Db::set_priority()

#include <db_cxx.h>

int
Db::set_priority(DB_CACHE_PRIORITY priority); 

Set the cache priority for pages referenced by the Db 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::set_priority() method is only advisory, and does not guarantee pages will be treated in a specific way.

When called on a database that has been opened with sliced support, the Db::set_priority() method is automatically called on each supporting slice database.

The Db::set_priority() method may be called at any time during the life of the application.

The Db::set_priority() method either returns a non-zero error value or throws an exception that encapsulates a non-zero error value on failure, and returns 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

See Also

Database and Related Methods