[NO ISSUE][*DB] Prevent Cancellation for DMLs

- user model changes: The only cancellable jobs are queries.
- storage format changes: no
- interface changes: no

details:
- Before this change, DML jobs were added to the job execution
  context.
- This job passes a dummy job execution context to disallow
  registration and cancellation of DMLs.

Change-Id: I3bb1a737c6ec6dd5a79fc25db25325ab60d838b9
Reviewed-on: https://asterix-gerrit.ics.uci.edu/1977
Sonar-Qube: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Integration-Tests: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Tested-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Reviewed-by: Michael Blow <mblow@apache.org>
diff --git a/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/translator/NoOpStatementExecutorContext.java b/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/translator/NoOpStatementExecutorContext.java
new file mode 100644
index 0000000..ec181bb
--- /dev/null
+++ b/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/translator/NoOpStatementExecutorContext.java
@@ -0,0 +1,45 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.asterix.translator;
+
+import org.apache.hyracks.api.job.JobId;
+
+public class NoOpStatementExecutorContext implements IStatementExecutorContext {
+
+    public static final NoOpStatementExecutorContext INSTANCE = new NoOpStatementExecutorContext();
+
+    private NoOpStatementExecutorContext() {
+    }
+
+    @Override
+    public JobId getJobIdFromClientContextId(String clientContextId) {
+        return null;
+    }
+
+    @Override
+    public void put(String clientContextId, JobId jobId) {
+        // Dummy for when a statement doesn't support cancellation
+    }
+
+    @Override
+    public JobId removeJobIdFromClientContextId(String clientContextId) {
+        return null;
+    }
+
+}
diff --git a/asterixdb/asterix-app/src/main/java/org/apache/asterix/app/translator/QueryTranslator.java b/asterixdb/asterix-app/src/main/java/org/apache/asterix/app/translator/QueryTranslator.java
index b97c014..e0d56a0 100644
--- a/asterixdb/asterix-app/src/main/java/org/apache/asterix/app/translator/QueryTranslator.java
+++ b/asterixdb/asterix-app/src/main/java/org/apache/asterix/app/translator/QueryTranslator.java
@@ -162,6 +162,7 @@
 import org.apache.asterix.translator.CompiledStatements.ICompiledDmlStatement;
 import org.apache.asterix.translator.IStatementExecutor;
 import org.apache.asterix.translator.IStatementExecutorContext;
+import org.apache.asterix.translator.NoOpStatementExecutorContext;
 import org.apache.asterix.translator.SessionConfig;
 import org.apache.asterix.translator.SessionOutput;
 import org.apache.asterix.translator.TypeTranslator;
@@ -334,7 +335,7 @@
                                     || resultDelivery == ResultDelivery.DEFERRED);
                         }
                         handleInsertUpsertStatement(metadataProvider, stmt, hcc, hdc, resultDelivery, outMetadata,
-                                stats, false, clientContextId, ctx);
+                                stats, false, clientContextId);
                         break;
                     case Statement.Kind.DELETE:
                         handleDeleteStatement(metadataProvider, stmt, hcc, false);
@@ -1727,8 +1728,7 @@
 
     public JobSpecification handleInsertUpsertStatement(MetadataProvider metadataProvider, Statement stmt,
             IHyracksClientConnection hcc, IHyracksDataset hdc, ResultDelivery resultDelivery,
-            ResultMetadata outMetadata, Stats stats, boolean compileOnly, String clientContextId,
-            IStatementExecutorContext ctx) throws Exception {
+            ResultMetadata outMetadata, Stats stats, boolean compileOnly, String clientContextId) throws Exception {
         InsertStatement stmtInsertUpsert = (InsertStatement) stmt;
         String dataverseName = getActiveDataverse(stmtInsertUpsert.getDataverseName());
         final IMetadataLocker locker = new IMetadataLocker() {
@@ -1771,7 +1771,7 @@
 
         if (stmtInsertUpsert.getReturnExpression() != null) {
             deliverResult(hcc, hdc, compiler, metadataProvider, locker, resultDelivery, outMetadata, stats,
-                    clientContextId, ctx);
+                    clientContextId, NoOpStatementExecutorContext.INSTANCE);
         } else {
             locker.lock();
             try {