[CALCITE-2645] SESSION_END() is transformed to RexInputRef, which is always equal to SESSION_START()

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Assignee: Unassigned
• Reporter: Rui Wang
• Created: 29/Oct/18 03:54
• Updated: 04/Nov/19 17:44

Description

https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/sql2rel/AuxiliaryConverter.java#L56

In the AuxiliaryConverter implementation, SESSION_END() is transformed to a RexInputRef, as the same as SESSION_START(). By doing so, it cannot restored when generating physical plan because it cannot be differentiated which RexInputRef is session start, and which RexInputRef is session end.

Ideally, during toRel, SESSION_END can be kept as a RexCall with function information in it. So in the following step, the RexCall can be replaced as a correct input reference to GROUP BY's field.

Issue Links

• blocks: BEAM-5843 Expand Grouped Window Functions to window_start and window_end in Aggregation
• is duplicated by: CALCITE-3472 SESSION_END returns same value as SESSION_START