[BEAM-3345] [SQL] Reject Unsupported Joins

• Type: Task
• Status: Resolved
• Priority: P2
• Resolution: Fixed
• Fix Version/s: Not applicable
• Component/s: dsl-sql
• Assignee: Anton Kedin
• Reporter: Anton Kedin
• Created: 13/Dec/17 22:36
• Updated: 24/Jul/20 20:15
• Resolved: 02/Mar/18 01:34

Description

Related to https://issues.apache.org/jira/browse/BEAM-3190 .

We don't know what meaningful join semantics is, in presence of multiple trigger firings. I.e. in accumulating mode it will result in multiple duplicated join results, and in discarding mode it will only join deltas, both of these scenarios seem to be super subtle and can lead to misunderstanding and misuse by the end users.

Until we have a way to implement a correct join semantics (e.g. using retractions) we should reject unsupported window/trigger combinations.

Issue Links

• is blocked by: BEAM-3360 [SQL] Do not assign triggers for HOP/TUMBLE
• is related to: BEAM-3190 [SQL] Join Windowing Semantics
• links to: GitHub Pull Request #4642