cassandra-trunk/tools/stress/src/org/apache/cassandra/stress/Stress.java
/**
 * 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.cassandra.stress;

import java.io.*;

import org.apache.cassandra.config.DatabaseDescriptor;
import org.apache.cassandra.stress.settings.StressSettings;
import org.apache.cassandra.stress.util.MultiResultLogger;
import org.apache.commons.lang3.exception.ExceptionUtils;

public final class Stress
{

    /**
     * Known issues:
     * - uncertainty/stderr assumes op-rates are normally distributed. Due to GC (and possibly latency stepping from
     * different media, though the variance of request ratio across media should be normally distributed), they are not.
     * Should attempt to account for pauses in stderr calculation, possibly by assuming these pauses are a separate
     * normally distributed occurrence
     * - Under very mixed work loads, the uncertainty calculations and op/s reporting really don't mean much. Should
     * consider breaking op/s down per workload, or should have a lower-bound on inspection interval based on clustering
     * of operations and thread count.
     *
     *
     * Future improvements:
     * - Configurable connection compression
     * - Java driver support
     * - Per column data generators
     * - Automatic column/schema detection if provided with a CF
     * - target rate produces a very steady work rate, and if we want to simulate a real op rate for an
     *   application we should have some variation in the actual op rate within any time-slice.
     * - auto rate should vary the thread count based on performance improvement, potentially starting on a very low
     *   thread count with a high error rate / low count to get some basic numbers
     */

    public static void main(String[] arguments) throws Exception
    {
        System.exit(run(arguments));
    }

    private static int run(String[] arguments)
    {
        try
        {
            DatabaseDescriptor.clientInitialization();

            final StressSettings settings;
            try
            {
                settings = StressSettings.parse(arguments);
                if (settings == null)
                    return 0; // special settings action
            }
            catch (IllegalArgumentException e)
            {
                System.out.printf("%s%n", e.getMessage());
                printHelpMessage();
                return 1;
            }
            catch (Throwable e)
            {
            	Throwable rc = ExceptionUtils.getRootCause(e);
            	if (rc instanceof FileNotFoundException)
            	{
                    System.out.printf("File '%s' doesn't exist!%n", rc.getMessage());
                    printHelpMessage();
                    return 1;
            	}
            	throw e;
            }

            MultiResultLogger logout = settings.log.getOutput();

            if (! settings.log.noSettings)
            {
                settings.printSettings(logout);
            }

            if (settings.graph.inGraphMode())
            {
                logout.addStream(new PrintStream(settings.graph.temporaryLogFile));
            }

            StressAction stressAction = new StressAction(settings, logout);
            stressAction.run();
            logout.flush();
            if (settings.graph.inGraphMode())
                new StressGraph(settings, arguments).generateGraph();
        }
        catch (Throwable t)
        {
            t.printStackTrace();
            return 1;
        }

        return 0;
    }

    /**
     * Printing out help message
     */
    public static void printHelpMessage()
    {
        StressSettings.printHelp();
    }
}
