Re: 2GB limit of memory for Oracle on WIndows 32 bit

On Jul 1, 12:37 pm, zigzag..._at_yahoo.com wrote:
> On Jul 1, 11:41 am, sybra..._at_hccnet.nl wrote:
> > Apart from that cranking up the memory won't resolve your fundamental
> > problem: apparently you never tuned your application and now you want
> > to resolve that by throwing memory at the problem.
> > This method has been demonstrated to be fundamentally wrong over and
> > over again, and is one of the safest methods to end up in hell or at
> > the unemployment office.
>
> > --
> > Sybrand Bakker
> > Senior Oracle DBA-
>
> FYI, keep and recycle pools work exactly the same way. keep and
> recycle are just the names given by Oracle. Vendor sells the
> application, I cannot do any tuning of application.

The above comment is interesting. I recall reading in several places that the keep pool tries to keep blocks in memory, much like the default pool, while the recycle pool tries to quickly age blocks out of the pool. After a bit of a search, I found a bit of disagreement. The results of the search follow:

"Expert Oracle Database 10g Administration" paraphrase: The recycle buffer pool will cycle out the objects read out of the cache as soon as the transaction ends.

"Oracle Database Concepts 10g Release 2 (10.2)": http://download.oracle.com/docs/cd/B19306_01/server.102/b14220/memory.htm#sthref1291 The KEEP buffer pool retains the schema object's data blocks in memory.
The RECYCLE buffer pool eliminates data blocks from memory as soon as they are no longer needed.
The DEFAULT buffer pool contains data blocks from schema objects that are not assigned to any buffer pool, as well as schema objects that are explicitly assigned to the DEFAULT pool.

"Oracle8 Concepts Release 8.0":
http://download-east.oracle.com/docs/cd/A58617_01/server.804/a58227/ch_mem.htm The KEEP buffer pool retains the schema object's data blocks in memory.
The RECYCLE buffer pool eliminates data blocks from memory as soon as they are no longer needed.
The DEFAULT buffer pool contains data blocks from schema objects that are not assigned to any buffer pool, as well as schema objects that are explicitly assigned to the DEFAULT pool.

"Expert Oracle One on One" Page 80:
"We also have the ability to carve out a space for segments in the buffer pool. This space is called the RECYCLE pool. Here, the aging of the blocks is done differently to the KEEP pool. In the KEEP pool, the goal is to keep 'warm' and 'hot' blocks cached for as long as possible. In the recycle pool, the goal is to age out a block as soon as it is no longer needed."

http://www.jlcomp.demon.co.uk/faq/pin_table.html "NOTE: there is no difference in the behavior of the three buffer pools, the naming of the pools is merely for memo technically reasons and intended use."

http://forums.oracle.com/forums/thread.jspa?threadID=524119 - look for the posting by Jonathan Lewis for context: "You will rarely be able to beat Oracle's caching algorithms by playing with KEEP and RECYCLE pools - but there are a few special cases..."

Charles Hooper
IT Manager/Oracle DBA
K&M Machine-Fabricating, Inc. Received on Sun Jul 01 2007 - 21:47:26 CDT