Re: Oracle's use of tablespaces

grimes_at_access.digex.net (Seth Grimes) writes:

>Why does Oracle use tablespaces? On the balance, they seem unnecessarily
>complicated given the advantages they offer.
 

>Tablespaces are reminiscent (to me) of the IBM mainframe world: allocate a
>file and then create it. It would make more sense to me to create the file
>with some quota mechanism to limit it size or the number of extents, but not
>actually tie up disk space that's not used, which is what happens with
>tablespaces (or am I not using them correctly?). If a query needs a lot of
>disk space, say for a sort or temporary tables, let the server grab the space
>for the duration of the operation and then free it to the OS when the
>operation ends. Oracle seems to need permanently allocated space, however.
>For instance, I recently had to create a 50M TEMP tablespace for a query
>joining a 10k-row table with a 1k-row table. Why should this space persist
>after I'm done this query? For comparison, Ingres allows the DBA to specify

    What would you do with the freed space if you had it ? You probably     would not want to use it up since the next time you wish to run a     query you'll need it back.

   What happens when you guess wrong and the OS can't grab the space it    needs ? What should the query do ? Abort ? In a real production    environment, this kind of mistake can be very costly. I think Oracle    is just taking the safest road. Make sure space is available no    matter what else is going on.

Rich Holowczak
Rutgers University
holowcza_at_andromeda.rutgers.edu Received on Mon Aug 30 1993 - 14:06:57 CEST