diff --git a/include/rocksdb/utilities/write_batch_with_index.h b/include/rocksdb/utilities/write_batch_with_index.h
index e79f5985f..ba2029674 100644
--- a/include/rocksdb/utilities/write_batch_with_index.h
+++ b/include/rocksdb/utilities/write_batch_with_index.h
@@ -155,6 +155,12 @@ class WriteBatchWithIndex : public WriteBatchBase {
   // The returned iterator should be deleted by the caller.
   // The base_iterator is now 'owned' by the returned iterator. Deleting the
   // returned iterator will also delete the base_iterator.
+  //
+  // Updating write batch with the current key of the iterator is not safe.
+  // We strongly recommand users not to do it. It will invalidate the current
+  // key() and value() of the iterator. This invalidation happens even before
+  // the write batch update finishes. The state may recover after Next() is
+  // called.
   Iterator* NewIteratorWithBase(ColumnFamilyHandle* column_family,
                                 Iterator* base_iterator);
   // default column family
diff --git a/java/src/main/java/org/rocksdb/WriteBatchWithIndex.java b/java/src/main/java/org/rocksdb/WriteBatchWithIndex.java
index dc6b0ba60..2c0350837 100644
--- a/java/src/main/java/org/rocksdb/WriteBatchWithIndex.java
+++ b/java/src/main/java/org/rocksdb/WriteBatchWithIndex.java
@@ -114,6 +114,12 @@ public class WriteBatchWithIndex extends AbstractWriteBatch {
    * creating a new Iterator that will use {@link org.rocksdb.WBWIRocksIterator}
    * as a delta and baseIterator as a base
    *
+   * Updating write batch with the current key of the iterator is not safe.
+   * We strongly recommand users not to do it. It will invalidate the current
+   * key() and value() of the iterator. This invalidation happens even before
+   * the write batch update finishes. The state may recover after Next() is
+   * called.
+   *
    * @param columnFamilyHandle The column family to iterate over
    * @param baseIterator The base iterator,
    *   e.g. {@link org.rocksdb.RocksDB#newIterator()}