Re: Sequences

On Sat, 03 Aug 1996 19:41:19 -0700, Michael Wilson <mkwilson_at_well.com> wrote:

>I have a couple of questions about sequences:
>
>1. Just how lightweight are sequences? From what I've read, they seem to
>provide a unique # for any number of requestors, without all the muss
>and fuss of creating a counter in a row, and going through the overhead
>of locking, etc; to maintain it. Right?
>

Right. Sequences are non-blocking, multi-user, primary key generators in a manner of speaking.

>2. How many sequences can I have? We have an application which
>potentially require thousands of individual sequences, but's it's
>unclear how much overhead each one takes. From my reading, it looks like
>sequences are stored in the data dictionary, but does each one consist
>merely of a row?
>
As many as you want. The sequence definition takes but an entry in the data dictionary and a little ram at run time in the SGA (to store the cached definition of the sequence like any other object in the database).

>Thanks in advance..

Thomas Kyte
Oracle Government
tkyte_at_us.oracle.com                          

http://govt.us.oracle.com -- Check out our web site! Brand new, uses Oracle Web Server and Database

statements and opinions are mine and do not necessarily reflect the opinions of Oracle Corporation Received on Mon Aug 05 1996 - 00:00:00 CEST