From 60b4fa0c1cfacc9ad484c08fbbd0de7b69ea27ca Mon Sep 17 00:00:00 2001
From: Jesse Morgan <jesse@jesterpm.net>
Date: Fri, 18 May 2012 21:10:12 +0000
Subject: Adjusted optimization of open ended range queries.

---
 .../com/amazon/carbonado/qe/FilteringScore.java    | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

(limited to 'src/main/java/com/amazon/carbonado')

diff --git a/src/main/java/com/amazon/carbonado/qe/FilteringScore.java b/src/main/java/com/amazon/carbonado/qe/FilteringScore.java
index 5b76a6d..57c16a1 100644
--- a/src/main/java/com/amazon/carbonado/qe/FilteringScore.java
+++ b/src/main/java/com/amazon/carbonado/qe/FilteringScore.java
@@ -823,10 +823,21 @@ public class FilteringScore<S extends Storable> {
                 return 1;
             }
 
-            // Compare range match. (index can have at most one range match)
-            if (first.hasRangeMatch()) {
-                if (second.hasRangeMatch()) {
-                    // Both have range match, favor clustered index.
+            // Compare ranges. Favor ranges that help find the start. 
+            boolean firstPartialRange = first.hasRangeStart();
+            boolean secondPartialRange = second.hasRangeStart();
+            
+            if (first.shouldReverseRange()) {
+                firstPartialRange = first.hasRangeEnd();
+            }
+
+            if (second.shouldReverseRange()) {
+                secondPartialRange = second.hasRangeEnd();
+            }
+
+            if (firstPartialRange) {
+                if (secondPartialRange) {
+                    // Both have ranges, favor clustered index.
                     if (first.isIndexClustered()) {
                         if (!second.isIndexClustered()) {
                             return -1;
@@ -837,7 +848,8 @@ public class FilteringScore<S extends Storable> {
                 } else {
                     return -1;
                 }
-            } else if (second.hasRangeMatch()) {
+
+            } else if (secondPartialRange) {
                 return 1;
             }
 
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