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.