/**
* 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.ops;
import java.util.concurrent.Semaphore;
import java.util.concurrent.atomic.AtomicInteger;
/**
* Account for whether all messages sent have been completed. Necessary before finishing a task so we don't think
* buffers are hanging when they will be released.
*
* TODO: Need to update to use long for number of pending messages.
*/
class SendingAccountor {
private static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(SendingAccountor.class);
private final AtomicInteger batchesSent = new AtomicInteger(0);
private final Semaphore wait = new Semaphore(0);
void increment() {
batchesSent.incrementAndGet();
}
void decrement() {
wait.release();
}
public synchronized void waitForSendComplete() {
int waitForBatches = batchesSent.get();
boolean isInterrupted = false;
while(waitForBatches != 0) {
try {
wait.acquire(waitForBatches);
waitForBatches = batchesSent.addAndGet(-1 * waitForBatches);
} catch (InterruptedException e) {
// We should always wait for send complete. If we don't, we'll leak memory or have a memory miss when we try
// to send. This should be safe because: network connections should get disconnected and fail a send if a
// node goes down, otherwise, the receiving side connection should always consume from the rpc layer
// (blocking is cooperative and will get triggered before this)
logger.warn("Interrupted while waiting for send complete. Continuing to wait.", e);
isInterrupted = true;
}
}
if (isInterrupted) {
// Preserve evidence that the interruption occurred so that code higher up on the call stack can learn of the
// interruption and respond to it if it wants to.
Thread.currentThread().interrupt();
}
}
}