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support join elimination rule #7704

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zz-jason opened this issue Sep 14, 2018 · 0 comments

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zz-jason commented Sep 14, 2018

Feature Request

Describe the feature you'd like:

Three kinds of join eliminations:

~~inner join elimination~~. Since it's based on the foreign key constraint, no need to consider it in TiDB
outer join elimination. For example left outer join, if the parent only use the columns from left table and the join key of right table(the inner table) is a unique key of the right table. the left outer join can be eliminated.
outer join elimination with distinct. see the examples in the reference for more detail.

reference:
https://blog.jooq.org/2017/09/01/join-elimination-an-essential-optimiser-feature-for-advanced-sql-usage/

zz-jason added type/enhancement sig/planner labels

zz-jason added this to the 2.1 milestone

zz-jason self-assigned this

lzmhhh123 assigned lzmhhh123 and unassigned zz-jason

lzmhhh123 mentioned this issue

planner: support join elimination rule #8021

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lzmhhh123 closed this as completed

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