Index: src/main/java/org/apache/jackrabbit/oak/plugins/segment/Compactor.java
===================================================================
--- src/main/java/org/apache/jackrabbit/oak/plugins/segment/Compactor.java	(revision 1701615)
+++ src/main/java/org/apache/jackrabbit/oak/plugins/segment/Compactor.java	(working copy)
@@ -65,6 +65,8 @@
 
     private final PartialCompactionMap map;
 
+    private final ProgressTracker progress = new ProgressTracker();
+
     /**
      * Map from {@link #getBlobKey(Blob) blob keys} to matching compacted
      * blob record identifiers. Used to de-duplicate copies of the same
@@ -111,8 +113,10 @@
      * @return  the compacted state
      */
     public SegmentNodeState compact(NodeState before, NodeState after) {
+        progress.start();
         SegmentNodeState compacted = process(before, after, before).getNodeState();
         writer.flush();
+        progress.stop();
         return compacted;
     }
 
@@ -125,8 +129,10 @@
      * @return  the compacted state
      */
     public SegmentNodeState compact(NodeState before, NodeState after, NodeState onto) {
+        progress.start();
         SegmentNodeState compacted = process(before, after, onto).getNodeState();
         writer.flush();
+        progress.stop();
         return compacted;
     }
 
@@ -167,6 +173,7 @@
             if (path != null) {
                 log.trace("propertyAdded {}/{}", path, after.getName());
             }
+            progress.onProperty();
             return super.propertyAdded(compact(after));
         }
 
@@ -175,6 +182,7 @@
             if (path != null) {
                 log.trace("propertyChanged {}/{}", path, after.getName());
             }
+            progress.onProperty();
             return super.propertyChanged(before, compact(after));
         }
 
@@ -183,6 +191,7 @@
             if (path != null) {
                 log.trace("childNodeAdded {}/{}", path, name);
             }
+            progress.onNode();
             RecordId id = null;
             if (after instanceof SegmentNodeState) {
                 id = ((SegmentNodeState) after).getRecordId();
@@ -214,6 +223,7 @@
             if (path != null) {
                 log.trace("childNodeChanged {}/{}", path, name);
             }
+            progress.onNode();
 
             RecordId id = null;
             if (after instanceof SegmentNodeState) {
@@ -269,7 +279,7 @@
     private Blob compact(Blob blob) {
         if (blob instanceof SegmentBlob) {
             SegmentBlob sb = (SegmentBlob) blob;
-
+            progress.onBinary();
             try {
                 // else check if we've already cloned this specific record
                 RecordId id = sb.getRecordId();
@@ -328,4 +338,54 @@
         }
     }
 
+    private class ProgressTracker {
+
+        private final int logAt = Integer.getInteger("compaction-progress-log",
+                15000);
+
+        private long start = 0;
+
+        private long nodes = 0;
+        private long properties = 0;
+        private long binaries = 0;
+
+        void start() {
+            nodes = 0;
+            properties = 0;
+            binaries = 0;
+            start = System.currentTimeMillis();
+        }
+
+        void onNode() {
+            if (++nodes % logAt == 0) {
+                logProgress(start, false);
+                start = System.currentTimeMillis();
+            }
+        }
+
+        void onProperty() {
+            properties++;
+        }
+
+        void onBinary() {
+            binaries++;
+        }
+
+        void stop() {
+            logProgress(start, true);
+        }
+
+        private void logProgress(long start, boolean done) {
+            log.debug(
+                    "Compacted {} nodes, {} properties, {} binaries in {} ms.",
+                    nodes, properties, binaries, System.currentTimeMillis()
+                            - start);
+            if (done) {
+                log.info(
+                        "Finished compaction: {} nodes, {} properties, {} binaries.",
+                        nodes, properties, binaries);
+            }
+        }
+    }
+
 }