MONDRIAN - enhance nativizeSet so that it can utilize the approxRowCo…

…unt on a level instead of querying for cardinality every time. [git-p4: depot-paths = "//open/mondrian/": change = 13215]
pentaho · Dec 8, 2009 · 8e97f79 · 8e97f79
1 parent 6808269
commit 8e97f79
Show file tree

Hide file tree

Showing 2 changed files with 40 additions and 1 deletion.
diff --git a/src/main/mondrian/olap/fun/NativizeSetFunDef.java b/src/main/mondrian/olap/fun/NativizeSetFunDef.java
@@ -311,7 +311,7 @@ private boolean isHighCardinality(
                     Level hierarchyLevel =
                         Util.lookupHierarchyLevel(hierarchy, levelName);
                     long levelCardinality =
-                        schema.getLevelCardinality(hierarchyLevel, false, true);
+                        getLevelCardinality(schema, hierarchyLevel);
                     estimatedCardinality *= levelCardinality;
                     if (estimatedCardinality >= nativizeMinThreshold) {
                         LOGGER.info(
@@ -338,6 +338,17 @@ private boolean isHighCardinality(
             return isHighCardinality;
         }
 
+        private long getLevelCardinality(SchemaReader schema, Level level) {
+            if (cardinalityIsKnown(level)) {
+                return level.getApproxRowCount();
+            }
+            return schema.getLevelCardinality(level, false, true);
+        }
+
+        private boolean cardinalityIsKnown(Level level) {
+            return level.getApproxRowCount() > 0;
+        }
+
         private Iterable<?> evaluateJoinExpression(
             Evaluator evaluator, String crossJoinExpression)
         {

diff --git a/testsrc/main/mondrian/olap/fun/NativizeSetFunDefTest.java b/testsrc/main/mondrian/olap/fun/NativizeSetFunDefTest.java
@@ -1368,6 +1368,34 @@ public void testLeafMembersOfParentChildDimensionAreNativelyEvaluated() {
             + ")) on 0 from hr");
     }
 
+    public void testCardinalityQueriesOnlyExecuteOnce() {
+        SqlPattern[] patterns = {
+            new SqlPattern(
+                Dialect.DatabaseProduct.ORACLE,
+                "select count(*) as \"c0\" "
+                    + "from (select "
+                    + "distinct \"customer\".\"gender\" as \"c0\" "
+                    + "from \"customer\" \"customer\") \"init\"",
+                108),
+            new SqlPattern(
+                Dialect.DatabaseProduct.ACCESS,
+                "select count(*) as `c0` "
+                    + "from (select "
+                    + "distinct `customer`.`gender` as `c0` "
+                    + "from `customer` as `customer`) as `init`",
+                108)
+        };
+        String mdxQuery =
+            "select"
+                + " non empty"
+                + " NativizeSet(Crossjoin("
+                + "[Gender].[Gender].members,[Marital Status].[Marital Status].members"
+                + ")) on 0 from Sales";
+        getConnection().execute(getConnection().parseQuery(mdxQuery));
+        assertQuerySqlOrNot(
+            getTestContext(), mdxQuery, patterns, true, false, false);
+    }
+
     // ~ ====== Helper methods =================================================
 
     private void checkNotNative(String mdx) {