ORA–4030, ORA–12500 or ORA–27102 Increase RAM on 32-bit Oracle Windows servers

Error:
ORA–27102 Increase RAM on 32-bit Oracle Windows servers

Cause:
On windows-2003 32-bit SGA memory utilization was restricted to 1.7GB

Issue Detail:
In a Windows environment, Oracle operates as a single process, with all background and server processes running as threads of oracle.exe. These threads share the same virtual memory, limited to 4 GB total, which is divided into 2 GB for user memory and 2 GB for kernel memory. Using the /3GB flag in the boot.ini file changes this split to 3 GB for user memory and 1 GB for kernel memory.

PAE Memory (32-bit architectures) Understanding:

The 32-bit architecture allows for 4 GB of physical memory to be addressed. In order to overcome this limitation, Intel came up with a method of addressing more than 4 GB of RAM. This is done using the Physical Address Extension (PAE). With PAE, the page directories and page tables are extended from 4 byte to 8 byte formats, thus allowing for the base address of page tables to be increased from 20 bits to 24 bits. The net affect is that with PAE up to 64GB of RAM can be addressed.

Solution: Parameter in boot.ini file need to set /3GB /PAE

/3GB flag is recommended for use in systems with up to 4 GB of RAM. In systems with 16GB or more of physical RAM, the use of /3GB and /PAE are mutually exclusive. When running on such a system, the /3GB flag should be used to optimize Oracle for large or many PGAs, while the /PAE flag should be used when many database buffers are required for optimal performance.

Note: The /3GB flag is used to control virtual memory address space, the /PAE flag is used to control physical memory.

You need to edit the boot.ini parameter file
and add it as /3GB .
multi(0)disk(0)rdisk(0)partition(1)\WINNT="MicrosoftWindows2000AdvancedServer" /fastdetect /3GB
need to reboot the window server.
max sga size is in windows 32 bit is 3GB.
3 GB (32-bit) and 8 TB (64-bit) maximum memory per database instance