Re: How much RAM does Oracle REALLY use?

suskind_at_bbs.mdcbbs.com writes:

>I have a dispute between my Oracle DBA and my Unix system manager
 

>I am running Oracle V6 on a SCO Unix system with 40 Megabytes of RAM.
 

>My Unix system manager says the system is swapping and needs more memory
>and Oracle is the cause. My Oracle DBA says the system needs to be tuned
>and Oracle could not possibly be using that much memory.
 

>The Unix system manager is running "monitor" a product from Stallion
>Technologies. Looking at the memory display he can see 4 background Oracle
>tasks (PMON, DBWR, LGWR, SMON) each taking up 4.0 megabytes for a total of
>16 megabytes. When the system gets about 25 users on running a variety of
>processes (Office Portfolio, Word Perfect, etc) the system runs out of
>memory.
 

>I have no problem here, all of this stuff DOES use lots of RAM. My problem
>is the Oracle DBA saying that Oracle could not POSSIBLY be using that much
>memory. As my DBA has stated (quoting from the UNIX install book) the RDBMS
>requires 1,790 KBytes of RAM + 1,100 KBytes of RAM for shared memory. Each
>SQLplus process requires 356 KBytes of RAM for shared memory plus 93 KBytes
>for each user. Each SQLforms (v2.3) uses 474 KBytes of RAM for shared
>memory plus 62 KBytes for each user. The communications area uses 3,779
>KBytes of RAM for the Shared Global Segment plus 4 KBytes per user.
 

>This does not anywhere near compare to what this monitor program displays,
>and yet when the system gets loaded, the system does swap (as indicated by
>the UNIX tools "vmstat" and "ps", and by the "monitor" program.
 

>Who is correct? It is my feeling that to information in the Oracle book
>does NOT include the required memory to LOAD the program into memory, and
>the PMON, SMON, DBWR, and LGWR processes require 4 megabytes a piece. Does
>anybody real info here? My DBA has called Oracle and that have quoted what
>is in the book.

and what does the sga look like?
how many, how big are the various buffers?

bill

--
bill_at_chaos.cs.umn.edu