Java 他告诉我的唯一信息是执行命令后报告的时间

从10000000个元素的mysql提示符来看，排序bigint_值或float_值大约是2.1到2.4

Java JDBC mysql调用（性能类似于从mysql cli进行排序）

五次跑步：

da=2379 ms
da=2361 ms
da=2443 ms
da=2453 ms
da=2362 ms

Java排序动态生成随机数（实际上比磁盘IO读取慢）。赋值时间是生成随机数和填充数组的时间

像打电话一样

JavaSort(10,10000000);

计时结果：

assignment time 331  sort time 1139
assignment time 324  sort time 1037
assignment time 317  sort time 1028
assignment time 319  sort time 1026
assignment time 317  sort time 1018
assignment time 325  sort time 1025
assignment time 317  sort time 1024
assignment time 318  sort time 1054
assignment time 317  sort time 1024
assignment time 317  sort time 1017

这些结果用于在二进制模式下读取double文件

assignment time 4661  sort time 1056
assignment time 4631  sort time 1024
assignment time 4733  sort time 1004
assignment time 4725  sort time 980
assignment time 4635  sort time 980
assignment time 4725  sort time 980
assignment time 4667  sort time 978
assignment time 4668  sort time 980
assignment time 4757  sort time 982
assignment time 4765  sort time 987

执行缓冲区传输会导致更快的运行时

assignment time 77  sort time 1192
assignment time 59  sort time 1125
assignment time 55  sort time 999
assignment time 55  sort time 1000
assignment time 56  sort time 999
assignment time 54  sort time 1010
assignment time 55  sort time 999
assignment time 56  sort time 1000
assignment time 55  sort time 1002
assignment time 56  sort time 1002

C和C++时序结果（参见源代码）

使用qsort调试配置文件

assignment 0 seconds 110 milliseconds   Time taken 2 seconds 340 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 2 seconds 340 milliseconds
assignment 0 seconds 100 milliseconds   Time taken 2 seconds 330 milliseconds
assignment 0 seconds 100 milliseconds   Time taken 2 seconds 340 milliseconds
assignment 0 seconds 100 milliseconds   Time taken 2 seconds 330 milliseconds
assignment 0 seconds 100 milliseconds   Time taken 2 seconds 340 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 2 seconds 340 milliseconds
assignment 0 seconds 100 milliseconds   Time taken 2 seconds 330 milliseconds
assignment 0 seconds 100 milliseconds   Time taken 2 seconds 340 milliseconds
assignment 0 seconds 100 milliseconds   Time taken 2 seconds 330 milliseconds

assignment 0 seconds 100 milliseconds   Time taken 1 seconds 600 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 1 seconds 600 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 1 seconds 580 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 1 seconds 590 milliseconds
assignment 0 seconds 80 milliseconds    Time taken 1 seconds 590 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 1 seconds 590 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 1 seconds 600 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 1 seconds 590 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 1 seconds 600 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 1 seconds 580 milliseconds

使用qsort发布概要文件

assignment 0 seconds 110 milliseconds   Time taken 2 seconds 340 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 2 seconds 340 milliseconds
assignment 0 seconds 100 milliseconds   Time taken 2 seconds 330 milliseconds
assignment 0 seconds 100 milliseconds   Time taken 2 seconds 340 milliseconds
assignment 0 seconds 100 milliseconds   Time taken 2 seconds 330 milliseconds
assignment 0 seconds 100 milliseconds   Time taken 2 seconds 340 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 2 seconds 340 milliseconds
assignment 0 seconds 100 milliseconds   Time taken 2 seconds 330 milliseconds
assignment 0 seconds 100 milliseconds   Time taken 2 seconds 340 milliseconds
assignment 0 seconds 100 milliseconds   Time taken 2 seconds 330 milliseconds

assignment 0 seconds 100 milliseconds   Time taken 1 seconds 600 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 1 seconds 600 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 1 seconds 580 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 1 seconds 590 milliseconds
assignment 0 seconds 80 milliseconds    Time taken 1 seconds 590 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 1 seconds 590 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 1 seconds 600 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 1 seconds 590 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 1 seconds 600 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 1 seconds 580 milliseconds

使用std:：sort（a，a+数组大小）发布配置文件

释放从文件中读取随机数据的配置文件，并使用std:：sort（a，a+数组大小）

下面是使用的源代码。希望最小的bug：）

Java源代码 请注意，在JavaSort内部，运行代码和writeFlag需要根据您想要计时的内容进行调整。还要注意，内存分配发生在for循环中（因此测试GC，但我没有看到将分配移到循环外的任何明显差异）

publicstaticvoidjavasort（int迭代，int numberrelations）{
Random ran=新的Random（）；
数学随机（）；
int运行码=2；
布尔writeFlag=false；
对于（int j=0；j0）{
而（i

C/C++源代码

#include <iostream>
#include <vector>
#include <algorithm>
#include <fstream>

#include <cstdlib>
#include <ctime>
#include <cstdio>
#include <math.h>
#include <stdio.h>
#include <time.h>
#include <stdlib.h>

#define ARRAY_SIZE 10000000

using namespace std;

int compa(const void * elem1, const void * elem2) {
    double f = *((double*) elem1);
    double s = *((double*) elem2);
    if (f > s) return 1;
    if (f < s) return -1;
    return 0;
}

int compb (const void *a, const void *b) {
   if (*(double **)a < *(double **)b) return -1;
   if (*(double **)a > *(double **)b) return 1;
   return 0;
}

void timing_testa(int iterations) {

    clock_t start = clock(), diffa, diffb;

    int msec;
    bool writeFlag = false;
    int runCode = 1;

    for (int loopCounter = 0; loopCounter < iterations; loopCounter++) {
        double *a = (double *) malloc(sizeof (double)*ARRAY_SIZE);
        start = clock();
        size_t bytes = sizeof (double)*ARRAY_SIZE;
        if (runCode == 0) {
            for (int i = 0; i < ARRAY_SIZE; i++) {
                a[i] = rand() / (RAND_MAX + 1.0);
            }
        }
        else if (runCode == 1) {
            ifstream inlezen;

            inlezen.open("test", ios::in | ios::binary);


            inlezen.read(reinterpret_cast<char*> (&a[0]), bytes);

        }
        if (writeFlag) {
            ofstream outf;
            const char* pointer = reinterpret_cast<const char*>(&a[0]);
            outf.open("test", ios::out | ios::binary);
            outf.write(pointer, bytes);
            outf.close();

        }

        diffa = clock() - start;
        msec = diffa * 1000 / CLOCKS_PER_SEC;
        printf("assignment %d seconds %d milliseconds\t", msec / 1000, msec % 1000);
        start = clock();
        //qsort(a, ARRAY_SIZE, sizeof (double), compa);
        std::sort( a, a + ARRAY_SIZE );
        //printf("%f %f %f\n",a[0],a[1000],a[ARRAY_SIZE-1]);
        diffb = clock() - start;

        msec = diffb * 1000 / CLOCKS_PER_SEC;
        printf("Time taken %d seconds %d milliseconds\n", msec / 1000, msec % 1000);
        free(a);
    }



}

/*
 * 
 */
int main(int argc, char** argv) {

    printf("hello world\n");
    double *a = (double *) malloc(sizeof (double)*ARRAY_SIZE);


    //srand(1);//change seed to fix it
    srand(time(NULL));

    timing_testa(5);



    free(a);
    return 0;
}

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#定义数组大小10000000
使用名称空间std；
内部比较（常数无效*元素1，常数无效*元素2）{
双f=*（（双*）elem1）；
双s=*（（双*）elem2）；
如果（f>s）返回1；
如果（f*（双**）b）返回1；
返回0；
}
无效定时测试（整数迭代）{
clock_t start=clock（），diffa，diffb；
整数毫秒；
bool writeFlag=false；
int运行码=1；
对于（int loopCounter=0；loopCounter

好吧，没有一个简单的方法来回答这个问题；它必须在上下文中回答

您的应用程序（中间层）是否与数据库在同一节点上运行

如果是，您不必担心数据库和中间层之间的延迟

assignment 0 seconds 100 milliseconds   Time taken 1 seconds 600 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 1 seconds 600 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 1 seconds 580 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 1 seconds 590 milliseconds
assignment 0 seconds 80 milliseconds    Time taken 1 seconds 590 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 1 seconds 590 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 1 seconds 600 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 1 seconds 590 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 1 seconds 600 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 1 seconds 580 milliseconds

assignment 0 seconds 100 milliseconds   Time taken 0 seconds 880 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 0 seconds 870 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 0 seconds 890 milliseconds
assignment 0 seconds 120 milliseconds   Time taken 0 seconds 890 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 0 seconds 890 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 0 seconds 880 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 0 seconds 900 milliseconds
assignment 0 seconds 90 milliseconds    Time taken 0 seconds 890 milliseconds
assignment 0 seconds 100 milliseconds   Time taken 0 seconds 890 milliseconds
assignment 0 seconds 150 milliseconds   Time taken 0 seconds 870 milliseconds

assignment 0 seconds 50 milliseconds    Time taken 0 seconds 880 milliseconds
assignment 0 seconds 40 milliseconds    Time taken 0 seconds 880 milliseconds
assignment 0 seconds 50 milliseconds    Time taken 0 seconds 880 milliseconds
assignment 0 seconds 50 milliseconds    Time taken 0 seconds 880 milliseconds
assignment 0 seconds 40 milliseconds    Time taken 0 seconds 880 milliseconds

public static void JavaSort(int iterations, int numberElements) {

    Random ran = new Random();
    Math.random();
    int runCode = 2;
    boolean writeFlag = false;
    for (int j = 0; j < iterations; j++) {
        double[] a1 = new double[numberElements];
        long timea = System.currentTimeMillis();
        if (runCode == 0) {
            for (int i = 0; i < numberElements; i++) {
                a1[i] = ran.nextDouble();

            }
        }            
        else if (runCode == 1) {

            //do disk io!!
            try {
            DataInputStream in = new DataInputStream(new FileInputStream("MyBinaryFile.txt"));
            int i = 0;
            //while (in.available() > 0) {
            while (i < numberElements) { //this should be changed so that I always read in the size of array elements
                a1[i++] = in.readDouble();
            }
            }
            catch (Exception e) {

            }

        }
        else if (runCode == 2) {
            try  {
                FileInputStream stream = new FileInputStream("MyBinaryFile.txt");
                FileChannel inChannel = stream.getChannel();

                ByteBuffer buffer = inChannel.map(FileChannel.MapMode.READ_ONLY, 0, inChannel.size());
                //int[] result = new int[500000];

                buffer.order(ByteOrder.BIG_ENDIAN);
                DoubleBuffer doubleBuffer = buffer.asDoubleBuffer();
                doubleBuffer.get(a1);
            }
            catch (Exception e) {

            }
        }

        if (writeFlag) {
            try {
                DataOutputStream out = new DataOutputStream(new FileOutputStream("MyBinaryFile.txt"));
                for (int i = 0; i < numberElements; i++) {
                    out.writeDouble(a1[i]);
                }
            } catch (Exception e) {

            }
        }
        long timeb = System.currentTimeMillis();
        Arrays.sort(a1);

        long timec = System.currentTimeMillis();
        System.out.println("assignment time " + (timeb - timea) + " " + " sort time " + (timec - timeb));
        //delete a1;
    }
}

#include <iostream>
#include <vector>
#include <algorithm>
#include <fstream>

#include <cstdlib>
#include <ctime>
#include <cstdio>
#include <math.h>
#include <stdio.h>
#include <time.h>
#include <stdlib.h>

#define ARRAY_SIZE 10000000

using namespace std;

int compa(const void * elem1, const void * elem2) {
    double f = *((double*) elem1);
    double s = *((double*) elem2);
    if (f > s) return 1;
    if (f < s) return -1;
    return 0;
}

int compb (const void *a, const void *b) {
   if (*(double **)a < *(double **)b) return -1;
   if (*(double **)a > *(double **)b) return 1;
   return 0;
}

void timing_testa(int iterations) {

    clock_t start = clock(), diffa, diffb;

    int msec;
    bool writeFlag = false;
    int runCode = 1;

    for (int loopCounter = 0; loopCounter < iterations; loopCounter++) {
        double *a = (double *) malloc(sizeof (double)*ARRAY_SIZE);
        start = clock();
        size_t bytes = sizeof (double)*ARRAY_SIZE;
        if (runCode == 0) {
            for (int i = 0; i < ARRAY_SIZE; i++) {
                a[i] = rand() / (RAND_MAX + 1.0);
            }
        }
        else if (runCode == 1) {
            ifstream inlezen;

            inlezen.open("test", ios::in | ios::binary);


            inlezen.read(reinterpret_cast<char*> (&a[0]), bytes);

        }
        if (writeFlag) {
            ofstream outf;
            const char* pointer = reinterpret_cast<const char*>(&a[0]);
            outf.open("test", ios::out | ios::binary);
            outf.write(pointer, bytes);
            outf.close();

        }

        diffa = clock() - start;
        msec = diffa * 1000 / CLOCKS_PER_SEC;
        printf("assignment %d seconds %d milliseconds\t", msec / 1000, msec % 1000);
        start = clock();
        //qsort(a, ARRAY_SIZE, sizeof (double), compa);
        std::sort( a, a + ARRAY_SIZE );
        //printf("%f %f %f\n",a[0],a[1000],a[ARRAY_SIZE-1]);
        diffb = clock() - start;

        msec = diffb * 1000 / CLOCKS_PER_SEC;
        printf("Time taken %d seconds %d milliseconds\n", msec / 1000, msec % 1000);
        free(a);
    }



}

/*
 * 
 */
int main(int argc, char** argv) {

    printf("hello world\n");
    double *a = (double *) malloc(sizeof (double)*ARRAY_SIZE);


    //srand(1);//change seed to fix it
    srand(time(NULL));

    timing_testa(5);



    free(a);
    return 0;
}