add ability to specify field length distributions

src/com/yahoo/ycsb/generator/ConstantIntegerGenerator.java

+/**
+ * Copyright (c) 2010 Yahoo! Inc. 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.generator;
+
+/**
+ * A trivial integer generator that always returns the same value.
+ * 
+ * @author sears
+ *
+ */
+public class ConstantIntegerGenerator extends IntegerGenerator {
+	private final int i;
+	/**
+	 * @param i The integer that this generator will always return.
+	 */
+	public ConstantIntegerGenerator(int i) {
+		this.i = i;
+	}
+
+	@Override
+	public int nextInt() {
+		return i;
+	}
+
+	@Override
+	public double mean() {
+		return i;
+	}
+
+}

src/com/yahoo/ycsb/generator/CounterGenerator.java

@@ -45,5 +45,8 @@ public class CounterGenerator extends IntegerGenerator
 		return lastint;
 	}
 
-
+	@Override
+	public double mean() {
+		throw new UnsupportedOperationException("Can't compute mean of non-stationary distribution!");
+	}
 }

src/com/yahoo/ycsb/generator/HistogramGenerator.java

+/**
+ * Copyright (c) 2010 Yahoo! Inc. 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.generator;
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Random;
+import com.yahoo.ycsb.generator.IntegerGenerator;
+
+/**
+ * Generate integers according to a histogram distribution.  The histogram
+ * buckets are of width one, but the values are multiplied by a block size.
+ * Therefore, instead of drawing sizes uniformly at random within each
+ * bucket, we always draw the largest value in the current bucket, so the value
+ * drawn is always a multiple of block_size.
+ * 
+ * The minimum value this distribution returns is block_size (not zero).
+ * 
+ * Modified Nov 19 2010 by sears
+ * 
+ * @author snjones
+ *
+ */
+public class HistogramGenerator extends IntegerGenerator {
+
+	long block_size;
+	long[] buckets;
+	long area;
+	Random rand = new Random();
+	long weighted_area = 0;
+	double mean_size = 0;
+	
+	public HistogramGenerator(String histogramfile) throws IOException {
+	BufferedReader in = new BufferedReader(new FileReader(histogramfile));
+	String str;
+	String[] line;
+	
+	ArrayList<Integer> a = new ArrayList<Integer>();
+
+	str = in.readLine();
+	if(str == null) {
+		throw new IOException("Empty input file!\n");
+	}
+	line = str.split("\t");
+	if(line[0].compareTo("BlockSize") != 0) {
+		throw new IOException("First line of histogram is not the BlockSize!\n");
+	}
+	block_size = Integer.parseInt(line[1]);
+	
+	while((str = in.readLine()) != null){
+		// [0] is the bucket, [1] is the value
+		line = str.split("\t");
+		
+		a.add(Integer.parseInt(line[0]), Integer.parseInt(line[1]));
+	}
+	buckets = new long[a.size()];
+	for(int i = 0; i < a.size(); i++) {
+		buckets[i] = a.get(i);
+	}
+
+	in.close();
+	init();
+	}
+
+	public HistogramGenerator(long[] buckets, int block_size) {
+		this.block_size = block_size;
+		this.buckets = buckets;
+		init();
+	}
+	private void init() {
+		for(int i = 0; i < buckets.length; i++) {
+			area += buckets[i];
+			weighted_area = i * buckets[i];
+		}
+		// calculate average file size
+		mean_size = ((double)block_size) * ((double)weighted_area) / (double)(area);
+	}
+
+	@Override
+	public int nextInt() {
+		int number = rand.nextInt((int)area);
+		int i;
+		
+		for(i = 0; i < (buckets.length - 1); i++){
+			number -= buckets[i];
+			if(number <= 0){
+				return (int)((i+1)*block_size);
+			}
+		}
+		
+		return (int)(i * block_size);
+	}
+
+	@Override
+	public double mean() {
+		return mean_size;
+	}
+}

src/com/yahoo/ycsb/generator/IntegerGenerator.java

@@ -67,4 +67,8 @@ public abstract class IntegerGenerator extends Generator
 	{
 		return lastint;
 	}
+	/**
+	 * Return the expected value (mean) of the values this generator will return.
+	 */
+	public abstract double mean();
 }

src/com/yahoo/ycsb/generator/ScrambledZipfianGenerator.java

@@ -126,4 +126,12 @@ public class ScrambledZipfianGenerator extends IntegerGenerator
 			System.out.println(""+gen.nextInt());
 		}
 	}
+
+	/**
+	 * since the values are scrambled (hopefully uniformly), the mean is simply the middle of the range.
+	 */
+	@Override
+	public double mean() {
+		return ((double)(((long)_min) +(long)_max))/2.0;
+	}
 }

src/com/yahoo/ycsb/generator/SkewedLatestGenerator.java

@@ -53,4 +53,9 @@ public class SkewedLatestGenerator extends IntegerGenerator
 
 	}
 
+	@Override
+	public double mean() {
+		throw new UnsupportedOperationException("Can't compute mean of non-stationary distribution!");
+	}
+
 }

src/com/yahoo/ycsb/generator/UniformIntegerGenerator.java

@@ -50,4 +50,8 @@ public class UniformIntegerGenerator extends IntegerGenerator
 		return ret;
 	}
 
+	@Override
+	public double mean() {
+		return ((double)((long)(_lb + (long)_ub))) / 2.0;
+	}
 }

src/com/yahoo/ycsb/generator/ZipfianGenerator.java

@@ -316,4 +316,12 @@ public class ZipfianGenerator extends IntegerGenerator
 	{
 		new ZipfianGenerator(ScrambledZipfianGenerator.ITEM_COUNT);
 	}
+
+	/**
+	 * @todo Implement ZipfianGenerator.mean()
+	 */
+	@Override
+	public double mean() {
+		throw new UnsupportedOperationException("@todo implement ZipfianGenerator.mean()");
+	}
 }

src/com/yahoo/ycsb/workloads/CoreWorkload.java

@@ -22,7 +22,9 @@ import com.yahoo.ycsb.*;
 import com.yahoo.ycsb.generator.CounterGenerator;
 import com.yahoo.ycsb.generator.DiscreteGenerator;
 import com.yahoo.ycsb.generator.Generator;
+import com.yahoo.ycsb.generator.ConstantIntegerGenerator;
 import com.yahoo.ycsb.generator.HotspotIntegerGenerator;
+import com.yahoo.ycsb.generator.HistogramGenerator;
 import com.yahoo.ycsb.generator.IntegerGenerator;
 import com.yahoo.ycsb.generator.ScrambledZipfianGenerator;
 import com.yahoo.ycsb.generator.SkewedLatestGenerator;
@@ -30,6 +32,7 @@ import com.yahoo.ycsb.generator.UniformIntegerGenerator;
 import com.yahoo.ycsb.generator.ZipfianGenerator;
 import com.yahoo.ycsb.measurements.Measurements;
 
+import java.io.IOException;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Vector;
@@ -84,18 +87,41 @@ public class CoreWorkload extends Workload
 
 	int fieldcount;
 
+	/**
+	 * The name of the property for the field length distribution. Options are "uniform", "zipfian" (favoring short records), "constant", and "histogram".
+	 * 
+	 * If "uniform", "zipfian" or "constant", the maximum field length will be that specified by the fieldlength property.  If "histogram", then the
+	 * histogram will be read from the filename specified in the "fieldlengthhistogram" property.
+	 */
+	public static final String FIELD_LENGTH_DISTRIBUTION_PROPERTY="fieldlengthdistribution";
+	/**
+	 * The default field length distribution.
+	 */
+	public static final String FIELD_LENGTH_DISTRIBUTION_PROPERTY_DEFAULT = "constant";
+
 	/**
 	 * The name of the property for the length of a field in bytes.
 	 */
 	public static final String FIELD_LENGTH_PROPERTY="fieldlength";
-	
 	/**
-	 * The default length of a field in bytes.
+	 * The default maximum length of a field in bytes.
 	 */
 	public static final String FIELD_LENGTH_PROPERTY_DEFAULT="100";
 
-	int fieldlength;
+	/**
+	 * The name of a property that specifies the filename containing the field length histogram (only used if fieldlengthdistribution is "histogram").
+	 */
+	public static final String FIELD_LENGTH_HISTOGRAM_FILE_PROPERTY = "fieldlengthhistogram";
+	/**
+	 * The default filename containing a field length histogram.
+	 */
+	public static final String FIELD_LENGTH_HISTOGRAM_FILE_PROPERTY_DEFAULT = "hist.txt";
 
+	/**
+	 * Generator object that produces field lengths.  The value of this depends on the properties that start with "FIELD_LENGTH_".
+	 */
+	IntegerGenerator fieldlengthgenerator;
+	
 	/**
 	 * The name of the property for deciding whether to read one field (false) or all fields (true) of a record.
 	 */
@@ -247,6 +273,29 @@ public class CoreWorkload extends Workload
 
 	int recordcount;
 	
+	protected static IntegerGenerator getFieldLengthGenerator(Properties p) throws WorkloadException{
+		IntegerGenerator fieldlengthgenerator;
+		String fieldlengthdistribution = p.getProperty(FIELD_LENGTH_DISTRIBUTION_PROPERTY, FIELD_LENGTH_DISTRIBUTION_PROPERTY_DEFAULT);
+		int fieldlength=Integer.parseInt(p.getProperty(FIELD_LENGTH_PROPERTY,FIELD_LENGTH_PROPERTY_DEFAULT));
+		String fieldlengthhistogram = p.getProperty(FIELD_LENGTH_HISTOGRAM_FILE_PROPERTY, FIELD_LENGTH_HISTOGRAM_FILE_PROPERTY_DEFAULT);
+		if(fieldlengthdistribution.compareTo("constant") == 0) {
+			fieldlengthgenerator = new ConstantIntegerGenerator(fieldlength);
+		} else if(fieldlengthdistribution.compareTo("uniform") == 0) {
+			fieldlengthgenerator = new UniformIntegerGenerator(1, fieldlength);
+		} else if(fieldlengthdistribution.compareTo("zipfian") == 0) {
+			fieldlengthgenerator = new ZipfianGenerator(1, fieldlength);
+		} else if(fieldlengthdistribution.compareTo("histogram") == 0) {
+			try {
+				fieldlengthgenerator = new HistogramGenerator(fieldlengthhistogram);
+			} catch(IOException e) {
+				throw new WorkloadException("Couldn't read field length histogram file: "+fieldlengthhistogram, e);
+			}
+		} else {
+			throw new WorkloadException("Unknown field length distribution \""+fieldlengthdistribution+"\"");
+		}
+		return fieldlengthgenerator;
+	}
+	
 	/**
 	 * Initialize the scenario. 
 	 * Called once, in the main client thread, before any operations are started.
@@ -254,8 +303,10 @@ public class CoreWorkload extends Workload
 	public void init(Properties p) throws WorkloadException
 	{
 		table = p.getProperty(TABLENAME_PROPERTY,TABLENAME_PROPERTY_DEFAULT);
-		fieldcount=Integer.parseInt(p.getProperty(FIELD_COUNT_PROPERTY,FIELD_COUNT_PROPERTY_DEFAULT));
-		fieldlength=Integer.parseInt(p.getProperty(FIELD_LENGTH_PROPERTY,FIELD_LENGTH_PROPERTY_DEFAULT));
+		
+		int fieldcount=Integer.parseInt(p.getProperty(FIELD_COUNT_PROPERTY,FIELD_COUNT_PROPERTY_DEFAULT));
+		fieldlengthgenerator = CoreWorkload.getFieldLengthGenerator(p);
+		
 		double readproportion=Double.parseDouble(p.getProperty(READ_PROPORTION_PROPERTY,READ_PROPORTION_PROPERTY_DEFAULT));
 		double updateproportion=Double.parseDouble(p.getProperty(UPDATE_PROPORTION_PROPERTY,UPDATE_PROPORTION_PROPERTY_DEFAULT));
 		double insertproportion=Double.parseDouble(p.getProperty(INSERT_PROPORTION_PROPERTY,INSERT_PROPORTION_PROPERTY_DEFAULT));
@@ -341,7 +392,7 @@ public class CoreWorkload extends Workload
     }
 		else
 		{
-			throw new WorkloadException("Unknown distribution \""+requestdistrib+"\"");
+			throw new WorkloadException("Unknown request distribution \""+requestdistrib+"\"");
 		}
 
 		fieldchooser=new UniformIntegerGenerator(0,fieldcount-1);
@@ -378,7 +429,7 @@ public class CoreWorkload extends Workload
 		for (int i=0; i<fieldcount; i++)
 		{
 			String fieldkey="field"+i;
-			String data=Utils.ASCIIString(fieldlength);
+			String data=Utils.ASCIIString(fieldlengthgenerator.nextInt());
 			values.put(fieldkey,data);
 		}
 		if (db.insert(table,dbkey,values) == 0)
@@ -486,7 +537,7 @@ public class CoreWorkload extends Workload
 		   for (int i=0; i<fieldcount; i++)
 		   {
 		      String fieldname="field"+i;
-		      String data=Utils.ASCIIString(fieldlength);		   
+		      String data=Utils.ASCIIString(fieldlengthgenerator.nextInt());
 		      values.put(fieldname,data);
 		   }
 		}
@@ -494,7 +545,7 @@ public class CoreWorkload extends Workload
 		{
 		   //update a random field
 		   String fieldname="field"+fieldchooser.nextString();
-		   String data=Utils.ASCIIString(fieldlength);		   
+		   String data=Utils.ASCIIString(fieldlengthgenerator.nextInt());
 		   values.put(fieldname,data);
 		}
 
@@ -568,7 +619,7 @@ public class CoreWorkload extends Workload
 		   for (int i=0; i<fieldcount; i++)
 		   {
 		      String fieldname="field"+i;
-		      String data=Utils.ASCIIString(fieldlength);		   
+		      String data=Utils.ASCIIString(fieldlengthgenerator.nextInt());
 		      values.put(fieldname,data);
 		   }
 		}
@@ -576,7 +627,7 @@ public class CoreWorkload extends Workload
 		{
 		   //update a random field
 		   String fieldname="field"+fieldchooser.nextString();
-		   String data=Utils.ASCIIString(fieldlength);		   
+		   String data=Utils.ASCIIString(fieldlengthgenerator.nextInt());
 		   values.put(fieldname,data);
 		}
 
@@ -597,7 +648,7 @@ public class CoreWorkload extends Workload
 		for (int i=0; i<fieldcount; i++)
 		{
 			String fieldkey="field"+i;
-			String data=Utils.ASCIIString(fieldlength);
+			String data=Utils.ASCIIString(fieldlengthgenerator.nextInt());
 			values.put(fieldkey,data);
 		}
 		db.insert(table,dbkey,values);