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ASF GitHub Bot commented on NIFI-2854: -------------------------------------- Github user markap14 commented on a diff in the pull request: https://github.com/apache/nifi/pull/1202#discussion_r87631735 --- Diff: nifi-framework-api/src/main/java/org/apache/nifi/controller/repository/claim/ResourceClaim.java --- @@ -64,4 +64,28 @@ * @return <code>true</code> if the Resource Claim is in use, <code>false</code> otherwise */ boolean isInUse(); + + + /** + * Provides the natural ordering for ResourceClaim objects. By default they are sorted by their id, then container, then section + * + * @param other other claim + * @return x such that x <=1 if this is less than other; --- End diff -- Hmmm this is a very odd comment in the code. will address. > Enable repositories to support upgrades and rollback in well defined scenarios > ------------------------------------------------------------------------------ > > Key: NIFI-2854 > URL: https://issues.apache.org/jira/browse/NIFI-2854 > Project: Apache NiFi > Issue Type: Improvement > Components: Core Framework > Reporter: Mark Payne > Assignee: Mark Payne > Fix For: 1.1.0 > > > The flowfile, swapfile, provenance, and content repositories play a very > important roll in NiFi's ability to be safely upgraded and rolled back. We > need to have well documented behaviors, designs, and version adherence so > that users can safely rely on these mechanisms. > Once this is formalized and in place we should update our versioning guidance > to reflect this as well. > The following would be true from NiFi 1.2.0 onward > * No changes to how the repositories are persisted to disk can be made which > will break forward/backward compatibility and specifically this means that > things like the way each is serialized to disk cannot change. > * If changes are made which impact forward or backward compatibility they > should be reserved for major releases only and should include a utility to > help users with pre-existing data convert from some older format to the newer > format. It may not be feasible to have rollback on major releases. > * The content repository should not be changed within a major release cycle > in any way that will harm forward or backward compatibility. > * The flow file repository can change in that new fields can be added to > existing write ahead log record types but no fields can be removed nor can > any new types be added. Once a field is considered required it must remain > required. Changes may only be made across minor version changes - not > incremental. > * Swap File storage should follow very similar rules to the flow file > repository. Adding a schema to the swap file header may allow some variation > there but the variation should only be hints to optimize how they're > processed and not change their behavior otherwise. Changes are only permitted > during minor version releases. > * Provenance repository changes are only permitted during minor version > releases. These changes may include adding or removing fields from existing > event types. If a field is considered required it must always be considered > required. If a field is removed then it must not be a required field and > there must be a sensible default an older version could use if that value is > not found in new data once rolled back. New event types may be added. > Fields or event types not known to older version, if seen after a rollback, > will simply be ignored. -- This message was sent by Atlassian JIRA (v6.3.4#6332)