRs in the TiDB repositories.

Added

• Support the 'SHOW PLUGINS' syntax with dummy implementation.
• Add a system variable to split to-be-deleted data into batches autmatically.
• Add the date literal.
• Add the framework of the X protocol, and commond line arguments.

Fixed

• Fix a panic when the set statement meets a subquery.
• Set charset and collation for the union's result.
• Fix show column comment, show create table auto-increment.
• Fix the bug in Date comparison.
• Fix the bug in index selection.
• Rewrite the index join plan generation to correct wrong index selection.
• Avoid 'binary BINARY' for a special field type.
• Correct overflow check on the MINUS function.
• Fix a bug when casting JSON to other types.
• Concatenates string literals which placed each other.
• Fix an issue that the flags of the 'IFNULL' Builtin function result is not consistent with MySQL.

Improved

• Enlarge the batch size from 128M to 256M to reduce the network round-trip.
• Suport coalesce pushdown.
• Make auto analyze more conservative.
• Support isnull pushdown.
• Implement the MVCCStore interface using the leveldb backend.
• Calculate generated columns in CRUD.
• Refactor the following expression/builtin-function evaluation framework:
  • TIMESTAMP
  • DAYNAME
  • DATE
  • UTC_TIME
  • MONTHNAME
  • WEEKDAY, FROM_DAYS, QURTER
  • LAST_DAY
  • DAYOFWEEK, DAYOFMONTH, DAYOFYEAR
  • FIND_IN_SET
  • DATEDIFF
  • CURDATE, SYSDATE, YEARWEEK
  • YEAR, MONTH
  • WEEK, WEEKOFYEAR
  • NOW, UTC_TIMESTAMP, UTC_DATE
  • TIMESTAMPDIFF
  • COALESCE

New Contributor (Thanks!)

• David Ding
• xiaojian Cai
• bailaohe

Weekly update in TiKV

Last week, We landed 21 PRs in the TiKV repositories.

Added

• Use dedicated Rocksdb instance to store Raft log.
• Add builtin_cast-II for DAG/expression.
• Add builtin scalar function operator for DAG.
• Add arithmetic operations for DAG.
• Add builtin conditions for DAG.
• Add more RocksDB metrics.
• Support negative operator for decimal.

Fixed

• Fix a data race for PD.
• Fix a heartbeat stream bug for PD.
• Fix a bug with reverse scan.

Improved

• Refactor the Coprocessor thread pool to pass contexts.
• Improve tests.
• Add timeout for RPC calls.
• Remove timeout for streaming calls.
• Make max tasks configurable for the Coprocessor.
• Move the heartbeat approximate size to PD worker.