DB_MPOOLFILE->set_priority()

#include <db.h>

int
DB_MPOOLFILE->set_priority(DB_MPOOLFILE *mpf, DB_CACHE_PRIORITY priority);

Set the cache priority for pages referenced by the DB_MPOOLFILE handle.

The priority of a page biases the replacement algorithm to be more or less likely to discard a page when space is needed in the cache. The bias is temporary, and pages will eventually be discarded if they are not referenced again. The DB_MPOOLFILE->set_priority() method is only advisory, and does not guarantee pages will be treated in a specific way.

To set the priority for the pages belonging to a particular database, call the DB_MPOOLFILE->set_priority() method using the DB_MPOOLFILE handle returned by the DB->get_mpf() method.

The DB_MPOOLFILE->set_priority() method configures a file in the cache, not only operations performed using the specified DB_MPOOLFILE handle.

The DB_MPOOLFILE->set_priority() method may be called at any time during the life of the application.

The DB_MPOOLFILE->set_priority() method returns a non-zero error value on failure and 0 on success.

Parameters

priority

The priority parameter must be set to one of the following values:

DB_PRIORITY_VERY_LOW

The lowest priority: pages are the most likely to be discarded.
DB_PRIORITY_LOW

The next lowest priority.
DB_PRIORITY_DEFAULT

The default priority.
DB_PRIORITY_HIGH

The next highest priority.
DB_PRIORITY_VERY_HIGH

The highest priority: pages are the least likely to be discarded.

Class

DB_ENV, DB_MPOOLFILE