2017-12-11-tidb-weekly.md

title	date	summary	tags
Weekly update (December 04 ~ December 10, 2017)	2017-12-11	Last week, we landed 45 PRs in the TiDB repositories, 12 PRs in the TiSpark repositories, and 21 PRs in the TiKV and PD repositories.	TiDB TiKV PD TiSpark

Weekly update in TiDB

Last week, we landed 45 PRs in the TiDB repositories.

Added

• Add hints to force to choose HashJoin.
• Provide the HTTP API of table disk usage for tidb-ctl.

Fixed

• Fix a bug when updating the JSON field.
• Delete the auto ID key when renaming the table.
• Fix a bug in JoinResultGenerator.
• Fix a bug when backfilling the index with nil.
• The value of a session variable should not be modified when getting a global variable.

Improved

• Move the Cancel function from session to clientConn.
• Reduce a comparison in the union scan.
• Move the binary-tree library from petar/GoLLRB to google/btree.
• Add the Format interface on ExprNode to convert AST back to string.
• Improve the performance of ShowVariables.
• Add Chunk/List to hold a slice of Chunk.
• Add the explain info for TopN.
• Support coprocessor streaming API for the TiKV client.
• Support sql_mode IGNORE SPACE.
• Support the builtin aggregation function bit_xor.
• Refactor SQL query optimizer:
  • Replace Sort with LogicalSort and PhysicalSort.
  • Add Physical operator for Lock, Limit and UnionAll.
  • Make Show no longer a logical/physical plan.
  • Add Physical plan for MaxOneRow, Dual and Exists.
  • Add Physical plan for Projection and TopN.
  • Extract getChildrenPossibleProp to a file.
  • Add PhysicalStreamAgg and remove AggType.
• Support Chunk in executors:
  • InsertExec
  • MaxOneRowExec
  • TopN
  • UnionExec

Weekly update in TiSpark

Last week, we landed 12 PRs in the TiSpark repositories.

Added

• Implement the Coprocessor DAG mode reading.
• Implement TopN pushdown.
• Add the switch for disabling a specific expression pushdown for old versions of TiKV.
• Add the Cache invalidation notification for the client.

Fixed

• Fix the reading error when all values in group aggregate to null.
• Fix a potential error escape from Handler.
• Fix inconsistent PD cache eviction and add capture for leaked exception.
• Fix the pushdown type problem of timestamp.

Weekly update in TiKV and PD

Last week, we landed 21 PRs in the TiKV and PD repositories.

Added

• Add TiltCase and Main.
• Support lower_bound for iterator.
• Add on_tick for BatchRunnable.
• Support getting the unique index.
• Add role_observer in the coprocessor.
• Record the wait time of APPLY_TASK.
• Support disabling the block cache for test.
• Support setting bytes_per_sync and wal_bytes_per_sync.

Fixed

• Use the same configuration for tikv-ctl and tikv-server.
• Fix zero truncation in decimal decoding.
• Call the post_apply hook.
• Support the TLS connection in pd-recover.

Improved

• Improve scheduler metrics.
• Avoid cloning prs in Raft.
• Update Limiter using all pending operators.
• Use a bit field to present the operator kind.
• Update RocksDB with optimized ingesting SST.
• Reduce the log in the MVCC layer.
• Refactor tests for the RPC client.
• Optimize the dev build and fix typo.

New contributors (Thanks!)

• TiDB:
  • Evgeniy Kulikov
  • denofiend
• docs-cn:
  • Guangkuo Bian