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https://issues.apache.org/jira/browse/JDO-651?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13937948#comment-13937948
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Andy Jefferson commented on JDO-651:
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Clarification :
When using optimistic txns commit/flush could still throw
JDOOptimisticVerificationException (since an implementation will not have
applied the changes to the datastore, so can still check the datastore for
version updates before persisting) and rollback could throw away changes if not
yet flushed (i.e PDIRTY -> HOLLOW).
When using datastore txns then the implementation is at liberty to push changes
to the datastore at any time (just as it can for RDBMS) so
commit/flush/rollback likely will be no-op (unless the implementation is
queuing changes of course). Once changes have been flushed then rollback will
be no-op (in terms of the datastore, since there is no way of backing the
changes out).
> Modify specification to address NoSQL datastores
> ------------------------------------------------
>
> Key: JDO-651
> URL: https://issues.apache.org/jira/browse/JDO-651
> Project: JDO
> Issue Type: New Feature
> Components: api, specification, tck
> Affects Versions: JDO 3 (3.0)
> Reporter: Matthew T. Adams
> Assignee: Matthew T. Adams
> Labels: jdo, nosql, profile, specification
> Fix For: JDO 3 maintenance release 2 (3.2)
>
>
> There is increasing interest in NoSQL datastores (Google BigTable, Apache
> HBase, VMWare Redis, etc), which not only do not support SQL, but also do not
> necessarily provide support for traditional consistency or queriability
> features or guarantees, instead offering features like eventual consistency,
> key-value storage mechanisms, etc.
> This request is to modify the JDO specification (and TCK & RI) so that it
> relaxes certain portions of the specification, perhaps in the form of
> profiles similar to JavaEE 6 profiles, to allow datastores that may not
> support queries in general, do not support the ACID requirements, or that
> support key-value-based storage mechanisms to be JDO-compliant. Additions to
> the specification may also be needed in order to directly address NoSQL-type
> datastores, in a manner similar to its treatment of relational persistence
> mechanisms.
> Additionally, this request would serve to better support persistence on micro
> platforms where consistency, queriability, etc, may not be supported.
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