MySQL由于它本身的小巧和操作的高效, 在数据库应用中越来越多的被采用.我在开发一个P2P应用的时候曾经使用MySQL来保存P2P节点,由于P2P的应用中,结点数动辄上万个,而且节点变化频繁,因此一定要保持查询和插入的高效.以下是我在使用过程中做的提高效率的三个有效的尝试. 1、使用statement进行绑定查询 使用statement可以提前构建查询语法树,在查询时不再需要构建语法树就直接查询.因此可以很好的提高查询的效率. 这个方法适合于查询条件固定但查询非常频繁的场合. 使用方法是： 绑定, 创建一个MYSQL_STMT变量,与对应的查询字符串绑定,字符串中的问号代表要传入的变量,每个问号都必须指定一个变量. 查询, 输入每个指定的变量, 传入MYSQL_STMT变量用可用的连接句柄执行. 代码如下： //1.绑定 bool CDBManager::BindInsertStmt(MYSQL * connecthandle) { //作插入操作的绑定 MYSQL_BIND insertbind[FEILD_NUM]; if(m_stInsertParam == NULL) m_stInsertParam = new CHostCacheTable; m_stInsertStmt = mysql_stmt_init(connecthandle); //构建绑定字符串 char insertSQL[SQL_LENGTH]; strcpy(insertSQL, "insert into HostCache(SessionID, ChannelID, ISPType, " "ExternalIP, ExternalPort, InternalIP, InternalPort) " "values(?, ?, ?, ?, ?, ?, ?)"); mysql_stmt_prepare(m_stInsertStmt, insertSQL, strlen(insertSQL)); int param_count= mysql_stmt_param_count(m_stInsertStmt); if(param_count != FEILD_NUM) return false; //填充bind结构数组, m_sInsertParam是这个statement关联的结构变量 memset(insertbind, 0, sizeof(insertbind)); insertbind[0].buffer_type = MYSQL_TYPE_STRING; insertbind[0].buffer_length = ID_LENGTH /* -1 */; insertbind[0].buffer = (char *)m_stInsertParam->sessionid; insertbind[0].is_null = 0; insertbind[0].length = 0; insertbind[1].buffer_type = MYSQL_TYPE_STRING; insertbind[1].buffer_length = ID_LENGTH /* -1 */; insertbind[1].buffer = (char *)m_stInsertParam->channelid; insertbind[1].is_null = 0; insertbind[1].length = 0; insertbind[2].buffer_type = MYSQL_TYPE_TINY; insertbind[2].buffer = (char *)&m_stInsertParam->ISPtype; insertbind[2].is_null = 0; insertbind[2].length = 0; insertbind[3].buffer_type = MYSQL_TYPE_LONG; insertbind[3].buffer = (char *)&m_stInsertParam->externalIP; insertbind[3].is_null = 0; insertbind[3].length = 0; insertbind[4].buffer_type = MYSQL_TYPE_SHORT; insertbind[4].buffer = (char *)&m_stInsertParam->externalPort; insertbind[4].is_null = 0; insertbind[4].length = 0; insertbind[5].buffer_type = MYSQL_TYPE_LONG; insertbind[5].buffer = (char *)&m_stInsertParam->internalIP; insertbind[5].is_null = 0; insertbind[5].length = 0; insertbind[6].buffer_type = MYSQL_TYPE_SHORT; insertbind[6].buffer = (char *)&m_stInsertParam->internalPort; insertbind[6].is_null = 0; insertbind[6].is_null = 0; //绑定 if (mysql_stmt_bind_param(m_stInsertStmt, insertbind)) return false; return true; } //2.查询 bool CDBManager::InsertHostCache2(MYSQL * connecthandle, char * sessionid, char * channelid, int ISPtype, / unsigned int eIP, unsigned short eport, unsigned int iIP, unsigned short iport) { //填充结构变量m_sInsertParam strcpy(m_stInsertParam->sessionid, sessionid); strcpy(m_stInsertParam->channelid, channelid); m_stInsertParam->ISPtype = ISPtype; m_stInsertParam->externalIP = eIP; m_stInsertParam->externalPort = eport; m_stInsertParam->internalIP = iIP; m_stInsertParam->internalPort = iport; //执行statement,性能瓶颈处 if(mysql_stmt_execute(m_stInsertStmt)) return false; return true; }
