use threadlocal random generator to avoid contention

src/main/java/com/oltpbenchmark/benchmarks/tpcc/TPCCLoader.java

@@ -22,6 +22,7 @@
 import com.oltpbenchmark.api.LoaderThread;
 import com.oltpbenchmark.benchmarks.tpcc.pojo.*;
 import com.oltpbenchmark.catalog.Table;
+import com.oltpbenchmark.util.ThreadLocalRandomGenerator;
 import com.oltpbenchmark.util.SQLUtil;
 
 import java.sql.*;

src/main/java/com/oltpbenchmark/benchmarks/tpcc/TPCCUtil.java

@@ -19,7 +19,7 @@
 package com.oltpbenchmark.benchmarks.tpcc;
 
 import com.oltpbenchmark.benchmarks.tpcc.pojo.Customer;
-import com.oltpbenchmark.util.RandomGenerator;
+import com.oltpbenchmark.util.ThreadLocalRandomGenerator;
 
 import java.sql.ResultSet;
 import java.sql.SQLException;
@@ -59,7 +59,7 @@ public static Customer newCustomerFromResults(ResultSet rs)
         return c;
     }
 
-    private static final RandomGenerator ran = new RandomGenerator(0);
+    private static final ThreadLocalRandomGenerator ran = new ThreadLocalRandomGenerator();
 
     public static String randomStr(int strLen) {
         if (strLen > 1) {

src/main/java/com/oltpbenchmark/util/ThreadLocalRandomGenerator.java

@@ -0,0 +1,124 @@
+/*
+ * Copyright 2023 by OLTPBenchmark Project
+ *
+ * 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.
+ *
+ */
+
+
+ package com.oltpbenchmark.util;
+
+ import java.util.concurrent.ThreadLocalRandom;
+
+ public class ThreadLocalRandomGenerator {
+
+     /**
+      * Constructor
+      *
+      * @param seed
+      */
+     public ThreadLocalRandomGenerator() {
+     }
+
+     /**
+      * Returns a random int value between minimum and maximum (inclusive)
+      *
+      * @param minimum
+      * @param maximum
+      * @returns a int in the range [minimum, maximum]. Note that this is inclusive.
+      */
+     public int number(int minimum, int maximum) {
+
+         int range_size = maximum - minimum + 1;
+         int value = ThreadLocalRandom.current().nextInt(range_size);
+         value += minimum;
+
+         return value;
+     }
+
+     /**
+      * Returns a random long value between minimum and maximum (inclusive)
+      *
+      * @param minimum
+      * @param maximum
+      * @return
+      */
+     public long number(long minimum, long maximum) {
+
+         long range_size = (maximum - minimum) + 1;
+
+         // error checking and 2^x checking removed for simplicity.
+         long bits, val;
+         do {
+             bits = (ThreadLocalRandom.current().nextLong() << 1) >>> 1;
+             val = bits % range_size;
+         }
+         while (bits - val + range_size < 0L);
+         val += minimum;
+
+
+         return val;
+     }
+
+     /**
+      * @param decimal_places
+      * @param minimum
+      * @param maximum
+      * @return
+      */
+     public double fixedPoint(int decimal_places, double minimum, double maximum) {
+
+
+         int multiplier = 1;
+         for (int i = 0; i < decimal_places; ++i) {
+             multiplier *= 10;
+         }
+
+         int int_min = (int) (minimum * multiplier + 0.5);
+         int int_max = (int) (maximum * multiplier + 0.5);
+
+         return (double) this.number(int_min, int_max) / (double) multiplier;
+     }
+
+     /**
+      * @returns a random alphabetic string with length in range [minimum_length, maximum_length].
+      */
+     public String astring(int minimum_length, int maximum_length) {
+         return randomString(minimum_length, maximum_length, 'a', 26);
+     }
+
+
+     /**
+      * @returns a random numeric string with length in range [minimum_length, maximum_length].
+      */
+     public String nstring(int minimum_length, int maximum_length) {
+         return randomString(minimum_length, maximum_length, '0', 10);
+     }
+
+     /**
+      * @param minimum_length
+      * @param maximum_length
+      * @param base
+      * @param numCharacters
+      * @return
+      */
+     private String randomString(int minimum_length, int maximum_length, char base, int numCharacters) {
+         int length = number(minimum_length, maximum_length);
+         byte baseByte = (byte) base;
+         byte[] bytes = new byte[length];
+         for (int i = 0; i < length; ++i) {
+             bytes[i] = (byte) (baseByte + number(0, numCharacters - 1));
+         }
+         return new String(bytes);
+     }
+ }