[jira] [Comment Edited] (OAK-4321) Improve conflict exception message to show if conflict is unexpected

["Marcel Reutegger (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/OAK-4321?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15277870#comment-15277870 ] 

Marcel Reutegger edited comment on OAK-4321 at 5/11/16 7:29 AM:
----------------------------------------------------------------

The check is not quite correct, it will report that a revision is older than the base revision vector when it is actually equal. I think the patch should look like this:

{noformat}
--- a/oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/document/Commit.java
+++ b/oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/document/Commit.java
@@ -42,6 +42,7 @@ import org.apache.jackrabbit.oak.spi.state.NodeState;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import static com.google.common.base.Objects.equal;
 import static com.google.common.base.Preconditions.checkNotNull;
 import static com.google.common.collect.Iterables.filter;
 import static com.google.common.collect.Iterables.transform;
@@ -565,6 +566,10 @@ public class Commit {
     private String formatConflictRevision(Revision r) {
         if (nodeStore.getHeadRevision().isRevisionNewer(r)) {
             return r + " (not yet visible)";
+        } else if (baseRevision != null
+                && !baseRevision.isRevisionNewer(r)
+                && !equal(baseRevision.getRevision(r.getClusterId()), r)) {
+            return r + " (older than base " + baseRevision + ")";
         } else {
             return r.toString();
         }
{noformat}


was (Author: mreutegg):
The check is not quite correct, it will report that a revision is older than the base revision vector when it is actually equal. I think the patch should look like this:

{noformat}
--- a/oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/document/Commit.java
+++ b/oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/document/Commit.java
@@ -42,6 +42,7 @@ import org.apache.jackrabbit.oak.spi.state.NodeState;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import static com.google.common.base.Objects.equal;
 import static com.google.common.base.Preconditions.checkNotNull;
 import static com.google.common.collect.Iterables.filter;
 import static com.google.common.collect.Iterables.transform;
@@ -565,6 +566,10 @@ public class Commit {
     private String formatConflictRevision(Revision r) {
         if (nodeStore.getHeadRevision().isRevisionNewer(r)) {
             return r + " (not yet visible)";
+        } else if (baseRevision != null
+                && !baseRevision.isRevisionNewer(r)
+                && !equal(baseRevision.getRevision(r.getClusterId()), r)) {
+            return r + " (older than base - " + baseRevision + ")";
         } else {
             return r.toString();
         }
{noformat}

> Improve conflict exception message to show if conflict is unexpected
> --------------------------------------------------------------------
>
>                 Key: OAK-4321
>                 URL: https://issues.apache.org/jira/browse/OAK-4321
>             Project: Jackrabbit Oak
>          Issue Type: Improvement
>          Components: core, documentmk
>            Reporter: Vikas Saurabh
>            Assignee: Marcel Reutegger
>            Priority: Minor
>             Fix For: 1.6, 1.5.2, 1.0.31, 1.2.15, 1.4.3
>
>         Attachments: OAK-4321-1.0.diff
>
>
> Merge exception (aka OakMergeXXXX) are often expected when concurrent sessions do conflicting writes. But in some occasions, we've seen bugs in oak which also lead to merge exception.
> This creates confusion during investigation to isolate if it's an issue in oak or a genuine concurrent conflict.
> It'd be useful if the exception message has information to distinguish that.



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