stefan-egli commented on code in PR #1779:
URL: https://github.com/apache/jackrabbit-oak/pull/1779#discussion_r1829546975
##########
oak-store-document/src/test/java/org/apache/jackrabbit/oak/plugins/document/DocumentNodeStoreIT.java:
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@@ -188,6 +196,255 @@ public void blockingBlob() throws Exception {
}
}
+ /**
+ * OAK-11184 : a cluster node A is merging a change on root. That involves
two
+ * updates : the first one writing the changes. The second one updating the
+ * commit root (with a revisions=c). If a cluster node B reads the root
while
+ * the commit root was not yet updated, it has to read previous documents
as
+ * part resolving the value of a property in getNodeAtRevision. Only to
find
+ * that the new property does not exist in any previous document and is
thus
+ * non-existent. Cluster node B will have to repeat going through
+ * previous documents whenever reading root - until B is
+ * able to do a backgroundRead. The backgroundRead however could be
blocked by a
+ * number of merge operations - as those merge operations acquire the
+ * backgroundOperationLock - and backgroundRead wants that lock
exclusively.
+ *
+ * The test reproduces only part one of the above (expensiveness of reading
+ * not-yet-visible property of a document with many previous documents).
+ */
+ @Test
+ public void unmergedCommitOnRoot_withPrevNoPropCache() throws Exception {
+ doUnmergedCommitOnRoot(true);
+ }
+
+ /**
+ * This variant tests without the case and is thus expected to fail with
+ * an AssertionError
+ */
+ @Test(expected = AssertionError.class)
+ public void unmergedCommitOnRoot_withoutPrevNoPropCache() throws Exception
{
+ doUnmergedCommitOnRoot(false);
+ }
+
+ private void doUnmergedCommitOnRoot(boolean prevNoPropCacheEnabled) throws
Exception {
+ Clock clock = new Clock.Virtual();
+ clock.waitUntil(System.currentTimeMillis());
+ Revision.setClock(clock);
+ ClusterNodeInfo.setClock(clock);
+
+ FailingDocumentStore fs1 = new FailingDocumentStore(ds);
+ PausableDocumentStore store1 = new PausableDocumentStore(fs1);
+ DocumentNodeStore ns1 =
builderProvider.newBuilder().setClusterId(1).setAsyncDelay(0).clock(clock)
+
.setPrevNoPropCacheFeature(createFeature(prevNoPropCacheEnabled))
+ .setDocumentStore(store1).build();
+
+ NodeBuilder b1 = ns1.getRoot().builder();
+ b1.setProperty("prop", -1);
+ ns1.merge(b1, EmptyHook.INSTANCE, CommitInfo.EMPTY);
+
+ // create MANY previous docs
+ System.out.println(new Date() + " - creating MANY previous docs...");
Review Comment:
don't like system outs? :)
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