[OAK-2291] Associate user defined values with checkpoint

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 1.1.3
• Component/s: core
• Assignee: Michael Dürig
• Reporter: Michael Dürig
• Created: 25/Nov/14 09:06
• Updated: 10/Mar/15 14:34
• Resolved: 02/Dec/14 12:00

Description

For diagnosis, upgrade, migration, maintenance, etc. it would be useful if we could assign user specific properties to checkpoints. This could be used e.g. to record who added a checkpoint (i.e. backup, indexer, ....). This would simplify action taken for example on the checkpoint MBean as one could more easily tell various checkpoints apart.

I therefore suggest to add the following methods to the NodeStore API:

/**
 * Creates a new checkpoint of the latest root of the tree. The checkpoint
 * remains valid for at least as long as requested and allows that state
 * of the repository to be retrieved using the returned opaque string
 * reference.
 * <p>
 * The {@code properties} passed to this methods are associated with the
 * checkpoint and can be retrieved through the {@link #checkpointInfo(String)}
 * method. Its semantics is entirely application specific.
 *
 * @param lifetime time (in milliseconds, &gt; 0) that the checkpoint
 *                 should remain available
 * @param properties properties to associate with the checkpoint
 * @return string reference of this checkpoint
 */
@Nonnull
String checkpoint(long lifetime, Map<String, String> properties);

/**
 * Retrieve the properties associated with a checkpoint.
 *
 * @param checkpoint string reference of a checkpoint
 * @return the properties associated with the checkpoint referenced by
 *         {@code checkpoint} or an empty map when there is no such
 *         checkpoint.
 */
@Nonnull
Map<String, String> checkpointInfo(String checkpoint);

At the same time we should probably deprecate NodeStore#checkpoint(long) in favour or NodeStore#checkpoint(long, Map<String, String>) passing an empty map as its 2nd argument.

Issue Links

• duplicates: OAK-2089 Allow storing some metadata while creating checkpoint