MySQL由于它本身的小巧和操作的高效, 在數(shù)據(jù)庫應(yīng)用中越來越多的被采用.我在開發(fā)一個P2P應(yīng)用的時候曾經(jīng)使用MySQL來保存P2P節(jié)點,由于P2P的應(yīng)用中,結(jié)點數(shù)動輒上萬個,而且節(jié)點變化頻繁,因此一定要保持查詢和插入的高效.以下是我在使用過程中做的提高效率的三個有效的嘗試. 1、使用statement進(jìn)行綁定查詢 使用statement可以提前構(gòu)建查詢語法樹,在查詢時不再需要構(gòu)建語法樹就直接查詢.因此可以很好的提高查詢的效率. 這個方法適合于查詢條件固定但查詢非常頻繁的場合. 使用方法是： 綁定, 創(chuàng)建一個MYSQL_STMT變量,與對應(yīng)的查詢字符串綁定,字符串中的問號代表要傳入的變量,每個問號都必須指定一個變量. 查詢, 輸入每個指定的變量, 傳入MYSQL_STMT變量用可用的連接句柄執(zhí)行. 代碼如下： //1.綁定 bool CDBManager::BindInsertStmt(MYSQL * connecthandle) { //作插入操作的綁定 MYSQL_BIND insertbind[FEILD_NUM]; if(m_stInsertParam == NULL) m_stInsertParam = new CHostCacheTable; m_stInsertStmt = mysql_stmt_init(connecthandle); //構(gòu)建綁定字符串 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結(jié)構(gòu)數(shù)組, m_sInsertParam是這個statement關(guān)聯(lián)的結(jié)構(gòu)變量 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; //綁定 if (mysql_stmt_bind_param(m_stInsertStmt, insertbind)) return false; return true; } //2.查詢 bool CDBManager::InsertHostCache2(MYSQL * connecthandle, char * sessionid, char * channelid, int ISPtype, / unsigned int eIP, unsigned short eport, unsigned int iIP, unsigned short iport) { //填充結(jié)構(gòu)變量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; //執(zhí)行statement,性能瓶頸處 if(mysql_stmt_execute(m_stInsertStmt)) return false; return true; }
