[PHOENIX-2974] SELECT COUNT(DISTINCT c1, c2,...) throws NPE

• Type: Bug
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Assignee: Unassigned
• Reporter: Lars Hofhansl
• Created: 08/Jun/16 17:57
• Updated: 08/Jun/16 17:57

Description

See discussion on PHOENIX-2965.

Phoenix throws an NPE for a query like this: SELECT COUNT(DISINCT p1, p2) FROM table

java.lang.NullPointerException
	at org.apache.phoenix.parse.FunctionParseNode.validate(FunctionParseNode.java:136)
	at org.apache.phoenix.compile.ExpressionCompiler.visitLeave(ExpressionCompiler.java:325)
	at org.apache.phoenix.compile.ProjectionCompiler$SelectClauseVisitor.visitLeave(ProjectionCompiler.java:680)
	at org.apache.phoenix.compile.ProjectionCompiler$SelectClauseVisitor.visitLeave(ProjectionCompiler.java:576)
	at org.apache.phoenix.parse.FunctionParseNode.accept(FunctionParseNode.java:86)
	at org.apache.phoenix.compile.ProjectionCompiler.compile(ProjectionCompiler.java:408)
	at org.apache.phoenix.compile.QueryCompiler.compileSingleFlatQuery(QueryCompiler.java:564)
	at org.apache.phoenix.compile.QueryCompiler.compileSingleQuery(QueryCompiler.java:510)
	at org.apache.phoenix.compile.QueryCompiler.compileSelect(QueryCompiler.java:205)
	at org.apache.phoenix.compile.QueryCompiler.compile(QueryCompiler.java:157)

While not it's not standard and many DBs do not support this, I think we can discuss supporting this, or at the very least not throw an NPE.

Issue Links

• is related to: PHOENIX-2965 Use DistinctPrefixFilter logic for COUNT(DISTINCT ...) and COUNT(...) GROUP BY