提高MySQL 查询效率的三个技巧

_lsIdleList.push_back(connecthandle);       m_ListMutex.release();}//使用示例,首先获取空闲句柄,利用这个句柄做真正的操作,然后再插回到空闲队列bool CDBManager::DeleteHostCacheBySessionID(char * sessionid){       MYSQL * pConnectHandle = GetIdleConnectHandle();       if(!pConnectHandle)              return 0;       bool bRet = DeleteHostCacheBySessionID(pConnectHandle, sessionid);       SetIdleConnectHandle(pConnectHandle);       return bRet;}//传入空闲的句柄,做真正的删除操作bool CDBManager::DeleteHostCacheBySessionID(MYSQL * connecthandle, char * sessionid){       char deleteSQL[SQL_LENGTH];       memset(deleteSQL, 0, sizeof(deleteSQL));       sprintf(deleteSQL,"delete from HostCache where SessionID = '%s'", sessionid);       if(mysql_query(connecthandle,deleteSQL) != 0) //删除              return false;       return true;}