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https://issues.apache.org/jira/browse/OAK-10812?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17850328#comment-17850328
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Manfred Baedke commented on OAK-10812:
--------------------------------------
The problem is the following method, which is called in
DocumentNodeStore#diffManyChildren():
{code:java}
public static long getMinTimestampForDiff(@NotNull RevisionVector fromRev,
@NotNull RevisionVector toRev,
@NotNull RevisionVector
minRevisions) {
// make sure we have minimum revisions for all known cluster nodes
fromRev = fromRev.pmax(minRevisions);
toRev = toRev.pmax(minRevisions);
// keep only revision entries that changed
RevisionVector from = fromRev.difference(toRev);
RevisionVector to = toRev.difference(fromRev);
// now calculate minimum timestamp
long min = Long.MAX_VALUE;
for (Revision r : from) {
min = Math.min(r.getTimestamp(), min);
}
for (Revision r : to) {
min = Math.min(r.getTimestamp(), min);
}
return min;
}
{code}
where the minRevisions is derived from the start time of the *external* cluster
nodes.
So the statement
{code}
fromRev = fromRev.pmax(minRevisions);
{code}
may yield a revision which is newer than the original starting point of the
diff, apparently assuming that external cluster nodes have synced after
startup. The internal cluster node is excluded, because it might have been
restarted after the timestamp corresponding to the original fromRevision.
In readonly mode, the DocumentNodeStore has cluster id 0, so all cluster nodes
are considered external and the exclusion is not working.
Since we don't even know which cluster node is the one to exclude, I think that
we have to use the parallel minimum instead of the parallel maximum in this
case.
See attached PR#1465 for a unit test and a fix proposal.
cc [~stefanegli]
> DocumentNodeStore#diffManyChildren(...) may produce incorrect results in
> readonly mode
> --------------------------------------------------------------------------------------
>
> Key: OAK-10812
> URL: https://issues.apache.org/jira/browse/OAK-10812
> Project: Jackrabbit Oak
> Issue Type: Bug
> Components: documentmk
> Reporter: Manfred Baedke
> Assignee: Manfred Baedke
> Priority: Major
>
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