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pingcap / tidb

TiDB is an open-source, cloud-native, distributed, MySQL-Compatible database for elastic scale and real-time analytics. Try AI-powered Chat2Query free at : https://www.pingcap.com/tidb-serverless/
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GroupJoin #7469

Open zz-jason opened 5 years ago

zz-jason commented 5 years ago

Description

There’s a case that we aggregate the data of a join and the join key is the same with the aggregation’s group-by item. If we chose hash join and hash aggregate, we’ll build a hash table twice. If we can merge them into one operator significantly speeds up query execution. This is discussed in http://www.vldb.org/pvldb/vol4/p843-moerkotte.pdf. Implement it and see its performance on TPC-H benchmark!

Difficulty

sre-bot commented 4 years ago

@qxhy123 don't have enough score, pick up failed Progress 0/400 You may pick up some easy issues first.

sre-bot commented 4 years ago

@qxhy123 don't have enough score, pick up failed Progress 0/400 You may pick up some easy and medium level issues first.