[CALCITE-4623] SemiJoinRule should not match SEMI join

• Type: Task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.26.0
• Fix Version/s: 1.28.0
• Component/s: core
• Labels: pull-request-available
• Assignee: Stamatis Zampetakis
• Reporter: Ruben Q L
• Created: 26/May/21 15:02
• Updated: 20/Oct/21 05:24
• Resolved: 15/Jul/21 08:11

Description

Issue pointed out by zabetak during the review of CALCITE-4621.

Currently, SemiJoinRule (both CoreRules.JOIN_TO_SEMI_JOIN and CoreRules.PROJECT_TO_SEMI_JOIN) matches INNER, LEFT and SEMI join. This last join type seems a bit bizarre (why matching a SEMI join if the purpose of this rule is precisely generating one?).
It seems that SEMI was introduced in the rule by the "big join design refactoring" (see CALCITE-2969 and 4809393).

The purpose of this ticket is to confirm whether or not processing SEMI in SemiJoinRule makes sense (and if not, remove it).

Issue Links

• relates to: CALCITE-4621 SemiJoinRule throws AssertionError on ANTI join
• relates to: CALCITE-2969 Improve design of join-like relational expressions
• links to: GitHub Pull Request #2460