Re: DBMS_PIPE, DBMS_SHARED_POOL

Anurag Srivastava wrote:
>
> Hello,
>
> I need to create a centralized program that can handle data requests
> from a bunch of client sessions running on the same server. I was
> thinking of using DBMS_SHARED_POOL.KEEP to pin this central package in
> SGA memory and have the other programs commmunicate with it using
> DBMS_PIPE.
>
> Questions/Problems:
> 1. What's the overhead associated with having a hundred private
> pipes permanently resident in SGA (after the pipes have been
> purged)? Will it slow things down a lot? What about contention
> between several PGAs trying to talk the same package?
I dont know I only used public pipes.

> 2. When a package is pinned in SGA, I thought only its code
> segment got pinned. A new data segment will probably be
> created in the PGA of every program that's accessing this
> pinned package.
> Hence, it may not be possible to share the data that the
> central package has gathered, which is exactly what I want
> to do, viz. share the same set of data. So will my idea
> work?

I have been doing something similar and each program would have its own data block. The way around it would be to have a centralised program block that used pipes to send/receive the shared information. The other option I looked at was using a table.

> 3. Since the limitation of a pipe's message buffer is 4096 bytes,
> how long will it take to get about 1000 messages thru the pie?
>

Hmm I think you might be getting a little confused here. The 4096 limitiation (from memory) only applies to the size of a message as it is being created.
Each pipe has its own size limit (specified when you create the pipe/send a message) that you can increase. So your message size might be 2500 but your pipe size could be 25000 or 50000.

Can you give me a pointer to more information on DBMS_SHARED_POOL e.g. which manual.

I hope this has helped.

Mark
> If any body has any comments/suggestions, I'd love to hear it.
> Thanks!
>
> Anurag Srivastava
 

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