[JCR-3534] Efficient copying of binaries across repositories with the same data store

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.6
• Fix Version/s: 2.6.2, 2.7.1
• Component/s: jackrabbit-api, jackrabbit-core
• Assignee: Tommaso Teofili
• Reporter: Felix Meschberger
• Created: 15/Mar/13 13:50
• Updated: 21/Jul/15 08:56
• Resolved: 21/May/13 10:33

Description

we have a couple of use cases, where we would like to leverage the global data store to prevent sending around and copying around large binary data unnecessarily: We have two separate Jackrabbit instances configured to use the same DataStore (for the sake of this discussion assume we have the problems of concurrent access and garbage collection under control). When sending content from one instance to the other instance we don't want to send potentially large binary data (e.g. video files) if not needed.

The idea is for the sender to just send the content identity from JackrabbitValue.getContentIdentity(). The receiver would then check whether the such content already exists and would reuse if so:

String ci = contentIdentity_from_sender;
try {
Value v = session.getValueByContentIdentity(ci);
Property p = targetNode.setProperty(propName, v);
} catch (ItemNotFoundException ie) {
// unknown or invalid content Identity
} catch (RepositoryException re) {
// some other exception
}

Thus the proposed JackrabbitSession.getValueByContentIdentity(String) method would allow for round tripping the JackrabbitValue.getContentIdentity() preventing superfluous binary data copying and moving.

See also the dev@ thread http://jackrabbit.markmail.org/thread/gedk5jsrp6offkhi

Issue Links

• is related to: JCR-3448 Enable support for refferring to blobs which are stored directly to datastore backend
• is related to: JCRVLT-97 Implement binaryless export