#include <db.h>

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

int
DB_MPOOLFILE->get_priority(DB_MPOOLFILE *mpf, DB_CACHE_PRIORITY *priorityp);

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 buffer pool. 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 memory pool, 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.

• 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.
  
  

The DB_MPOOLFILE->get_priority method returns the cache priority for the file referenced by the DB_MPOOLFILE handle.

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

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

• The DB_MPOOLFILE->get_priority method returns a reference to the cache priority for the file referenced by the DB_MPOOLFILE handle in priorityp.