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BrownBrown BagBag Session #1Session #1
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sperrorlogsperrorlog
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sperrorlogsperrorlog
y A step further:
DBA can possibly set up a single table for all
users SQL*PLUS session audit?
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New memory parametersNew memory parameters
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New memory parametersNew memory parameters
y Prior to Oracle 11g, the DBA set the sga_targetand sga_max_size parameters, allowing Oracleto reallocate RAM within the SGA.
y The PGA was independent, as governed by thepga_aggregate_target parameter.
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New memory parametersNew memory parameters
y In Oracle 11g, the automatic memory management feature isdeveloped. Both SGA and PGA will expand and shrink based on the
instance demands.
y To enable this feature, set the following new parameters:
MEMORY_TARGET sets the system-wide usablememory that will be used by theinstance for SGA and PGA.
MEMORY_MAX_TARGET
(optional)
sets the maximum value you can
set for MEMORY_TARGETparameter.
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DRCPDRCP
Up until the Oracle 11g release, you could
use two ways to connect user sessions:
dedicated server process
shared server process
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DedicatedDedicated
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SharedShared
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Shared Server AnalogyShared Server Analogy
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DRCP in 11gDRCP in 11g
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DRCPDRCPy Consider an application in which the memory required
for each session is 400 KB and the memory requiredfor each server process is 4 MB.The pool size is 100and the number of shared servers used is 100.
y If there are 5000 client connections, the memory usedby each configuration is as follows:
y Dedicated ServerMemory used = 5000 X (400 KB + 4 MB) = 22 GB
y Shared ServerMemory used = 5000 X 400 KB + 100 X 4 MB = 2.5
GBy Database Resident Connection Pooling
Memory used = 100 X (400 KB + 4 MB) + 5000x35KB= 615 MB
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Dedicated Servers Shared Servers
Database Resident Connection
Pooling
When a client request is received, a
new server process and a session are
created for the client.
When the first request is received from
a client, the Dispatcher process places
this request on a common queue. The
request is picked up by an available
shared server process. The Dispatcher
process then manages the
communication between the client and
the shared server process.
When the first request is received from
a client, the Connection Broker picks an
available pooled server and hands off
the client connection to the pooled
server.
If no pooled servers are available, the
Connection Broker creates one. If the
pool has reached its maximum size, the
client request is placed on the wait
queue until a pooled server is available.
Releasing database resources involves
terminating the session and server
process.
Releasing database resources involves
terminating the session.
Releasing database resources involves
releasing the pooled server to the pool.
Memory requirement is proportional to
the number of server processes andsessions. There is one server and one
session for each client.
Memory requirement is proportional to
the sum of the shared servers andsessions. There is one session for
each client.
Memory requirement is proportional to
the number of pooled servers and theirsessions. There is one session for
each pooled server.
Session memory is allocated from the
PGA.
Session memory is allocated from the
SGA.
Session memory is allocated from the
PGA.
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Thank you.Thank you.
Now I have tossed a brick, hopefully will
attract a piece of gold .
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