Index: src/test/java/org/apache/jackrabbit/oak/plugins/segment/file/CompactionAndCleanupTest.java
===================================================================
--- src/test/java/org/apache/jackrabbit/oak/plugins/segment/file/CompactionAndCleanupTest.java	(revision 1631964)
+++ src/test/java/org/apache/jackrabbit/oak/plugins/segment/file/CompactionAndCleanupTest.java	(working copy)
@@ -22,14 +22,21 @@
 import java.io.ByteArrayInputStream;
 import java.io.File;
 import java.io.IOException;
+import java.util.HashSet;
 import java.util.Random;
+import java.util.Set;
+import java.util.UUID;
 
 import org.apache.commons.io.FileUtils;
 import org.apache.jackrabbit.oak.api.Blob;
 import org.apache.jackrabbit.oak.plugins.segment.Compactor;
+import org.apache.jackrabbit.oak.plugins.segment.SegmentId;
+import org.apache.jackrabbit.oak.plugins.segment.SegmentNodeState;
 import org.apache.jackrabbit.oak.plugins.segment.SegmentNodeStore;
+import org.apache.jackrabbit.oak.plugins.segment.SegmentWriter;
 import org.apache.jackrabbit.oak.spi.commit.CommitInfo;
 import org.apache.jackrabbit.oak.spi.commit.EmptyHook;
+import org.apache.jackrabbit.oak.spi.state.ChildNodeEntry;
 import org.apache.jackrabbit.oak.spi.state.NodeBuilder;
 import org.apache.jackrabbit.oak.spi.state.NodeState;
 import org.apache.jackrabbit.oak.spi.state.NodeStore;
@@ -38,8 +45,10 @@
 import org.junit.Ignore;
 import org.junit.Test;
 
+import static org.apache.jackrabbit.oak.plugins.memory.EmptyNodeState.EMPTY_NODE;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.assertFalse;
 
 public class CompactionAndCleanupTest {
 
@@ -180,4 +189,65 @@
         }
     }
 
+    // OAK-2192
+    @Test
+    public void testMixedSegments() throws Exception {
+        FileStore store = new FileStore(directory, 2, false);
+        SegmentNodeStore nodeStore = new SegmentNodeStore(store);
+
+        // Create some content
+        NodeBuilder builder = nodeStore.getRoot().builder();
+        builder.child("c1").setProperty("a", "foo");
+        nodeStore.merge(builder, EmptyHook.INSTANCE, CommitInfo.EMPTY);
+
+        Set<UUID> beforeSegments = new HashSet<UUID>();
+        collectSegments(store.getHead(), beforeSegments);
+
+        //
+        // a copy of FileStore#compact
+        //
+        SegmentWriter writer = new SegmentWriter(store, store.getTracker());
+        Compactor compactor = new Compactor(writer);
+
+        SegmentNodeState before = store.getHead();
+        SegmentNodeState after = compactor.compact(EMPTY_NODE, before);
+        writer.flush();
+
+        // -- manually adding some content, a poor man's concurrent change simulation
+        builder = nodeStore.getRoot().builder();
+        builder.child("c2").setProperty("a", "bar");
+        nodeStore.merge(builder, EmptyHook.INSTANCE, CommitInfo.EMPTY);
+        //
+
+        while (!store.setHead(before, after)) {
+            // Some other concurrent changes have been made.
+            // Rebase (and compact) those changes on top of the
+            // compacted state before retrying to set the head.
+            SegmentNodeState head = store.getHead();
+            after = compactor.compact(before, head);
+            before = head;
+            writer.flush();
+        }
+
+        Set<UUID> afterSegments = new HashSet<UUID>();
+        collectSegments(store.getHead(), afterSegments);
+        try {
+            for (UUID u : beforeSegments) {
+                assertFalse("Mixed segments found", afterSegments.contains(u));
+            }
+        } finally {
+            store.close();
+        }
+    }
+
+    private void collectSegments(SegmentNodeState s, Set<UUID> segmentIds) {
+        SegmentId sid = s.getRecordId().getSegmentId();
+        UUID id = new UUID(sid.getMostSignificantBits(),
+                sid.getLeastSignificantBits());
+        segmentIds.add(id);
+        for (ChildNodeEntry cne : s.getChildNodeEntries()) {
+            collectSegments((SegmentNodeState) cne.getNodeState(), segmentIds);
+        }
+    }
+
 }