[FLINK-14064] Support Project Push down to LookupableTableSource

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Invalid
• Affects Version/s: 1.9.0
• Component/s: Table SQL / Planner
• Assignee: Unassigned
• Reporter: hailong wang
• Created: 12/Sep/19 05:22
• Updated: 16/Dec/19 14:10
• Resolved: 16/Dec/19 14:10

Description

Consider such a temporal join sql:

 

SELECT T.id, D.id, D.name FROM T JOIN temporalTable for system_time AS OF T.proctime AS D ON upper(T.id) = upper(D.id)

When apply a sql function to equivalent condition such as 'upper', it doesn't support. In other words, temporal join don't support any transfrom on temporal  table primary key field.

There are two reasons:

1、In CommonLookupJoin.getIdenticalSourceField method, we can not get the input index when expr is a rexCall except IN_FENNEL and CAST;

2、StreamExecLookupJoinRule doesn't push down project function to LookupableTableSource, so LookupFunction can not perceive the transfrom of primary key.