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Oracle instances and performance [message #224349] Wed, 14 March 2007 01:04 Go to next message
subratd
Messages: 12
Registered: March 2007
Junior Member
I have a querry that if the number of instances in an oracle session increases, then will it hamper the performance of querries running on the database.If yes, could any one please explain me the reason behind it.
Re: Oracle instances and performance [message #224353 is a reply to message #224349] Wed, 14 March 2007 01:21 Go to previous messageGo to next message
rleishman
Messages: 3724
Registered: October 2005
Location: Melbourne, Australia
Senior Member
Explain what you mean by "Instance".
Re: Oracle instances and performance [message #224356 is a reply to message #224353] Wed, 14 March 2007 01:25 Go to previous messageGo to next message
subratd
Messages: 12
Registered: March 2007
Junior Member
Instance is the collection of memory structures and oracle background processes. In general, we can say when a user say SCOTT logs in to a database, by giving usrname and pwd, an instance is started in the database.
Re: Oracle instances and performance [message #224456 is a reply to message #224349] Wed, 14 March 2007 06:22 Go to previous messageGo to next message
gintsp
Messages: 118
Registered: February 2007
Senior Member
Probably you can show us the query (if it is one query) or somehow describe the proc (if it is procedure and a long one).

There are many ways when one query may run well for one single user but it may slow down everything when used by many users.

Generally everything slows down if the proc uses too much resources (I/O, CPU) or the proc just blocks other users.

Gints Plivna
http://www.gplivna.eu
Re: Oracle instances and performance [message #224511 is a reply to message #224356] Wed, 14 March 2007 08:35 Go to previous message
JRowbottom
Messages: 5933
Registered: June 2006
Location: Sunny North Yorkshire, ho...
Senior Member
Quote:
Instance is the collection of memory structures and oracle background processes. In general, we can say when a user say SCOTT logs in to a database, by giving usrname and pwd, an instance is started in the database.


That is half right, but you've got your terminology quite badly confused.
The Instance is what you connect to when you issue a connect command.
When you do issue a connect command, you create a Session inside that Instance of the database - you do not create an Instance in a database.
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