Snapshot not working in RocksDB Java

We are using rocksdbjni version 9.0.0. We have a usecase where we need to scan for some keys from one column family say CF-1. Let's say prefix scanning from CF-1 resulted in 10 keys. Now in the same method, we goto another column family CF-2 for fetching the value associated with each keys we fetched earlier.

The problem is while we goto CF-2 with a bunch of keys, some other thread invalidates those keys and removes their entries from CF-2. This is causing us problem. I was hoping to take a snapshot of the db and then do perform the read operations and release the snapshot. Apparently this is not helping. Pseudo code is below

public List getOrderDataForUser(String userId) { Transaction transaction = db.beginTransaction(new WriteOptions()); ThreadLocal threadLocal = new ThreadLocal<>(); threadLocal.set(transaction.getSnapshot()); ReadOptions ro = new ReadOptions(); ro.setSnapshot(threadLocal.get());

         var iterator = transaction.getIterator(ro, columnFamilyHandle);
     List<String> keys = getKeysForPrefix(userId, iterator); // some function that does prefix scanning and returns the matching keys
     //next - go to CF-2 and fetch order data for the keys

List<StoredOrder> orderDataList = transaction.multiGetAsList(defaultReadOptions, cfs, keys)
    .stream()
    .map(this::safeDeserialize)
    .filter(Objects::nonNull)
    .collect(Collectors.toList());
transaction.clearSnapshot();

return orderDataList; }

Expected behavior

snapshot secures a version of db at that point in time, so that deletion by other threads do not disturb the read operations

Actual behavior

snapshot doesn't work. When we goto CF-2 for fetching the value associated with some keys, we notice that some other threads have modified the data

Steps to reproduce the behavior

create a column family add some key value pairs begin a transaction and take a snapshot read value associated with each keys in a loop make another thread delete of the keys

we can see that data in our snapshot is also modified

facebook / rocksdb