Berkeley DB: Db.set_cache_priority
Description: Berkeley DB: An embedded database programmatic toolkit.
Keywords: embedded,database,programmatic,toolkit,b+tree,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,java,C,C++

# Db.set_cache_priority |

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    import com.sleepycat.db.*;

    public void set_cache_priority(int priority)
        throws DbException;

# Description

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 way.

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

Db.DB_PRIORITY_VERY_LOW
  The lowest priority: pages are the most likely to be discarded.
Db.DB_PRIORITY_LOW
  The next lowest priority.
Db.DB_PRIORITY_DEFAULT
  The default priority.
Db.DB_PRIORITY_HIGH
  The next highest priority.
Db.DB_PRIORITY_VERY_HIGH
  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 application.

The Db.set_cache_priority method throws an exception that encapsulates a non-zero error value on failure.

# Errors

The Db.set_cache_priority method may fail and throw an exception 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 throw a DbRunRecoveryException, in which case all subsequent Berkeley DB calls will fail in the same way.

# Class

Db

# See Also

Databases and Related Methods`

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