Hi,
Allow me to be the first of many to ask - why do you want to cache a huge
table in memory? Important questions include:
* Define huge (both in depth [row count] and width [row size])?
* What type of queries are you running against this table?
* What access paths are being used (ie: via index or frequent full table
scans)?
* What is currently in memory and going to be thrown out to make room for
this table? (RAM is a bit like a bus - there are a set number of seats and
you can't let more people on without kicking someone out [despite what
those wierd products in the early 90's tried to convince us])
"alter table [table_name] cache;" is a valid command as far as I know but
I'm sure some experts here will better explain the inner workings of
Oracle. Reading Oracle documentation talks about caching small tables
which are subject to full table scans. The cache instruction (I believe)
simply tells Oracle to put them at the end of the list of things to throw
out, instead of the start. If Oracle had the room is would cache the huge
table anyway without that parameter.
It sounds a little like a developer has told you to cache the table because
someone told him to make the query run faster. Unfortunately it's rarely
that simple.
Regards,
Mark.
"Krishnaswamy, Ranganath"
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Sent by: [EMAIL PROTECTED] Subject: Caching a huge
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07/01/2003 15:53
Please respond to ORACLE-L
Hi List,
I have a requirement for caching the data of a huge table in
memory.
Is it just running the command Alter table <tablename> cache or something
else? What are the pros and cons of caching a table's data? Could anybody
advise me in this regard? Any help in this regard is very much
appreciated.
Thanks and Regards,
Ranganath
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