7.3.12 USE_LARGE_PAGES Default Value Set To AUTO_ONLY

On Oracle Exadata, starting with Oracle Database 19c, the default value for the USE_LARGE_PAGES database initialization parameter is AUTO_ONLY. This setting provides a simple mechanism allowing databases to automatically use large memory pages (also known as huge pages) to contain the Oracle Database System Global Area (SGA) without any system administration effort.

During startup, when USE_LARGE_PAGES=AUTO_ONLY, the database calculates the number of large pages required by the SGA and dynamically requests them from the operating system. If the request is successful, the database starts up with the SGA contained in the large memory pages. If the operating system cannot satisfy the requirement, then the database fails to start.

Note:

To maximize performance and stability, Oracle recommends always using large memory pages for the SGA. However, dynamic acquisition of large memory pages can fail when system memory is fragmented or when multiple databases start concurrently. Consequently, Oracle recommends setting USE_LARGE_PAGES to ONLY.

In line with these recommendations, new databases created using Exadata automation tools are configured with USE_LARGE_PAGES=ONLY by default. This includes databases created using Oracle Exadata Deployment Assistant (OEDA) and databases created on a cloud-based Exadata deployment (using Exadata Database Service).

When USE_LARGE_PAGES=ONLY, the database fails to start if insufficient large pages are available to contain the SGA. In this case, the system administrator must configure the operating system to ensure enough large pages are available to cover all databases.