[HELP ]unexpected low memory usage

Question

Hi all,
Could someone help me out with unexpected low memory usage I am facing when I start the DB instance.
I am running Oracle 8.1.7.3.2 on Windows 2000 Adv Srv with
2GB of RAM and 3GB of swap area.
I only have 1 instance with memory related init parameters setted as below.
shared_pool_size = 293510451
large_pool_size = 104857600
java_pool_size = 20971520
db_block_buffers = 107289
sort_area_size = 1048576
avg of about 150~250session so I was expecting the oracle
to allocate about 1.5GB of RAM when the instance startsup
Now, when I startup the instance, EXPECTING the oracle to
allocate about 1.5GB of RAM for himself, and check the
memory allocation status from the "task manager", it
shows that 1.4GB of physical memory is AVAILABLE. In another words, the whole system is only using 600MB of
physical memory.
Could anyone tell why this is happening and the solution to solve this problem?
BTW, even if I give loads to oracle using the Mercury LoadRunner, the memory allocation status does not change much while oracle is barely processing each transactions.
Thanks, in advance

Answer 1

I work mostly with UNIX but found the following from Metalink document# 46001.1 Oracle Database and the Windows NT memory architecture, Technical Bulletin. I think this answers your question:
On starting up an Oracle instance all global memory pages are reserved and committed (Total Shared Global Area, Buffer Cache and Redo Buffers). Only a small number of these memory pages are touched on startup and are thus not in Oracle's working set, as more pages are touched they will be brought into memory. Oracle must contend equally with other processes and will have its working set trimmed if other processes are faulting at a greater rate.
It is unlikely that this trimming will be desirable, especially when the database has a varying workload (high and low usage periods). Two registry parameters exist to allow the administrator to manipulate the working set bounds of the Oracle process, these are :
- ORA_WORKINGSETMIN or ORA_%SID%_WORKINGSETMIN
: Minimum working set for the ORACLE.EXE process (units = MB)
- ORA_WORKINGSETMAX or ORA_%SID%_WORKINGSETMAX
: Maximum working set for the ORACLE.EXE process (units = MB)
These parameters apply to all releases from 7.3.x and should be added to the Long postings are being truncated to ~1 kB at this time.