diff --git a/oak-core/src/main/java/org/apache/jackrabbit/oak/query/QueryImpl.java b/oak-core/src/main/java/org/apache/jackrabbit/oak/query/QueryImpl.java
index 3f08b4fae4e..f951bfb7718 100644
--- a/oak-core/src/main/java/org/apache/jackrabbit/oak/query/QueryImpl.java
+++ b/oak-core/src/main/java/org/apache/jackrabbit/oak/query/QueryImpl.java
@@ -14,6 +14,10 @@
 package org.apache.jackrabbit.oak.query;
 
 import static java.util.Objects.requireNonNull;
+import static org.apache.jackrabbit.JcrConstants.JCR_PRIMARYTYPE;
+import static org.apache.jackrabbit.oak.plugins.index.IndexConstants.INDEX_DEFINITIONS_NAME;
+import static org.apache.jackrabbit.oak.plugins.index.IndexConstants.INDEX_DEFINITIONS_NODE_TYPE;
+import static org.apache.jackrabbit.oak.plugins.index.IndexConstants.REINDEX_PROPERTY_NAME;
 import static org.apache.jackrabbit.oak.query.ast.AstElementFactory.copyElementAndCheckReference;
 
 import java.math.BigInteger;
@@ -32,9 +36,11 @@
 import java.util.stream.Collectors;
 
 import org.apache.commons.lang3.StringUtils;
+import org.apache.jackrabbit.oak.api.PropertyState;
 import org.apache.jackrabbit.oak.api.PropertyValue;
 import org.apache.jackrabbit.oak.api.Result.SizePrecision;
 import org.apache.jackrabbit.oak.api.Tree;
+import org.apache.jackrabbit.oak.api.Type;
 import org.apache.jackrabbit.oak.namepath.JcrPathParser;
 import org.apache.jackrabbit.oak.namepath.NamePathMapper;
 import org.apache.jackrabbit.oak.plugins.index.IndexUtils;
@@ -1267,6 +1273,26 @@ public void verifyNotPotentiallySlow() {
             }
             String caller = IndexUtils.getCaller(settings.getIgnoredClassNamesInCallTrace());
             String message = "Traversal query (query without index): " + statement + "; called by " + caller + "; consider creating an index";
+            if (traversal == Traversal.FAIL || traversal == Traversal.WARN && !potentiallySlowTraversalQueryLogged) {
+                HashSet<String> reindex = new HashSet<>();
+                Iterable<Tree> indexes = context.getRoot().getTree("/" + INDEX_DEFINITIONS_NAME).getChildren();
+                for (Tree index : indexes) {
+                    String name = index.getName();
+                    PropertyState primaryType = index.getProperty(JCR_PRIMARYTYPE);
+                    if (primaryType != null && INDEX_DEFINITIONS_NODE_TYPE.equals(primaryType.getValue(Type.STRING))) {
+                        PropertyState reindexProp = index.getProperty(REINDEX_PROPERTY_NAME);
+                        if (reindexProp != null && reindexProp.getValue(Type.BOOLEAN)) {
+                            reindex.add(name);
+                        }
+                    }
+                }
+                message += "\n\nExecution plan:\n" + getPlan();
+                if (!reindex.isEmpty()) {
+                    String reindexNames = reindex.stream().map(name -> name + ",").collect(Collectors.joining());
+                    message += "\n\nNote that the following indexes were unavailable because of re-indexing:\n"
+                        + reindexNames.substring(0, reindexNames.length() - 1);
+                }
+            }
             switch (traversal) {
             case DEFAULT:
                 // not possible (changed to either FAIL or WARN above)
diff --git a/oak-jcr/src/test/java/org/apache/jackrabbit/oak/jcr/query/QueryTest.java b/oak-jcr/src/test/java/org/apache/jackrabbit/oak/jcr/query/QueryTest.java
index 04b383957c9..e8d7e154e85 100644
--- a/oak-jcr/src/test/java/org/apache/jackrabbit/oak/jcr/query/QueryTest.java
+++ b/oak-jcr/src/test/java/org/apache/jackrabbit/oak/jcr/query/QueryTest.java
@@ -18,6 +18,10 @@
  */
 package org.apache.jackrabbit.oak.jcr.query;
 
+import static org.apache.jackrabbit.oak.plugins.index.IndexConstants.INDEX_DEFINITIONS_NAME;
+import static org.apache.jackrabbit.oak.plugins.index.IndexConstants.REINDEX_PROPERTY_NAME;
+import static org.apache.jackrabbit.oak.plugins.index.IndexUtils.createIndexDefinition;
+import static org.apache.jackrabbit.oak.spi.commit.CommitInfo.EMPTY;
 import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.Assert.assertEquals;
@@ -41,6 +45,7 @@
 import javax.jcr.RepositoryException;
 import javax.jcr.Session;
 import javax.jcr.ValueFactory;
+import javax.jcr.Workspace;
 import javax.jcr.nodetype.NodeTypeManager;
 import javax.jcr.query.InvalidQueryException;
 import javax.jcr.query.Query;
@@ -60,6 +65,8 @@
 import org.apache.jackrabbit.oak.commons.json.JsopTokenizer;
 import org.apache.jackrabbit.oak.fixture.NodeStoreFixture;
 import org.apache.jackrabbit.oak.jcr.AbstractRepositoryTest;
+import org.apache.jackrabbit.oak.spi.commit.EmptyHook;
+import org.apache.jackrabbit.oak.spi.state.NodeBuilder;
 import org.junit.Ignore;
 import org.junit.Test;
 
@@ -138,6 +145,37 @@ public void testSettingsOverride() throws Exception {
         assertEquals(90, count);
     }
 
+    @Test
+    public void traversalExtendedDiagnosis() throws Exception {
+        Session session = getAdminSession();
+        Workspace workspace = session.getWorkspace();
+        NodeBuilder rootBuilder = getNodeStore().getRoot().builder();
+        createIndexDefinition(
+                rootBuilder.child(INDEX_DEFINITIONS_NAME), "foo", true, false,
+                Set.of("foo"), null);
+        getNodeStore().merge(rootBuilder, EmptyHook.INSTANCE, EMPTY);
+        session.refresh(true);
+        rootBuilder.child("a").setProperty("foo", "abc");
+        //set reindex=true without a CommitHook to simulate an ongoing re-indexing process.
+        rootBuilder.child(INDEX_DEFINITIONS_NAME).child("foo").setProperty(REINDEX_PROPERTY_NAME, true);
+        getNodeStore().merge(rootBuilder, EmptyHook.INSTANCE, EMPTY);
+        session.refresh(true);
+        Node foo = session.getNode("/" + INDEX_DEFINITIONS_NAME).getNode("foo");
+        assertTrue(foo.getProperty(REINDEX_PROPERTY_NAME).getBoolean());
+        Query query = workspace.getQueryManager().createQuery("select * from [nt:base] where [x] = 1 or [y] = 2 option(traversal fail)", Query.JCR_SQL2);
+        try {
+            query.execute();
+            fail("traversing query should not succeed");
+        } catch (RepositoryException e) {
+            String message = e.getMessage();
+            assertTrue(message.contains("Traversal query (query without index)"));
+            assertTrue(message.contains("Execution plan"));
+            assertTrue(message.contains("[nt:base] as [nt:base] /* traverse"));
+            assertTrue(message.contains("Note that the following indexes were unavailable because of re-indexing"));
+            assertTrue(message.contains("foo"));
+        }
+    }
+
     @Test
     public void traversalOption() throws Exception {
         Session session = getAdminSession();