azagrebin commented on a change in pull request #6638: [FLINK-10267][State] Fix 
arbitrary iterator access on RocksDBMapIterator
URL: https://github.com/apache/flink/pull/6638#discussion_r214344987
 
 

 ##########
 File path: 
flink-state-backends/flink-statebackend-rocksdb/src/main/java/org/apache/flink/contrib/streaming/state/RocksDBMapState.java
 ##########
 @@ -595,6 +595,8 @@ private void loadCache() {
                                 */
                                if (lastEntry != null && !lastEntry.deleted) {
                                        iterator.next();
+                                       cacheEntries.add(lastEntry);
+                                       cacheIndex = 1;
 
 Review comment:
   Could be also just:
   ```
   if (lastEntry != null && !lastEntry.deleted) {
       cacheIndex = 1;
   }
   ```
   
   This should work in general. I wonder if we could make it cleaner.
   Although, the remove operation is not supposed to be called twice for the 
same next,
   if it happens and `lastEntry.deleted` is true, the problem will stay.
   What if we cache always the previously returned value in `nextEntry()` as a 
class field:
   ```
   previousEntry = cacheEntries.get(cacheIndex);
   ```
   then remove could be:
   ```
           @Override
                public void remove() {
                        if (previousEntry == null) {
                                throw new IllegalStateException("The remove 
operation must be called after a valid next operation.");
                        }
   
                        if (!previousEntry.deleted) {
                            previousEntry.remove();
               }
                }
   ```
   
   What do you think?

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