As others have pointed out, the need to cache
a large table should always be questioned carefully.
Having said that, your best bet is probably to create
a KEEP pool (parameter db_buffer_pool_keep in 8.1,
db_keep_cache_size in 9), and assign the table to
the KEEP pool in its STORAGE declaration.
Pro: It is in memory
Con: You must buy the memory. You must be sure you don't cause the box to
start paging to swap ... very bad ... VERY bad.
When you live in the land of bad applications, sometimes the politics of the
situation are such that you just do what you know is the equivalent of
Title: RE: Caching a huge table's data in memory
I don't think a cache table is actually pinned in memory. It just means
that its blocks stick around once they are read and are not recycled as
much as normal tables. That having been said, due diligence should be
taken to tune the queries
I have never delved into just what gets cache and how permanently it gets
cached when a table is cached. In the case of a monstrosity of an
application, to cache or not to cache (that is the question) a large table,
is a case of tweedle-dee and tweedle-dum. But when people are grabbing at
any
Title: RE: Caching a huge table's data in memory
Read
Cary Millsap's papers on Misunderstandings about Oracle Internals at his site www.hotsos.com. They are
excellent!
-Original Message-From: Orr, Steve
[mailto:[EMAIL PROTECTED]]Sent: Tuesday, January 07, 2003 9:54
AMTo
Title: RE: Caching a huge table's data in memory
Searched the site and found nada relating to this topic. Are you saying
something in that paper (wherever it is) contradicts the below, like cache
tables ARE pinned in memory? Is this just a general recommendation or do you
havespecifics about
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
Not a good idea. How big is your table and how much physical memory do you
got?
Why such a requirement, any reasons for that?
-Original Message-
[mailto:[EMAIL PROTECTED]]
Sent: Monday, January 06, 2003 11:54 PM
To: Multiple recipients of list ORACLE-L
Hi List,
I have a
