[CALCITE-2226] Druid adapter: Substring operator converter does not handle non-constant literals correctly

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.16.0
• Fix Version/s: 1.17.0
• Component/s: druid
• Assignee: slim bouguerra
• Reporter: slim bouguerra
• Created: 28/Mar/18 17:09
• Updated: 20/Jul/18 08:18
• Resolved: 03/Apr/18 01:57

Description

Query like the following

SELECT substring(namespace, CAST(deleted AS INT), 4)
FROM druid_table;

will fail with

java.lang.AssertionError: not a literal: $13
	at org.apache.calcite.rex.RexLiteral.findValue(RexLiteral.java:963)
	at org.apache.calcite.rex.RexLiteral.findValue(RexLiteral.java:955)
	at org.apache.calcite.rex.RexLiteral.intValue(RexLiteral.java:938)
	at org.apache.calcite.adapter.druid.SubstringOperatorConversion.toDruidExpression(SubstringOperatorConversion.java:46)
	at org.apache.calcite.adapter.druid.DruidExpressions.toDruidExpression(DruidExpressions.java:120)
	at org.apache.calcite.adapter.druid.DruidQuery.computeProjectAsScan(DruidQuery.java:746)
	at org.apache.calcite.adapter.druid.DruidRules$DruidProjectRule.onMatch(DruidRules.java:308)
	at org.apache.calcite.plan.AbstractRelOptPlanner.fireRule(AbstractRelOptPlanner.java:317)

Druid Substring converter is assuming that index is always a constant literal, which is wrong.

Issue Links

• relates to: HIVE-18996 SubString Druid convertor assuming that index is always constant literal value
• links to: Pull Request