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Workload.java
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Sat, Aug 24, 18:28

Workload.java
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/**
* Copyright (c) 2010-2016 Yahoo! Inc., 2017 YCSB contributors All rights reserved.
*
* Licensed 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. See accompanying
* LICENSE file.
*/
package com.yahoo.ycsb;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.Properties;
/**
* One experiment scenario. One object of this type will
* be instantiated and shared among all client threads. This class
* should be constructed using a no-argument constructor, so we can
* load it dynamically. Any argument-based initialization should be
* done by init().
*
* If you extend this class, you should support the "insertstart" property. This
* allows the Client to proceed from multiple clients on different machines, in case
* the client is the bottleneck. For example, if we want to load 1 million records from
* 2 machines, the first machine should have insertstart=0 and the second insertstart=500000. Additionally,
* the "insertcount" property, which is interpreted by Client, can be used to tell each instance of the
* client how many inserts to do. In the example above, both clients should have insertcount=500000.
*/
public abstract class Workload {
public static final String INSERT_START_PROPERTY = "insertstart";
public static final String INSERT_COUNT_PROPERTY = "insertcount";
public static final String INSERT_START_PROPERTY_DEFAULT = "0";
private volatile AtomicBoolean stopRequested = new AtomicBoolean(false);
/** Operations available for a database. */
public enum Operation {
READ,
UPDATE,
INSERT,
SCAN,
DELETE
}
/**
* Initialize the scenario. Create any generators and other shared objects here.
* Called once, in the main client thread, before any operations are started.
*/
public void init(Properties p) throws WorkloadException {
}
/**
* Initialize any state for a particular client thread. Since the scenario object
* will be shared among all threads, this is the place to create any state that is specific
* to one thread. To be clear, this means the returned object should be created anew on each
* call to initThread(); do not return the same object multiple times.
* The returned object will be passed to invocations of doInsert() and doTransaction()
* for this thread. There should be no side effects from this call; all state should be encapsulated
* in the returned object. If you have no state to retain for this thread, return null. (But if you have
* no state to retain for this thread, probably you don't need to override initThread().)
*
* @return false if the workload knows it is done for this thread. Client will terminate the thread.
* Return true otherwise. Return true for workloads that rely on operationcount. For workloads that read
* traces from a file, return true when there are more to do, false when you are done.
*/
public Object initThread(Properties p, int mythreadid, int threadcount) throws WorkloadException {
return null;
}
/**
* Cleanup the scenario. Called once, in the main client thread, after all operations have completed.
*/
public void cleanup() throws WorkloadException {
}
/**
* Do one insert operation. Because it will be called concurrently from multiple client threads, this
* function must be thread safe. However, avoid synchronized, or the threads will block waiting for each
* other, and it will be difficult to reach the target throughput. Ideally, this function would have no side
* effects other than DB operations and mutations on threadstate. Mutations to threadstate do not need to be
* synchronized, since each thread has its own threadstate instance.
*/
public abstract boolean doInsert(DB db, Object threadstate);
/**
* Do one transaction operation. Because it will be called concurrently from multiple client threads, this
* function must be thread safe. However, avoid synchronized, or the threads will block waiting for each
* other, and it will be difficult to reach the target throughput. Ideally, this function would have no side
* effects other than DB operations and mutations on threadstate. Mutations to threadstate do not need to be
* synchronized, since each thread has its own threadstate instance.
*
* @return false if the workload knows it is done for this thread. Client will terminate the thread.
* Return true otherwise. Return true for workloads that rely on operationcount. For workloads that read
* traces from a file, return true when there are more to do, false when you are done.
*/
public abstract boolean doTransaction(DB db, Object threadstate);
/**
* Allows scheduling a request to stop the workload.
*/
public void requestStop() {
stopRequested.set(true);
}
/**
* Check the status of the stop request flag.
* @return true if stop was requested, false otherwise.
*/
public boolean isStopRequested() {
return stopRequested.get();
}
}

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