Integer
Determined by physical memory
Purpose
The DiskCacheMaxSegments parameter specifies the maximum number of segments that the disk cache is to use.
The value of the DiskCacheMaxSegments parameter cannot be less than the value specified for the DiskCacheMinSegments parameter.
The default value is calculated from the size of physical memory. The available memory is half of the size of physical memory divided by 8K bytes (the disk block size), to yield the number of blocks it can contain. The default value for the DiskCacheMaxSegments parameter then becomes that number of blocks divided by the number of blocks per segment.
The maximum value is also calculated from the size of physical memory. When there is 2G bytes or less of physical memory, the available memory is two‑thirds of the size of physical memory; otherwise, it is the size of physical memory less 256M byes. This available memory figure is then divided by 8K bytes (the disk block size), to yield the number of blocks it can contain. The maximum value for the DiskCacheMaxSegments parameter then becomes that number of blocks divided by the number of blocks per segment.
Parameter is read when …
The database server node is initialized; for example, when you restart the database server.