Code::Blocks执行MySQL循环插入C++程序时返回0xC0000005错误的解决

问题描述 #

我是C++新手，正在开发需持续向数据库插入数据的程序，使用XAMPP搭建数据库，希望在函数内实现插入循环。运行程序时能插入部分数据，但几秒后程序终止，返回错误码-10737741819(0xC0000005)，构建日志显示进程终止状态为-1073741510。

原代码：

#include "stdio.h"
#include "fstream"
#include "iostream"
#include "mysql.h"
#include "sstream"

void loop();
void print();

int i;
const char* hostname    = "localhost";
const char* username    = "root";
const char* password    = "";
const char* database    = "testinsertdb";
unsigned int port       = 3306;
const char* unixsocket  = NULL;
unsigned long clientflag = 0;


insertion(){
    MYSQL* conn;
    conn = mysql_init(0);
    conn = mysql_real_connect(conn, hostname, username, password, database, port, unixsocket, clientflag);
    int qstate=0;
    using namespace std;
    stringstream ss;
        ss << " INSERT INTO test (number) values ('" <<i<<"')";
        string query = ss.str ();
        const char * q = query.c_str();
        qstate = mysql_query(conn, q);
         if (qstate == 0)
        {

            cout <<" Record inserted successfully ..."<<endl;
        }
        else
        {
            cout <<" Error, data not inserted..."<<endl;
        }
}

int main()
{
    print();
    return 0;
}

void print()
{
    for (int j = 0; j < 1000000; j++) {
     loop();
}
}


void loop()
{
    i=1;
    insertion();
}

解决方案 #

1. 修复核心崩溃问题 #

程序崩溃（0xC0000005为内存访问违规）的主要原因：

• 每次调用insertion()新建数据库连接但从不关闭，导致连接资源耗尽、内存泄漏
• 未检查mysql_real_connect()返回值，连接失败时conn为NULL，调用mysql_query()触发空指针访问

修复代码：复用单个数据库连接，避免重复创建/销毁：

#include "stdio.h"
#include "fstream"
#include "iostream"
#include "mysql.h"
#include "sstream"

using namespace std;

MYSQL* conn;
const char* hostname    = "localhost";
const char* username    = "root";
const char* password    = "";
const char* database    = "testinsertdb";
unsigned int port       = 3306;
const char* unixsocket  = NULL;
unsigned long clientflag = 0;

// 初始化数据库连接
bool initDB() {
    conn = mysql_init(0);
    if (!conn) {
        cout << "mysql_init failed: " << mysql_error(conn) << endl;
        return false;
    }
    conn = mysql_real_connect(conn, hostname, username, password, database, port, unixsocket, clientflag);
    if (!conn) {
        cout << "mysql_real_connect failed: " << mysql_error(conn) << endl;
        return false;
    }
    cout << "Connected to database successfully!" << endl;
    return true;
}

// 关闭数据库连接
void closeDB() {
    if (conn) {
        mysql_close(conn);
        cout << "Database connection closed." << endl;
    }
}

// 插入数据，复用已有连接
void insertion(int value) {
    if (!conn) {
        cout << "Error: No database connection!" << endl;
        return;
    }
    int qstate = 0;
    stringstream ss;
    ss << "INSERT INTO test (number) values ('" << value << "')";
    string query = ss.str();
    const char* q = query.c_str();
    qstate = mysql_query(conn, q);
    if (qstate != 0) {
        cout << "Error inserting data: " << mysql_error(conn) << endl;
    }
}

int main() {
    if (!initDB()) {
        return 1;
    }
    // 循环插入100万条自增数据
    for (int j = 1; j <= 1000000; j++) {
        insertion(j);
    }
    closeDB();
    return 0;
}

2. 优化插入效率（推荐） #

100万次单条插入效率极低，建议用以下两种方式优化：

方式A：预处理语句

避免重复解析SQL，提升效率同时防止SQL注入：

void batchInsert(int start, int count) {
    MYSQL_STMT* stmt = mysql_stmt_init(conn);
    if (!stmt) {
        cout << "mysql_stmt_init failed: " << mysql_error(conn) << endl;
        return;
    }
    const char* query = "INSERT INTO test (number) VALUES (?)";
    if (mysql_stmt_prepare(stmt, query, strlen(query)) != 0) {
        cout << "mysql_stmt_prepare failed: " << mysql_stmt_error(stmt) << endl;
        mysql_stmt_close(stmt);
        return;
    }
    MYSQL_BIND bind[1];
    memset(bind, 0, sizeof(bind));
    int value;
    bind[0].buffer_type = MYSQL_TYPE_LONG;
    bind[0].buffer = &value;
    if (mysql_stmt_bind_param(stmt, bind) != 0) {
        cout << "mysql_stmt_bind_param failed: " << mysql_stmt_error(stmt) << endl;
        mysql_stmt_close(stmt);
        return;
    }
    for (int i = start; i < start + count; i++) {
        value = i;
        if (mysql_stmt_execute(stmt) != 0) {
            cout << "Insert failed for " << i << ": " << mysql_stmt_error(stmt) << endl;
        }
    }
    mysql_stmt_close(stmt);
}

// main函数中调用分批次插入
int main() {
    if (!initDB()) {
        return 1;
    }
    int batchSize = 1000;
    for (int j = 1; j <= 1000000; j += batchSize) {
        batchInsert(j, min(batchSize, 1000000 - j + 1));
        cout << "Inserted batch: " << j << " to " << j + batchSize - 1 << endl;
    }
    closeDB();
    return 0;
}

方式B：批量SQL插入

将多条插入合并为单条SQL，减少网络交互：

void batchInsertSQL(int start, int count) {
    stringstream ss;
    ss << "INSERT INTO test (number) VALUES ";
    for (int i = start; i < start + count; i++) {
        if (i != start) ss << ", ";
        ss << "(" << i << ")";
    }
    string query = ss.str();
    if (mysql_query(conn, query.c_str()) != 0) {
        cout << "Batch insert failed: " << mysql_error(conn) << endl;
    } else {
        cout << "Batch inserted " << count << " records." << endl;
    }
}

3. 修复其他代码问题 #

• 原代码insertion()函数无返回类型，C++要求必须显式声明（如void）
• 全局变量i被强制设为1，导致插入数据重复，改为直接传递循环变量更合理
• 循环中频繁打印日志会拖慢程序，建议注释或批量打印

4. 错误码说明 #

• 0xC0000005：内存访问违规，通常由空指针访问、内存耗尽导致
• -1073741510：对应0xC000013A，表示程序被系统强制终止（多因内存占用过高）

内容的提问来源于stack exchange，提问作者anonymous