Fixed issue 204.

git-svn-id: https://asterixdb.googlecode.com/svn/branches/asterix_stabilization@762 eaa15691-b419-025a-1212-ee371bd00084
diff --git a/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/am/OptimizableOperatorSubTree.java b/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/am/OptimizableOperatorSubTree.java
index 80f8cc1..92acd8b 100644
--- a/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/am/OptimizableOperatorSubTree.java
+++ b/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/am/OptimizableOperatorSubTree.java
@@ -27,8 +27,8 @@
  * (select)? <-- (datasource scan)
  */
 public class OptimizableOperatorSubTree {
-    public ILogicalOperator root;
-    public Mutable<ILogicalOperator> rootRef;
+    public ILogicalOperator root = null;
+    public Mutable<ILogicalOperator> rootRef = null;
     public final List<Mutable<ILogicalOperator>> assignRefs = new ArrayList<Mutable<ILogicalOperator>>();
     public final List<AssignOperator> assigns = new ArrayList<AssignOperator>();
     public Mutable<ILogicalOperator> dataSourceScanRef = null;
@@ -38,6 +38,7 @@
     public ARecordType recordType = null;
 
     public boolean initFromSubTree(Mutable<ILogicalOperator> subTreeOpRef) {
+        reset();
         rootRef = subTreeOpRef;
         root = subTreeOpRef.getValue();
         // Examine the op's children to match the expected patterns.
@@ -111,4 +112,15 @@
     public boolean hasDataSourceScan() {
         return dataSourceScan != null;
     }
+    
+    public void reset() {
+        assignRefs.clear();
+        assigns.clear();
+        root = null;
+        rootRef = null;
+        dataSourceScanRef = null;
+        dataSourceScan = null;
+        dataset = null;
+        recordType = null;
+    }
 }
diff --git a/asterix-app/src/test/resources/runtimets/queries/index-selection/btree-index-rewrite-multiple.aql b/asterix-app/src/test/resources/runtimets/queries/index-selection/btree-index-rewrite-multiple.aql
new file mode 100644
index 0000000..7b72a80
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/queries/index-selection/btree-index-rewrite-multiple.aql
@@ -0,0 +1,48 @@
+/*
+ * Description     : Test that multiple subtrees in the same query
+ *                   can be rewritten with secondary BTree indexes.
+ *                   Guards against regression to issue 204.
+ * Expected Result : Success
+ * Issue           : Issue 204
+ */
+ 
+drop dataverse tpch if exists;
+create dataverse tpch;
+use dataverse tpch;
+
+create type OrderType as open {
+  o_orderkey: int32, 
+  o_custkey: int32, 
+  o_orderstatus: string, 
+  o_totalprice: double, 
+  o_orderdate: string, 
+  o_orderpriority: string,
+  o_clerk: string, 
+  o_shippriority: int32, 
+  o_comment: string
+}
+
+create dataset Orders(OrderType) partitioned by key o_orderkey;
+
+load dataset Orders 
+using "edu.uci.ics.asterix.external.dataset.adapter.NCFileSystemAdapter"
+(("path"="nc1://data/tpch0.001/orders.tbl"),("format"="delimited-text"),("delimiter"="|")) pre-sorted;
+
+create index idx_Orders_Custkey on Orders(o_custkey);
+
+write output to nc1:"rttest/index-selection_btree-index-rewrite-multiple.adm";
+
+for $o in dataset('Orders')
+for $o2 in dataset('Orders')
+where $o.o_custkey = 20 and $o2.o_custkey = 10
+and $o.o_orderstatus < $o2.o_orderstatus
+order by $o.o_orderkey, $o2.o_orderkey
+return {
+  "o_orderkey": $o.o_orderkey,
+  "o_custkey": $o.o_custkey,
+  "o_orderstatus": $o.o_orderstatus,
+  "o_orderkey2": $o2.o_orderkey,
+  "o_custkey2": $o2.o_custkey,
+  "o_orderstatus2": $o2.o_orderstatus
+}
+ 
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/results/index-selection/btree-index-rewrite-multiple.adm b/asterix-app/src/test/resources/runtimets/results/index-selection/btree-index-rewrite-multiple.adm
new file mode 100644
index 0000000..3bf46e6
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/results/index-selection/btree-index-rewrite-multiple.adm
@@ -0,0 +1,18 @@
+{ "o_orderkey": 1188, "o_custkey": 20, "o_orderstatus": "O", "o_orderkey2": 3911, "o_custkey2": 10, "o_orderstatus2": "P" }
+{ "o_orderkey": 1377, "o_custkey": 20, "o_orderstatus": "O", "o_orderkey2": 3911, "o_custkey2": 10, "o_orderstatus2": "P" }
+{ "o_orderkey": 1378, "o_custkey": 20, "o_orderstatus": "O", "o_orderkey2": 3911, "o_custkey2": 10, "o_orderstatus2": "P" }
+{ "o_orderkey": 3042, "o_custkey": 20, "o_orderstatus": "F", "o_orderkey2": 227, "o_custkey2": 10, "o_orderstatus2": "O" }
+{ "o_orderkey": 3042, "o_custkey": 20, "o_orderstatus": "F", "o_orderkey2": 517, "o_custkey2": 10, "o_orderstatus2": "O" }
+{ "o_orderkey": 3042, "o_custkey": 20, "o_orderstatus": "F", "o_orderkey2": 1223, "o_custkey2": 10, "o_orderstatus2": "O" }
+{ "o_orderkey": 3042, "o_custkey": 20, "o_orderstatus": "F", "o_orderkey2": 1860, "o_custkey2": 10, "o_orderstatus2": "O" }
+{ "o_orderkey": 3042, "o_custkey": 20, "o_orderstatus": "F", "o_orderkey2": 1890, "o_custkey2": 10, "o_orderstatus2": "O" }
+{ "o_orderkey": 3042, "o_custkey": 20, "o_orderstatus": "F", "o_orderkey2": 3428, "o_custkey2": 10, "o_orderstatus2": "O" }
+{ "o_orderkey": 3042, "o_custkey": 20, "o_orderstatus": "F", "o_orderkey2": 3618, "o_custkey2": 10, "o_orderstatus2": "O" }
+{ "o_orderkey": 3042, "o_custkey": 20, "o_orderstatus": "F", "o_orderkey2": 3843, "o_custkey2": 10, "o_orderstatus2": "O" }
+{ "o_orderkey": 3042, "o_custkey": 20, "o_orderstatus": "F", "o_orderkey2": 3911, "o_custkey2": 10, "o_orderstatus2": "P" }
+{ "o_orderkey": 3042, "o_custkey": 20, "o_orderstatus": "F", "o_orderkey2": 4032, "o_custkey2": 10, "o_orderstatus2": "O" }
+{ "o_orderkey": 3042, "o_custkey": 20, "o_orderstatus": "F", "o_orderkey2": 4097, "o_custkey2": 10, "o_orderstatus2": "O" }
+{ "o_orderkey": 3042, "o_custkey": 20, "o_orderstatus": "F", "o_orderkey2": 4388, "o_custkey2": 10, "o_orderstatus2": "O" }
+{ "o_orderkey": 3042, "o_custkey": 20, "o_orderstatus": "F", "o_orderkey2": 4421, "o_custkey2": 10, "o_orderstatus2": "O" }
+{ "o_orderkey": 3042, "o_custkey": 20, "o_orderstatus": "F", "o_orderkey2": 4449, "o_custkey2": 10, "o_orderstatus2": "O" }
+{ "o_orderkey": 3042, "o_custkey": 20, "o_orderstatus": "F", "o_orderkey2": 5123, "o_custkey2": 10, "o_orderstatus2": "O" }
\ No newline at end of file