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https://issues.apache.org/jira/browse/PHOENIX-1030?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14134758#comment-14134758
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James Taylor commented on PHOENIX-1030:
---------------------------------------
Thanks for the patch, [~tdsilva]. Here's some feedback:
- Instead of DeterministicEnum and getDeterministicEnum(), how about
Determinism and getDeterminism()?
- You'll need to add a method on Determinism that combines it with another
Determinism:
{code}
public Determinism combine(Determinism that) {
// Always take the biggest Determinism when combining
return Determinism.values()[Math.max(this.ordinal(), that.ordinal())];
}
{code}
- In the code that was and-ing together isDeterministic(), consistently call
the combine method. I noticed you were doing this sometimes inline, but
sometimes not. This is essentially what propagates the determinism up the
expression tree. For example, for the expression CURRENT_DATE() - 1 the
SubtractExpression would become PER_STATEMENT based on propagating up the
determinism for CURRENT_DATE(). Here's an example of the code I'm referring to:
{code}
@@ -1009,10 +1005,8 @@ public class ExpressionCompiler extends
UnsupportedAllParseNodeVisitor<Expressio
@Override
public Expression create(ArithmeticParseNode node,
List<Expression> children) throws SQLException {
PDataType theType = null;
- boolean isDeterministic = true;
for(int i = 0; i < children.size(); i++) {
Expression e = children.get(i);
- isDeterministic &= e.isDeterministic();
PDataType type = e.getDataType();
if (type == null) {
continue;
@@ -1038,7 +1032,7 @@ public class ExpressionCompiler extends
UnsupportedAllParseNodeVisitor<Expressio
case DOUBLE:
return new DoubleDivideExpression(children);
default:
- return LiteralExpression.newConstant(null, theType,
isDeterministic);
+ return LiteralExpression.newConstant(null, null,
DeterministicEnum.ALWAYS);
}
}
});
{code}
> Change Expression.isDeterministic() to return an ENUM with three values
> {DETERMINISTIC, UNDETERMINISTIC_ROW, UNDETERMINISTIC_STMT}
> ----------------------------------------------------------------------------------------------------------------------------------
>
> Key: PHOENIX-1030
> URL: https://issues.apache.org/jira/browse/PHOENIX-1030
> Project: Phoenix
> Issue Type: Improvement
> Reporter: Thomas D'Silva
> Assignee: Thomas D'Silva
> Attachments: PHOENIX-1030-3.0.patch, PHOENIX-1030-master.patch
>
>
> Change Expression.isDeterministic() to return an ENUM with three values
> DETERMINISTIC - the expression returns the same output every time given the
> same input.
> UNDETERMINISTIC_ROW - the expression should be computed for every row
> UNDETERMINISTIC_STMT - the expression should be be computed for a given
> statement only once
> See PHOENIX-1001
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