Re: Simultaneous long sql operations

Joe Smith wrote:

> Hi,
>
> If I have several long sql operations, involving lots of I/O, what is the
> correct reasoning?:
> 1 - Execute them one by one, so the disk doesn't have to go back and forth
> for the different requests.
> 2 - Execute them in parallel, so oracle can more efficiently 'program' the
> reads and writes to perform.
>
> I guess 1 reduces the response time of each individual request, and 2
> reduces the total time.
>
> If 2 is correct, I was wondering... What's the point of individual execution
> plans? I guess the plans are changed 'on the fly', or something like that,
> depending on the requests arriving.
>
> Thanks in advance.

Is this a single-user Oracle database? If not what you do or do not do in your session will have a negligable impact on disk heads going anywhere or doing any thing.

Is there a reason to believe you are i/o bound or just that there is a lot of i/o?

-- 
Daniel A. Morgan
University of Washington
damorgan_at_x.washington.edu
(replace 'x' with 'u' to respond)