Extent sizes

ar@mai.de wrote: AR> I would like to have a better feeling about the performance impact > of the definition of extent sizes (first and next) for tables. It is important that you don't have too many extents, because you are in effect dealing with a fragmented drive if you do. AR> In our production database ( Online 5.01 ) we have already tables with > about 50 extents. tbcheck already gives a warning at 8 extents. Yes, you must try and resolve this. AR> Are there any experiences or guidelines of configuring the first and > next extent size the best way? (Row size + index size) * no of rows of your existing data or estimated first year of data for each table to set your extent size. Thereafter, thumbsuck the total size of your database ever and see that the remaining records fit into no more than 8 extents (including your initial extent). AR> How big can the performance degradation be if configured in a bad way ? > ( access is n times slower ? Which n ) Sjoe, I have no idea. All I know is it *IS* noticeably slower. AR> Is it possible to change these for the system tables as well? These > tables were the first ones exceeding the warning level of 8 extents! Amazing! Do you have a lot of tables, or are they very wide? This one is beyond my humble experience! I'm not sure if this would cause any problems, and I can't think of any way around it. In general, a dbexport / dbimport is a good idea, but that wouldn't help for the system catalogs. Johnathan? Regards, billy.wheeler@digitec.co.za --- . SPEED 1.40 [NR] . Aside from that Mrs. Kennedy, how was the parade? ---- Digitec Online - 20 Nodes....* Johannesburg, South Africa +27-11-476-2008 .............................* Best BBS * RsaNET User Choice Awards 1993 first.last@digitec.co.za.....* Best Sysop * RsaNET User Choice Awards 1993