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optimize IN and NOT IN with one or no members

This commit is contained in:
Jan Steemann 2014-09-19 18:22:01 +02:00
parent 767052e0fe
commit 9699091466
1 changed files with 24 additions and 0 deletions
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24
arangod/Aql/Ast.cpp
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@ -1269,6 +1269,30 @@ AstNode* Ast::optimizeBinaryOperatorRelational (AstNode* node) {
bool const lhsIsConst = lhs->isConstant();
bool const rhsIsConst = rhs->isConstant();
if (! lhs->canThrow() &&
rhs->type == NODE_TYPE_LIST &&
rhs->numMembers() <= 1 &&
(node->type == NODE_TYPE_OPERATOR_BINARY_IN ||
node->type == NODE_TYPE_OPERATOR_BINARY_NIN)) {
// turn an IN or a NOT IN with few members into an equality comparison
if (rhs->numMembers() == 0) {
// IN with no members returns false
// NOT IN with no members returns true
return createNodeValueBool(node->type == NODE_TYPE_OPERATOR_BINARY_NIN);
}
else if (rhs->numMembers() == 1) {
// IN with a single member becomes equality
// NOT IN with a single members becomes unequality
if (node->type == NODE_TYPE_OPERATOR_BINARY_IN) {
return createNodeBinaryOperator(NODE_TYPE_OPERATOR_BINARY_EQ, lhs, rhs->getMember(0));
}
return createNodeBinaryOperator(NODE_TYPE_OPERATOR_BINARY_NE, lhs, rhs->getMember(0));
}
// fall-through intentional
}
if (! rhsIsConst) {
return node;