svn commit: r1711654 - /jackrabbit/oak/trunk/oak-core/src/main/java/org/apache/jackrabbit/oak/spi/commit/BackgroundObserver.java

[md...@apache.org]

Author: mduerig
Date: Sat Oct 31 16:44:09 2015
New Revision: 1711654

URL: http://svn.apache.org/viewvc?rev=1711654&view=rev
Log:
OAK-3372: Collapsing external events in BackgroundObserver even before queue is full leads to JournalEntry not getting used
Make *not* collapsing external events the default. Credits to Vikas Saurabh for the patch.

Modified:
    jackrabbit/oak/trunk/oak-core/src/main/java/org/apache/jackrabbit/oak/spi/commit/BackgroundObserver.java

Modified: jackrabbit/oak/trunk/oak-core/src/main/java/org/apache/jackrabbit/oak/spi/commit/BackgroundObserver.java
URL: http://svn.apache.org/viewvc/jackrabbit/oak/trunk/oak-core/src/main/java/org/apache/jackrabbit/oak/spi/commit/BackgroundObserver.java?rev=1711654&r1=1711653&r2=1711654&view=diff
==============================================================================
--- jackrabbit/oak/trunk/oak-core/src/main/java/org/apache/jackrabbit/oak/spi/commit/BackgroundObserver.java (original)
+++ jackrabbit/oak/trunk/oak-core/src/main/java/org/apache/jackrabbit/oak/spi/commit/BackgroundObserver.java Sat Oct 31 16:44:09 2015
@@ -49,8 +49,9 @@ import org.slf4j.LoggerFactory;
  * to fill up, any further update will automatically be merged into just one
  * external content change, causing potential loss of local commit information.
  * To help prevent such cases, any sequential external content changes that
- * the background observer thread has yet to process are automatically merged
- * to just one change.
+ * the background observer thread has yet to process are optionally
+ * (see {@code alwaysCollapseExternalEvents} and {@code oak.observation.alwaysCollapseExternal})
+ * automatically merged to just one change.
  */
 public class BackgroundObserver implements Observer, Closeable {
 
@@ -84,6 +85,12 @@ public class BackgroundObserver implemen
      */
     private final int maxQueueLength;
 
+    /**
+     * Whether external events should be collapsed even if queue isn't full yet.
+     */
+    private final boolean alwaysCollapseExternalEvents =
+            Boolean.parseBoolean(System.getProperty("oak.observation.alwaysCollapseExternal", "false"));
+
     private static class ContentChange {
         private final NodeState root;
         private final CommitInfo info;
@@ -254,7 +261,7 @@ public class BackgroundObserver implemen
         checkState(!stopped);
         checkNotNull(root);
 
-        if (info == null && last != null && last.info == null) {
+        if (alwaysCollapseExternalEvents && info == null && last != null && last.info == null) {
             // This is an external change. If the previous change was
             // also external, we can drop it from the queue (since external
             // changes in any case can cover multiple commits) to help