OCI编程高级篇（二十二） OCI多线程编程和示例代码

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 在前面我们介绍连接池时，用了单线程编写了一个实例，这不能体现出连接池的优势，连接池更应该用在多线程的环境中。我们介绍了多线程的函数后，今天就用多线程改写一下原来的例子。

还是先创建连接池，然后创建并启动4个线程，每个线程赋值一个数字，然后通过数据库的dual来取得数字，打印出来，用dual来取数目的是为了使用连接池的会话。示例代码如下。

 

#include "stdio.h"
#include "stdlib.h"
#include "stdint.h"
#include "memory.h"
#include "string.h"
#include "time.h"
#include "errno.h"
#include "oci.h"

/* 定义全局变量 */
OCIEnv          *envhp  = NULL;         /* OCI环境句柄 */
OCIError        *errhp  = NULL;         /* 错误句柄 */
OCICPool        *poolhp = NULL;         /* 连接池句柄 */

sb4             pool_name_len;          /* 连接池名称长度 */
char            *pool_name = NULL;      /* 连接池名称 */


struct {
    char        uname[32];              /* 认证用户名 */
    char        upwd[32];               /* 认证用户密码 */
} inputs;

/* 打印使用说明 */
static void usage(const char *prg){
    fprintf(stderr,
        "Usage: %s user/password\n\n"
        "  user      oracle user\n"
        "  password  user password\n"
        , prg
    );
}
/* 解析命令行参数 */
static int parse_inputs(int argc, char *argv[]){
    char        *p;

    if (argc < 2) {
      usage(argv[0]);
      return (-1);
    }

    if ((p=strchr(argv[1], '/')) == NULL) {
      usage(argv[0]);
      return (-1);
    }

    *p++ = '\0';
    memset(&inputs, 0, sizeof(inputs));
    strncpy(inputs.uname, argv[1], 31);
    strncpy(inputs.upwd, p, 31);

    return (0);
}
static char ora_env[][16] =
{
  "ORACLE_HOME",
  "ORACLE_SID",
  ""
};
/* 检查程序运行的Oracle环境变量 */
static int check_ora_env(void){
    int         i;

    for (i=0; ora_env[i][0]; i++) {
        if (getenv(ora_env[i]) == NULL) {
            fprintf(stderr, "env %s not set.\n", ora_env[i]);
            return (-1);
        }
    }

    return (0);
}
/* 创建连接池函数 */
static int create_connection_pool(void){
    sword       rc;
    sb4         ec;
    ub4         conn_min;
    ub4         conn_max;
    ub4         conn_inc;
    OraText     errbuf[512];


    /* 创建OCI环境变量，要使用OCI_THREADED模式 */
    rc = OCIEnvCreate(
        &envhp,                 /* envhpp */
        OCI_THREADED,           /* mode */
        (void *)NULL,           /* ctxp */
        NULL,
        NULL,
        NULL,
        (size_t)0,
        (void **)NULL
    );

    if (rc != OCI_SUCCESS) {
        fprintf(stderr, "OCIEnvCreate() - allocate OCI env handle error !\n");
        return (-1);
    }

    /* 分配错误句柄 */
    rc = OCIHandleAlloc(
        (void *)envhp,
        (void **)&errhp,
        OCI_HTYPE_ERROR,
        0,
        (void **)NULL
    );

    if (rc != OCI_SUCCESS) {
        fprintf(stderr, "OCIHandleAlloc() - allocate OCI error handle error !\n");
        return (-1);
    }

    /* 分配连接池句柄 */
    rc = OCIHandleAlloc(
        (void *)envhp,
        (void **)&poolhp,
        OCI_HTYPE_CPOOL,
        (size_t)0,
        (void **)NULL
    );

    if (rc != OCI_SUCCESS) {
        fprintf(stderr, "OCIHandleAlloc() - allocate connection pool handle error !\n");
        return (-1);
    }

    /* 创建连接池 */
    conn_min = 3;
    conn_max = 5;
    conn_inc = 1;
    rc = OCIConnectionPoolCreate(
        envhp, errhp, poolhp,
        (OraText **)&pool_name, &pool_name_len,
        (const OraText *)"", 0,
        (ub4)conn_min, (ub4)conn_max, (ub4)conn_inc,
        (OraText *)inputs.uname, strlen(inputs.uname),
        (OraText *)inputs.upwd, strlen(inputs.upwd),
        OCI_DEFAULT
    );

    if (rc != OCI_SUCCESS) {
        OCIErrorGet(errhp, 1, NULL, &ec, errbuf, 512, OCI_HTYPE_ERROR);
        fprintf(stderr, "OCIConnectionPoolCreate() - [%d] %s\n", ec, errbuf);
        return (-1);
    }

    return (0);
}
/* 销毁连接池函数 */
static int destroy_connection_pool(void){
    sword       rc;
    sb4         ec;
    OraText     errbuf[512];


    /* 销毁连接池 */
    if (poolhp != NULL) {
        rc = OCIConnectionPoolDestroy(poolhp, errhp, OCI_DEFAULT);

        if (rc != OCI_SUCCESS) {
            OCIErrorGet(errhp, 1, NULL, &ec, errbuf, 512, OCI_HTYPE_ERROR);
            fprintf(stderr, "OCIConnectionPoolDestroy() - [%d] %s\n", ec, errbuf);
            return (-1);
        }

        /* 释放连接池句柄 */
        rc = OCIHandleFree((void *)poolhp, OCI_HTYPE_CPOOL);

        if (rc != OCI_SUCCESS) {
            fprintf(stderr, "OCIHandleFree() - free connection pool handle error !\n");
            return (-1);
        }
    }

    /* 释放错误句柄 */
    if (errhp != NULL) {
        rc = OCIHandleFree(
            errhp,
            OCI_HTYPE_ERROR
        );

        if (rc != OCI_SUCCESS) {
            fprintf(stderr, "OCIHandleFree() - free error handle error !\n");
            return (-1);
        }
    }

    /* 释放OCI环境句柄 */
    if (envhp != NULL) {
        rc = OCIHandleFree(
            envhp,
            OCI_HTYPE_ENV
        );

        if (rc != OCI_SUCCESS) {
            fprintf(stderr, "OCIHandleFree() - free env handle error !\n");
            return (-1);
        }
    }

    return (0);
}
/* 线程开始运行入口函数 */
static void thread_run(void *arg){
    sword       rc;
    sb4         ec;
    int         num;
    int         slen;
    ub4         u4;
    OCIError    *errhp1 = NULL;
    OCISvcCtx   *svchp1 = NULL;
    OCIStmt     *stmthp = NULL;
    OCIDefine   *defp;
    char        sqltxt[1024];
    OraText     errbuf[512];


    /* 创建本线程使用的错误句柄 */
    rc = OCIHandleAlloc(
        (void *)envhp,
        (void **)&errhp1,
        OCI_HTYPE_ERROR,
        0,
        (void **)NULL
    );

    if (rc != OCI_SUCCESS) {
        fprintf(stderr, "OCIHandleAlloc() - allocate error handle error !\n");
        return;
    }

    /* 获取会话，使用了OCILogon2()函数 */
    rc = OCILogon2(envhp, errhp1, &svchp1,
        (const OraText *)inputs.uname, (ub4)strlen(inputs.uname),
        (const OraText *)inputs.upwd,  (ub4)strlen(inputs.upwd),
        (const OraText *)pool_name,    (ub4)pool_name_len,
        OCI_CPOOL
    );

    if (rc != OCI_SUCCESS) {
        OCIErrorGet(errhp1, 1, NULL, &ec, errbuf, 512, OCI_HTYPE_ERROR);
        fprintf(stderr, "OCILogon2() - [%d] %s\n", ec, errbuf);
        goto thread_error;
    }

    /* 分配语句句柄 */
    rc = OCIHandleAlloc(
        (void *)envhp,
        (void **)&stmthp,
        OCI_HTYPE_STMT,
        0,
        (void **)NULL
    );

    if (rc != OCI_SUCCESS) {
        fprintf(stderr, "OCIHandleAlloc() - allocate statement handle error !\n");
        goto thread_error;
    }

    /* 得到线程传入的参数 */
    num = *((int *)arg);

    /* 使用会话从dual中获取这个数字 */
    sprintf(sqltxt, "select %d from dual", num);
    slen = strlen(sqltxt);

    /* 准备语句 */
    rc = OCIStmtPrepare(stmthp, errhp1, (const OraText *)sqltxt, slen,
          OCI_NTV_SYNTAX, OCI_DEFAULT);

    if (rc != OCI_SUCCESS) {
        OCIErrorGet(errhp1, 1, NULL, &ec, errbuf, 512, OCI_HTYPE_ERROR);
        fprintf(stderr, "OCIStmtPrepare() - [%d] %s\n", ec, errbuf);
        goto thread_error;
    }

    /* 定义输出变量 */
    rc = OCIDefineByPos(stmthp,
        &defp,
        errhp1,
        (ub4)1,
        (void *)&u4,
        (sb4)4,
        (ub2)SQLT_INT,
        (void *)NULL,
        (ub2 *)NULL,
        (ub2 *)NULL,
        (ub4)OCI_DEFAULT
    );

    if (rc != OCI_SUCCESS) {
        OCIErrorGet(errhp1, 1, NULL, &ec, errbuf, 512, OCI_HTYPE_ERROR);
        fprintf(stderr, "OCIDefineByPos() - [%d] %s\n", ec, errbuf);
        goto thread_error;
    }

    /* 执行查询语句 */
    rc = OCIStmtExecute(svchp1, stmthp, errhp1, 0, 0, NULL, NULL, OCI_DEFAULT);

    if (rc != OCI_SUCCESS) {
        OCIErrorGet(errhp1, 1, NULL, &ec, errbuf, 512, OCI_HTYPE_ERROR);
        fprintf(stderr, "OCIStmtExecute() - [%d] %s\n", ec, errbuf);
        goto thread_error;
    }

    /* 获取结果集 */
    rc = OCIStmtFetch2(stmthp, errhp1, 1, OCI_FETCH_NEXT, 0, OCI_DEFAULT);

    if (rc != OCI_SUCCESS) {
        OCIErrorGet(errhp1, 1, NULL, &ec, errbuf, 512, OCI_HTYPE_ERROR);
        fprintf(stderr, "OCIStmtFetch2() - [%d] %s\n", ec, errbuf);
        goto thread_error;
    }

    /* 打印取到的数字 */
    fprintf(stdout, "number from dual is: %d\n", u4);

    /* 释放语句句柄 */
    rc = OCIHandleFree(
        stmthp,
        OCI_HTYPE_STMT
    );

    if (rc != OCI_SUCCESS) {
        fprintf(stderr, "OCIHandleFree() - free statement handle error !\n");
        goto thread_error;
    }

    stmthp = NULL;

    /* 退出会话 */
    rc = OCILogoff(svchp1, errhp1);

    if (rc != OCI_SUCCESS) {
        OCIErrorGet(errhp1, 1, NULL, &ec, errbuf, 512, OCI_HTYPE_ERROR);
        fprintf(stderr, "OCILogoff() - [%d] %s\n", ec, errbuf);
        goto thread_error;
    }

    svchp1 = NULL;

    /* 释放错误句柄 */
    rc = OCIHandleFree(
        errhp1,
        OCI_HTYPE_ERROR
    );

    if (rc != OCI_SUCCESS) {
        fprintf(stderr, "OCIHandleFree() - free error handle error !\n");
    }

    errhp1 = NULL;

    return;

thread_error:
    if (stmthp != NULL) {
        OCIHandleFree(stmthp, OCI_HTYPE_STMT);
    }

    if (svchp1 != NULL) {
        OCILogoff(svchp1, errhp1);
    }

    if (errhp1 != NULL) {
        OCIHandleFree(errhp1, OCI_HTYPE_ERROR);
    }
}
/* 定义线程的最大个数，和传入线程的数字数组 */
#define MAX_THREAD      4
int     t_num[MAX_THREAD];
int main(int argc, char **argv){
    int                 i;
    sword               rc;
    sb4                 ec;
    OCIThreadId         *tid[MAX_THREAD];
    OCIThreadHandle     *thp[MAX_THREAD];
    OraText             errbuf[512];


    /* 解析命令行参数 */
    if (parse_inputs(argc, argv) < 0)
        return (-1);

    /* 检查OCI程序运行的环境变量 */
    if (check_ora_env() < 0)
        return (-1);

    /* 创建连接池 */
    if (create_connection_pool() < 0)
        goto error_exit;

    /* 初始化OCI线程包 */
    OCIThreadProcessInit();

    /* 初始化线程包上下文 */
    rc = OCIThreadInit(envhp, errhp);

    if (rc != OCI_SUCCESS) {
        OCIErrorGet(errhp, 1, NULL, &ec, errbuf, 512, OCI_HTYPE_ERROR);
        fprintf(stderr, "OCIThreadInit() - [%d] %s\n", ec, errbuf);
    }

    /* 初始化每个线程的ID和句柄 */
    for (i=0; i<MAX_THREAD; i++) {
        rc = OCIThreadIdInit(envhp, errhp, &tid[i]);
        if (rc != OCI_SUCCESS) {
            OCIErrorGet(errhp, 1, NULL, &ec, errbuf, 512, OCI_HTYPE_ERROR);
            fprintf(stderr, "OCIThreadIdInit() - [%d] %s\n", ec, errbuf);
        }

        rc = OCIThreadHndInit(envhp, errhp, &thp[i]);
        if (rc != OCI_SUCCESS) {
            OCIErrorGet(errhp, 1, NULL, &ec, errbuf, 512, OCI_HTYPE_ERROR);
            fprintf(stderr, "OCIThreadHndInit() - [%d] %s\n", ec, errbuf);
        }
    }

    /* 创建和启动每个线程，传入参数 */
    for (i=0; i<MAX_THREAD; i++) {
        t_num[i] = i+1;

        rc = OCIThreadCreate(envhp, errhp, thread_run,
            (void *)&t_num[i], tid[i], thp[i]);
        if (rc != OCI_SUCCESS) {
            OCIErrorGet(errhp, 1, NULL, &ec, errbuf, 512, OCI_HTYPE_ERROR);
            fprintf(stderr, "OCIThreadCreate() - [%d] %s\n", ec, errbuf);
        }
    }

    for (i=0; i<MAX_THREAD; i++) {
        /* 等待线程结束 */
        rc = OCIThreadJoin(envhp, errhp, thp[i]);
        if (rc != OCI_SUCCESS) {
            OCIErrorGet(errhp, 1, NULL, &ec, errbuf, 512, OCI_HTYPE_ERROR);
            fprintf(stderr, "OCIThreadJoin() - [%d] %s\n", ec, errbuf);
        }

        /* 关闭线程句柄 */
        rc = OCIThreadClose(envhp, errhp, thp[i]);
        if (rc != OCI_SUCCESS) {
            OCIErrorGet(errhp, 1, NULL, &ec, errbuf, 512, OCI_HTYPE_ERROR);
            fprintf(stderr, "OCIThreadClose() - [%d] %s\n", ec, errbuf);
        }

        /* 销毁线程ID */
        rc = OCIThreadIdDestroy(envhp, errhp, &tid[i]);
        if (rc != OCI_SUCCESS) {
            OCIErrorGet(errhp, 1, NULL, &ec, errbuf, 512, OCI_HTYPE_ERROR);
            fprintf(stderr, "OCIThreadIdDestroy() - [%d] %s\n", ec, errbuf);
        }

        /* 销毁线程句柄 */
        rc = OCIThreadHndDestroy(envhp, errhp, &thp[i]);
        if (rc != OCI_SUCCESS) {
            OCIErrorGet(errhp, 1, NULL, &ec, errbuf, 512, OCI_HTYPE_ERROR);
            fprintf(stderr, "OCIThreadHndDestroy() - [%d] %s\n", ec, errbuf);
        }
    }

    /* 结束线程包 */
    rc = OCIThreadTerm(envhp, errhp);

    if (rc != OCI_SUCCESS) {
        OCIErrorGet(errhp, 1, NULL, &ec, errbuf, 512, OCI_HTYPE_ERROR);
        fprintf(stderr, "OCIThreadTerm() - [%d] %s\n", ec, errbuf);
    }

    /* 销毁连接池 */
    destroy_connection_pool();

    return (0);

error_exit:
    destroy_connection_pool();
    return (-1);
}