[ASTERIXDB-3261][COMP] Limit Costing
Change-Id: I0a3e1be5e134c839168b584a6f41c45682e078ee
Reviewed-on: https://asterix-gerrit.ics.uci.edu/c/asterixdb/+/17808
Integration-Tests: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Tested-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Reviewed-by: Vijay Sarathy <vijay.sarathy@couchbase.com>
diff --git a/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/cbo/JoinEnum.java b/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/cbo/JoinEnum.java
index 752064a..9147184 100644
--- a/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/cbo/JoinEnum.java
+++ b/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/cbo/JoinEnum.java
@@ -889,19 +889,23 @@
private int findLimitValue(AbstractLogicalOperator oper) {
ILogicalOperator op = oper;
+ int limit = -1;
while (op.getOperatorTag() != LogicalOperatorTag.EMPTYTUPLESOURCE) {
if (op.getOperatorTag() == LogicalOperatorTag.LIMIT) {
LimitOperator lop = (LimitOperator) op;
ILogicalExpression expr = lop.getMaxObjects().getValue();
if (expr != null) {
if (expr.getExpressionTag() == LogicalExpressionTag.CONSTANT) { // must be a constant
- return Integer.parseInt(lop.getMaxObjects().getValue().toString());
+ limit = Integer.parseInt(lop.getMaxObjects().getValue().toString());
}
}
}
+ if (op.getOperatorTag() == LogicalOperatorTag.ORDER) {
+ return -1; // This is because we cant reduce the selectivity of a scan operator when an order by is present.
+ }
op = op.getInputs().get(0).getValue();
}
- return -1;
+ return limit;
}
private boolean isPredicateCardinalityAnnotationPresent(ILogicalExpression leExpr) {