Set the cache priority for pages from the specified database. 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_cache_priority interface is
only advisory, and does not guarantee pages will be treated in a specific
The priority argument must be set to one of the following values:
- The lowest priority: pages are the most likely to be discarded.
- The next lowest priority.
- The default priority.
- The next highest priority.
- The highest priority: pages are the least likely to be discarded.
The Db::set_cache_priority method configures a database, not only operations performed
using the specified Db handle.
The Db::set_cache_priority interface may be called at any time during the life of
The Db::set_cache_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.
The Db::set_cache_priority method may fail and throw an exception or return a non-zero error for errors specified for other Berkeley DB and C library or system methods.
If a catastrophic error has occurred, the Db::set_cache_priority method may fail and
either return DB_RUNRECOVERY or throw a
in which case all subsequent Berkeley DB calls will fail in the same way.
Databases and Related Methods
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