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Re: Oracle Shared Mode for

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Date: Sun, 17 Jun 2007 23:01:27 +0200
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On Sun, 17 Jun 2007 13:09:00 -0700, cablito <> wrote:

>It seems some DBAs have some sort of problem with using Oracle shared
>mode vs. dedicated.
>What happens is, we have several Asp.Net sites that consume the oracle
>database. Each site, thus application uses a pool of 30 or
>more connections. Given the fact we have around 10 active sites,
>sometimes there are 200 ~ 300 connections to Oracle.
>Out of those 200 connections, most of them spend more time in idle
>than not, around 30 active conections for 170 idle, which of course as
>uses browse the sites changes a little.
>We are using AIX as operating system, and have 8GB of RAM (yeah, don't
>even get me started on that).

Should be sufficient
>Because each connection uses somewhere from 20 to 60 MB, that is
>trashing the memory usage.

Shouldn't be a problem
>When using Shared mode, memory usage obviously goes way lower even if
>setting the number of dispatchers to 10.
Typical the number of dispatchers should be low. 10 is way too much. You are confusing servers and dispatchers.l
>Is there a good reason why not to use Shared mode? Considering the
> typical behaviour.

There are many good reasons.
1 200 sessions shouldn't be a problem
2 shared server is unsuited for long running queries 3 shared server has overhead.
>Why do, not one or two, but a few dbas insist in believing Dedicated
>is the only way you should use oracle.

With a number of connection as low as 200 there should be little reason for shared server.
>By the way, anyone has any AIX tips, is it just me or is AIX a pain!?

It is you. Apart from that, either you or your developers, or both parties don't have a clue about Oracle. You are thrashing the system by setting the SGA way too high (See your other post).
>Thanks in advance,

No thanks.

Sybrand Bakker
Senior Oracle DBA
Received on Sun Jun 17 2007 - 16:01:27 CDT

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