mysql 簡單的連接池實現

一個mysql客戶端項目中，所有的參數都保存到mysql中，需要頻繁的訪問mysql server，其實使用一個mysql長連接也可以滿足要求，但為了更好的利用多核CPU嘗試使用連接池來充分發揮多線程的優勢(電腦配置 i7-4核8線程)。

下面是mysql_pool實現的源碼，

1. 頭文件 mysql_pool.h

// 
// 創建人： levy
// 創建時間：Jun 5, 2017
// 功能：mysql_pool.h
// Copyright (c) 2017 levy. All Rights Reserved.
// Ver          變更日期        負責人                           變更內容
// ──────────────────────────────────────────────────────────────────────────
// V0.01         Jun 5, 2017                  levy          初版
// 


#ifndef MYSQL_POOL_H_
#define MYSQL_POOL_H_
#include <mysql.h>
#include <pthread.h>
#define MAX_KEPP_CONNECTIONS 8
typedef struct mysql_conn        //mysql連接鏈表結構體定義
{
    struct mysql_conn * next;
    struct mysql_conn * prev;
    MYSQL conn;

}mysql_conn;

typedef struct mysql_pool        //mysql連接池結構體定義
{
    char host[64];                //主機名稱
    char username[32];            //用戶名
    char passwd[32];            //密碼
    char database[32];            //默認數據庫
    int s_port;                    //端口號，默認3306
    int max_connections;        //保持開啟的mysql最大連接數
    int free_connections;        //當前空閑的mysql連接數
    int is_idle_block;            //是否開啟了無可用連接阻塞
    pthread_mutex_t lock;        //mysql鏈表鎖
    pthread_cond_t idle_signal;    //等待可用連接的條件變量
    mysql_conn * mysql_list;    //mysql連接池鏈表
}mysql_pool;

void mysql_pool_init();
void destory_mysql_pool();
void destory_mysql_connection(mysql_conn *conn);
void release_mysql_connection(mysql_conn *conn);
mysql_conn * get_mysql_connection();

MYSQL_RES* mysql_execute_query(const char *sql,unsigned long length,int *flag);

#endif /* MYSQL_POOL_H_ */

2.連接池實現  1 //

// 創建人： levy
// 創建時間：Jun 5, 2017
// 功能：mysql_pool.c
// Copyright (c) 2016 levy. All Rights Reserved.
// Ver          變更日期        負責人                           變更內容
// ──────────────────────────────────────────────────────────────────────────
// V0.01         Jun 5, 2017                  levy          初版
// 

#include "mysql_pool.h"
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
static mysql_pool pool_mysql;//連接池定義
unsigned int query_times = 0;//mysql所有的查詢次數，用於測試

/*創建一個新的mysql連接
 * @return NULL代表創建失敗。
 */
mysql_conn * mysql_new_connection()
{
    mysql_conn * conn=malloc(sizeof(mysql_conn));
    if(mysql_init(&conn->conn)==NULL)
    {
        printf("can not init mysql: [%s]\n",strerror(errno));
        free(conn);
        return NULL;
    }
    if(mysql_options(&conn->conn, MYSQL_SET_CHARSET_NAME, "UTF8")!=0)
    {
        printf("can not set mysql options[errno = %d]: [%s]\n",mysql_errno(&conn->conn),mysql_error(&conn->conn));
        free(conn);
        return NULL;
    }
    //連接到mysql服務端，設置CLIENT_MULTI_STATEMENTS通知服務器客戶端可以處理由多語句或者存儲過程執行生成的多結果集
    if(mysql_real_connect(&conn->conn,pool_mysql.host,pool_mysql.username,pool_mysql.passwd,pool_mysql.database,pool_mysql.s_port,NULL, CLIENT_MULTI_STATEMENTS)==NULL)
    {
        printf("can not connect  mysql server[errno = %d]: [%s]\n",mysql_errno(&conn->conn),mysql_error(&conn->conn));
        free(conn);
        return NULL;
    }
    conn->next = NULL;
    conn->prev = NULL;
    return conn;
}

/*向鏈接池中壓入一個mysql連接conn
 * */
void conn_push(mysql_conn * conn)
{
    mysql_conn *lc = pool_mysql.mysql_list;
    if(lc==NULL)
    {
        pool_mysql.mysql_list=conn;

    }else
    {
        while(lc->next)
        {
            lc=lc->next;
        }
        lc->next = conn;
        conn->prev = lc;

    }
    pool_mysql.free_connections++;
}

/*從連接池中出棧一個mysql連接
 * @return NULL表示連接池中沒有可用的連接
 * */
mysql_conn * conn_pop()
{
    mysql_conn*conn = pool_mysql.mysql_list;
    if(conn != NULL)
    {

        pool_mysql.mysql_list = conn->next;
        if(pool_mysql.mysql_list)
        {
            pool_mysql.mysql_list->prev = NULL;
        }
        pool_mysql.free_connections--;
    }
    return conn;
}

/*初始化mysql連接池*/
void mysql_pool_init()
{
    mysql_conn * conn;
    strncpy(pool_mysql.host,"localhost",sizeof(pool_mysql.host));
    strncpy(pool_mysql.username,"test",sizeof(pool_mysql.username));
    strncpy(pool_mysql.passwd,"test",sizeof(pool_mysql.passwd));
    strncpy(pool_mysql.database,"test",sizeof(pool_mysql.database));
    pool_mysql.s_port = 3306;
    pool_mysql.max_connections=MAX_KEEP_CONNECTIONS;
    pool_mysql.free_connections = 0;
    pool_mysql.mysql_list = NULL;
    pool_mysql.is_idle_block = 0;
    pthread_mutex_init(&pool_mysql.lock,NULL);
    pthread_cond_init(&pool_mysql.idle_signal,NULL);
    pthread_mutex_lock(&pool_mysql.lock);
    for(int i=0;i<pool_mysql.max_connections;i++)
    {
        conn=mysql_new_connection();
        if(conn)
        {
            conn_push(conn);
        }else
        {

        }

    }
    pthread_mutex_unlock(&pool_mysql.lock);
}

/*從連接池中獲取一個mysql連接*/
mysql_conn * get_mysql_connection()
{
    pthread_mutex_lock(&pool_mysql.lock);
    mysql_conn *conn = conn_pop();
    pthread_mutex_unlock(&pool_mysql.lock);
    return conn;
}

/*從連接池中獲取一個mysql連接，如果連接池為空，測阻塞*/
mysql_conn * get_mysql_connection_block()
{
    pthread_mutex_lock(&pool_mysql.lock);
    mysql_conn *conn = conn_pop();
    while(conn == NULL)
    {
        pool_mysql.is_idle_block ++;
        pthread_cond_wait(&pool_mysql.idle_signal,&pool_mysql.lock);
        conn = conn_pop();
        pool_mysql.is_idle_block --;
    }
    query_times++;
    pthread_mutex_unlock(&pool_mysql.lock);
    return conn;
}


/*回收一個mysql連接到連接池*/
void release_mysql_connection(mysql_conn *conn)
{
    pthread_mutex_lock(&pool_mysql.lock);
    conn->next = NULL;
    conn->prev = NULL;
    conn_push(conn);
    if(pool_mysql.is_idle_block)
    {
        pthread_cond_signal(&pool_mysql.idle_signal);
    }
    pthread_mutex_unlock(&pool_mysql.lock);
}

/*銷毀一個mysql連接，並釋放其占用的資源*/
void destory_mysql_connection(mysql_conn *conn)
{
    mysql_close(&conn->conn);
    free(conn);
}

//銷毀連接池中的所有連接
void destory_mysql_pool()
{
    mysql_conn *conn;
    pthread_mutex_lock(&pool_mysql.lock);
    conn = conn_pop();
    for(;conn;conn = conn_pop())
    {
        destory_mysql_connection(conn);
    }
    pthread_mutex_unlock(&pool_mysql.lock);
}


MYSQL_RES* mysql_execute_query(const char *sql,unsigned long length,int *flag)
{
    int res;
    MYSQL_RES *res_ptr;
    mysql_conn*con = get_mysql_connection_block();
    if(con == NULL)
    {
        printf("can not get mysql connections from the pools\n");
        *flag =-2;
        return NULL;
    }
    *flag=0;
    res=mysql_real_query(&con->conn,sql,length);
    if(res!=0)
    {
        printf("mysql_real_query error [errno = %d]: [%s]\n",mysql_errno(&con->conn),mysql_error(&con->conn));
        release_mysql_connection(con);
        *flag=res;
        return NULL;
    }
    res_ptr = mysql_store_result(&con->conn);
    if(res_ptr == NULL)
    {
        printf("mysql_store_result error [errno = %d]: [%s]\n",mysql_errno(&con->conn),mysql_error(&con->conn));
    }
    release_mysql_connection(con);
    return res_ptr;
}
3.測試主函數main.c，同時創建10000個線程 1  2 // 創建人： levy

// 創建時間：May 25, 2017  4 // 功能：main.c  5 // Copyright (c) 2016 levy. All Rights Reserved.  6 // Ver 變更日期 負責人 變更內容  7 // ──────────────────────────────────────────────────────────────────────────  8 // V0.01 May 25, 2017 levy 初版  9 // 10 11 #include <stdlib.h> 12 #include <stdio.h> 13 #include <unistd.h> 14 #include <time.h> 15 #include <sys/time.h> 16 #include <pthread.h> 17 #include <string.h> 18 #include <errno.h> 19 #include "mysql_pool.h" 20 21 const char *test_sql = "SELECT ID,Name,Value,RecordTime FROM test where ID <1024"; 22 extern unsigned int query_times ; 23 24 25 void * test_thread(void *arp) 26 { 27 int flag=0; 28 int count=0; 29 MYSQL_RES * resptr; 30 //for(int i=0;i<10;i++) 31  { 32 resptr=mysql_execute_query(test_sql,strlen(test_sql),&flag); 33 if(resptr) 34  { 35 count++; 36  mysql_free_result(resptr); 37 }else 38  { 39 perror("error"); 40  } 41  } 42 //printf("I has finsh %d query.\n",count); 43  pthread_exit(NULL); 44 } 45 46 47 48 #define thread_nums 10000 49 int main(void ) 50 { 51  mysql_pool_init(); 52  pthread_t th[thread_nums]; 53 struct timeval tnow,tnow1,tnow2; 54 gettimeofday(&tnow1, NULL); 55 printf("start time tv_sec = %ld,tv_usec = %ld \n",tnow1.tv_sec,tnow1.tv_usec); 56 for(int i=0;i<thread_nums;i++) 57  { 58 pthread_create(&th[i],NULL,test_thread,NULL); 59  } 60 for(int i=0;i<thread_nums;i++) 61  { 62  pthread_join(th[i],NULL); 63  } 64 gettimeofday(&tnow2, NULL); 65 timersub(&tnow2,&tnow1,&tnow); 66 printf("Max keep connections = %d,max_thread_nums=%d,total query times=%d,use %ld ms",MAX_KEPP_CONNECTIONS,thread_nums,query_times,tnow.tv_sec*1000+tnow.tv_usec/1000);

    //printf("total time tv_sec = %ld.%3ld s \n",);
 destory_mysql_pool(); 69  pthread_exit(NULL); 70 }

 

測試結果

1.Max keep connections = 1,max_thread_nums=10000,total query times=10000,use 6114 ms

2.Max keep connections = 2,max_thread_nums=10000,total query times=10000,use 3404 ms

3.Max keep connections = 4,max_thread_nums=10000,total query times=10000,use 1958 ms

4.Max keep connections = 8,max_thread_nums=10000,total query times=10000,use 1794 ms

5.Max keep connections = 16,max_thread_nums=10000,total query times=10000,use 1787 ms

 總結：從測試結果可以看出保持最大連接數目為cpu的核心數能夠充分發揮cpu多核的優勢。

編輯日期：2017-06-05 16:55:39