vvivekiyer commented on code in PR #8518:
URL: https://github.com/apache/pinot/pull/8518#discussion_r863226257
##########
pinot-common/src/main/java/org/apache/pinot/sql/parsers/rewriter/PredicateComparisonRewriter.java:
##########
@@ -33,75 +36,126 @@ public class PredicateComparisonRewriter implements
QueryRewriter {
public PinotQuery rewrite(PinotQuery pinotQuery) {
Expression filterExpression = pinotQuery.getFilterExpression();
if (filterExpression != null) {
-
pinotQuery.setFilterExpression(updateComparisonPredicate(filterExpression));
+ pinotQuery.setFilterExpression(updatePredicate(filterExpression, null));
}
Expression havingExpression = pinotQuery.getHavingExpression();
if (havingExpression != null) {
-
pinotQuery.setHavingExpression(updateComparisonPredicate(havingExpression));
+ pinotQuery.setHavingExpression(updatePredicate(havingExpression, null));
}
return pinotQuery;
}
- // This method converts a predicate expression to the what Pinot could
evaluate.
- // For comparison expression, left operand could be any expression, but
right operand only
- // supports literal.
- // E.g. 'WHERE a > b' will be updated to 'WHERE a - b > 0'
- private static Expression updateComparisonPredicate(Expression expression) {
- Function function = expression.getFunctionCall();
- if (function != null) {
- FilterKind filterKind;
- try {
- filterKind = FilterKind.valueOf(function.getOperator());
- } catch (Exception e) {
- throw new SqlCompilationException("Unsupported filter kind: " +
function.getOperator());
- }
- List<Expression> operands = function.getOperands();
- switch (filterKind) {
- case AND:
- case OR:
- case NOT:
-
operands.replaceAll(PredicateComparisonRewriter::updateComparisonPredicate);
- break;
- case EQUALS:
- case NOT_EQUALS:
- case GREATER_THAN:
- case GREATER_THAN_OR_EQUAL:
- case LESS_THAN:
- case LESS_THAN_OR_EQUAL:
- Expression firstOperand = operands.get(0);
- Expression secondOperand = operands.get(1);
+ /**
+ * This method converts a predicate expression to the what Pinot could
evaluate.
+ * 1. For comparison expression, left operand could be any expression, but
right operand only
+ * supports literal. E.g. 'WHERE a > b' will be converted to 'WHERE a - b
> 0'
+ * 2. Updates boolean predicates (literals and scalar functions) that are
missing an EQUALS filter.
+ * E.g. 1: 'WHERE a' will be updated to 'WHERE a = true'
+ * E.g. 2: "WHERE startsWith(col, 'str')" will be updated to "WHERE
startsWith(col, 'str') = true"
+ *
+ * @param expression current expression in the expression tree
+ * @param parentFunction parentFunction parent expression
+ * @return re-written expression.
+ */
+ private static Expression updatePredicate(Expression expression, Function
parentFunction) {
+ ExpressionType type = expression.getType();
+ if (type == ExpressionType.FUNCTION) {
+ Function function = expression.getFunctionCall();
+ String functionOperator = function.getOperator();
- // Handle predicate like '10 = a' -> 'a = 10'
- if (firstOperand.isSetLiteral()) {
- if (!secondOperand.isSetLiteral()) {
- function.setOperator(getOppositeOperator(filterKind).name());
- operands.set(0, secondOperand);
- operands.set(1, firstOperand);
+ if (!EnumUtils.isValidEnum(FilterKind.class, functionOperator)) {
+ // If the function is not of FilterKind, we might have to rewrite the
function if parentFunction is not a
+ // predicate.
+ // Example: A query like "select col1 from table where
startsWith(col1, 'myStr') AND col2 > 10;" should be
+ // rewritten to "select col1 from table where
startsWith(col1, 'myStr') = true AND col2 > 10;".
+ expression = convertPredicateToBooleanExpression(expression,
parentFunction);
+ return expression;
+ } else {
+ FilterKind filterKind = FilterKind.valueOf(function.getOperator());
+ List<Expression> operands = function.getOperands();
+ switch (filterKind) {
+ case AND:
+ case OR:
+ case NOT:
+ for (int i = 0; i < operands.size(); i++) {
+ Expression operand = operands.get(i);
+ operands.set(i, updatePredicate(operand, function));
}
break;
- }
+ case EQUALS:
+ case NOT_EQUALS:
+ case GREATER_THAN:
+ case GREATER_THAN_OR_EQUAL:
+ case LESS_THAN:
+ case LESS_THAN_OR_EQUAL:
+ Expression firstOperand = operands.get(0);
+ Expression secondOperand = operands.get(1);
- // Handle predicate like 'a > b' -> 'a - b > 0'
- if (!secondOperand.isSetLiteral()) {
- Expression minusExpression =
RequestUtils.getFunctionExpression("minus");
-
minusExpression.getFunctionCall().setOperands(Arrays.asList(firstOperand,
secondOperand));
- operands.set(0, minusExpression);
- operands.set(1, RequestUtils.getLiteralExpression(0));
+ // Handle predicate like '10 = a' -> 'a = 10'
+ if (firstOperand.isSetLiteral()) {
+ if (!secondOperand.isSetLiteral()) {
+ function.setOperator(getOppositeOperator(filterKind).name());
+ operands.set(0, secondOperand);
+ operands.set(1, firstOperand);
+ }
+ break;
+ }
+
+ // Handle predicate like 'a > b' -> 'a - b > 0'
+ if (!secondOperand.isSetLiteral()) {
+ Expression minusExpression =
RequestUtils.getFunctionExpression("minus");
+
minusExpression.getFunctionCall().setOperands(Arrays.asList(firstOperand,
secondOperand));
+ operands.set(0, minusExpression);
+ operands.set(1, RequestUtils.getLiteralExpression(0));
+ break;
+ }
break;
- }
- break;
- default:
- int numOperands = operands.size();
- for (int i = 1; i < numOperands; i++) {
- if (!operands.get(i).isSetLiteral()) {
- throw new SqlCompilationException(
- String.format("For %s predicate, the operands except for the
first one must be literal, got: %s",
- filterKind, expression));
+ default:
+ int numOperands = operands.size();
+ for (int i = 1; i < numOperands; i++) {
+ if (!operands.get(i).isSetLiteral()) {
+ throw new SqlCompilationException(String
+ .format("For %s predicate, the operands except for the
first one must be literal, got: %s",
+ filterKind, expression));
+ }
}
- }
- break;
+ break;
+ }
}
+ } else if (type == ExpressionType.IDENTIFIER) {
+ expression = convertPredicateToBooleanExpression(expression,
parentFunction);
}
+
+ return expression;
+ }
+
+ /**
+ * Rewrite if one of the two conditions are satisfied:
+ * 1. parent function is empty.
+ * Example1: "select * from table where col1" converts to
+ * "select * from table where col1 = true"
+ * Example2: "select * from table where startsWith(col1, 'str')"
converts to
+ * "select * from table where startsWith(col1, 'str') = true"
+ * 2. Separator is not a predicate (non predicates are AND, OR, NOT).
+ * Example1: "select * from table where col1 AND startsWith(col2,
'str')" converts to
+ * "select * from table where col1 = true AND startsWith(col2,
'str') = true"
+ * @param expression Expression
+ * @param parentFunction Parent expression
+ * @return Rewritten expression
+ */
+ private static Expression convertPredicateToBooleanExpression(Expression
expression, Function parentFunction) {
+ if (parentFunction == null || (EnumUtils.isValidEnum(FilterKind.class,
parentFunction.getOperator()) && !FilterKind
Review Comment:
I see your point now. The code is much cleaner following this suggestion.
Thanks!
##########
pinot-common/src/main/java/org/apache/pinot/sql/parsers/rewriter/PredicateComparisonRewriter.java:
##########
@@ -33,75 +36,126 @@ public class PredicateComparisonRewriter implements
QueryRewriter {
public PinotQuery rewrite(PinotQuery pinotQuery) {
Expression filterExpression = pinotQuery.getFilterExpression();
if (filterExpression != null) {
-
pinotQuery.setFilterExpression(updateComparisonPredicate(filterExpression));
+ pinotQuery.setFilterExpression(updatePredicate(filterExpression, null));
}
Expression havingExpression = pinotQuery.getHavingExpression();
if (havingExpression != null) {
-
pinotQuery.setHavingExpression(updateComparisonPredicate(havingExpression));
+ pinotQuery.setHavingExpression(updatePredicate(havingExpression, null));
}
return pinotQuery;
}
- // This method converts a predicate expression to the what Pinot could
evaluate.
- // For comparison expression, left operand could be any expression, but
right operand only
- // supports literal.
- // E.g. 'WHERE a > b' will be updated to 'WHERE a - b > 0'
- private static Expression updateComparisonPredicate(Expression expression) {
- Function function = expression.getFunctionCall();
- if (function != null) {
- FilterKind filterKind;
- try {
- filterKind = FilterKind.valueOf(function.getOperator());
- } catch (Exception e) {
- throw new SqlCompilationException("Unsupported filter kind: " +
function.getOperator());
- }
- List<Expression> operands = function.getOperands();
- switch (filterKind) {
- case AND:
- case OR:
- case NOT:
-
operands.replaceAll(PredicateComparisonRewriter::updateComparisonPredicate);
- break;
- case EQUALS:
- case NOT_EQUALS:
- case GREATER_THAN:
- case GREATER_THAN_OR_EQUAL:
- case LESS_THAN:
- case LESS_THAN_OR_EQUAL:
- Expression firstOperand = operands.get(0);
- Expression secondOperand = operands.get(1);
+ /**
+ * This method converts a predicate expression to the what Pinot could
evaluate.
+ * 1. For comparison expression, left operand could be any expression, but
right operand only
+ * supports literal. E.g. 'WHERE a > b' will be converted to 'WHERE a - b
> 0'
+ * 2. Updates boolean predicates (literals and scalar functions) that are
missing an EQUALS filter.
+ * E.g. 1: 'WHERE a' will be updated to 'WHERE a = true'
+ * E.g. 2: "WHERE startsWith(col, 'str')" will be updated to "WHERE
startsWith(col, 'str') = true"
+ *
+ * @param expression current expression in the expression tree
+ * @param parentFunction parentFunction parent expression
+ * @return re-written expression.
+ */
+ private static Expression updatePredicate(Expression expression, Function
parentFunction) {
Review Comment:
Done.
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