Github user vrozov commented on a diff in the pull request:
https://github.com/apache/drill/pull/1110#discussion_r167587159
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/physical/config/OrderedMuxExchange.java
---
@@ -0,0 +1,64 @@
+/**
+ * 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.drill.exec.physical.config;
+
+import java.util.List;
+
+import org.apache.drill.exec.physical.MinorFragmentEndpoint;
+import org.apache.drill.exec.physical.base.PhysicalOperator;
+import org.apache.drill.exec.physical.base.Receiver;
+import org.apache.drill.common.logical.data.Order.Ordering;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+
+/**
+ * OrderedMuxExchange is a version of MuxExchange where the incoming
batches are sorted
+ * merge operation is performed to produced a sorted stream as output.
+ */
+@JsonTypeName("ordered-mux-exchange")
+public class OrderedMuxExchange extends AbstractMuxExchange {
+ private static final org.slf4j.Logger logger =
org.slf4j.LoggerFactory.getLogger(OrderedMuxExchange.class);
+
+ private final List<Ordering> orderings;
+
+ public OrderedMuxExchange(@JsonProperty("child") PhysicalOperator child,
@JsonProperty("orderings")List<Ordering> orderings) {
+ super(child);
+ this.orderings = orderings;
+ }
+
+ @Override
+ public Receiver getReceiver(int minorFragmentId) {
+ createSenderReceiverMapping();
+
+ List<MinorFragmentEndpoint> senders =
receiverToSenderMapping.get(minorFragmentId);
+ if (senders == null || senders.size() <= 0) {
+ throw new IllegalStateException(String.format("Failed to find
senders for receiver [%d]", minorFragmentId));
+ }
+
+ if (logger.isDebugEnabled()) {
+ logger.debug(String.format("Minor fragment %d, receives data from
following senders %s", minorFragmentId, senders));
--- End diff --
Use smart SLF4J logging, remove `isDebugEnabled()` check, consider moving
logging prior to the exception.
---
