Memory tuning guidelines for Oracle databases

Applies to: On premises

If your application is running in a heavy-load environment, consider allocating as much memory as possible to the Oracle database instance.

The following table provides general guidelines for memory allocation on a system with 8 GB of RAM or more.

Table 1. Memory tuning guidelines for computer with 8 GB of RAM

For this...

Allocate...

Operating system

2 GB of physical RAM for the Windows OS.

SGA Size

75% of remaining physical RAM to the SGA_TARGET parameter.

Minimum allocation: 4608 MB (or 4.5 GB).

PGA Size

25% of remaining physical RAM to the PGA_AGGREGATE_TARGET parameter.

Minimum allocation: 1536 MB (or 1.5 GB).

Pluggable databases

If you are using Oracle PDB, ensure that you set the tuning parameters on the pluggable database.

Computers with multiple database instances

Note: If you are planning to run multiple database instances on the same computer, adjust the memory to ensure that concurrently running instances fit into the available physical RAM. Using physical memory avoids swapping to disk.

For example, to run the IBM OpenPages® database and Cognos® database services on the same computer with 8 GB of RAM:

  • 2 GB of RAM for the OS
  • The remaining 6 GB of RAM can be split between the OpenPages database and Cognos database as follows:
    • OpenPages database instance: 2.5 GB SGA + 1 GB PGA
    • Cognos database instance: 1.5 GB SGA + 1 GB PGA