Re: Why Heap Tables doesn´t support auto increment colums
On Thu, Mar 01, 2001 at 11:47:41AM -0500, Joe Kislo wrote: > > I´m currently working on system for Managing http Session and would like > > to use a heap table for storing the session information. Session > > information is only of temporary intrest. But still I need an unique > > ID for reference with some other Tabels storing dtaa for the session. > > All these tables are Heap tables. So there is no Probelem if the ID > > generated by the auto_increment column is not unique when the Database > > server is restarted. > > There's a couple problems with that to begin with. First, you're > storing state in a HEAP table. If the mysql server gets reset, all the > sessions are lost. It would be tough to think you want to write your > system so your database server cannot ever be restarted, especially when > writing the data to a MyISAM table would probably be at a trivial loss > of speed. Read my mail. The data I store is only of temporary intrest. So there is no Problem when they are lost during mysqlserver restart. > Also, if you used an auto_incrementing column, you would be > handing out sessionIDs sequentially. It would be trivial for somebody > to usurp somebody else's sessionID by simply subtracting or adding 1 to > their own. There is now way for an user to see the session ID. The Session ID is internaly handled and retrieved from the database every single request. Thats why I want to use Heap Tables to reduse overhead. The System is working perfektly. Solong Estartu -- Gerhard Schmidt mailto:[EMAIL PROTECTED] Softwaredevelopment adMaster network Tel.: +49 89 38356-334 Kaiserstraße 16 D-80801 München http://www.admasternetwork.net PGP signature
Re: Antwort: Re: Why Heap Tables doesn´t support auto increment ?colums
On Thu, Mar 01, 2001 at 02:37:30PM +0100, Entryon Corp., Chief Technical Officer - P. Hasenfratz wrote: > > > Why not use a timestamp column to guarentee the order in which rows get > > > inserted into the table? You can then order on the timestamp column. > > > > Hmm, timestamp, ie. seconds as finest resolution, might be to broad > depending on > > the hits his site will get - imagine that 2+ users access the site in the > same > > second, then you won't be able to distinguish them, will you? > > What's if you combine a timestamp with the client's IP address? > > for example: > > 5/6/2001 > IP : 212.33.69.2 > > => clientstamp will be 05.06.2001-212.033.069.002 Besides the fakt tha this ID not unique. There ist the Problem that the ID you proposed ist an String ID and strings als Index are the Major Preformance killer on Databases. Wie kann calculate an intager from the two information. totaly loosing the Uniqueness. The question still is. Why are auto_increment columns are not supported fuer Heap Tables. SoLong Estartu -- Gerhard Schmidt mailto:[EMAIL PROTECTED] Entwicklung adMaster network Tel.: +49 89 38356-334 Kaiserstraße 16 D-80801 München http://www.admasternetwork.net PGP signature
Why Heap Tables doesn´t support auto_increment colums
Hi, I wounder why there is no support for Auto_increment fields in Heap tables. I know there is a problem with the uniqueness of this columns but some times the uniqueness of the column is only needes as long as the heap table exists. I´m currently working on system for Managing http Session and would like to use a heap table for storing the session information. Session information is only of temporary intrest. But still I need an unique ID for reference with some other Tabels storing dtaa for the session. All these tables are Heap tables. So there is no Probelem if the ID generated by the auto_increment column is not unique when the Database server is restarted. So Long Estartu -- Gerhard Schmidt mailto:[EMAIL PROTECTED] Softwaredevelopment adMaster network Tel.: +49 89 38356-334 Kaiserstraße 16 D-80801 München http://www.admasternetwork.net PGP signature
