Github user StefanRRichter commented on a diff in the pull request: https://github.com/apache/flink/pull/5518#discussion_r169076426 --- Diff: flink-contrib/flink-statebackend-rocksdb/src/main/java/org/apache/flink/contrib/streaming/state/RocksDBKeyedStateBackend.java --- @@ -1991,43 +1999,71 @@ public int numStateEntries() { return count; } + /** + * This class is not thread safety. + */ private static class RocksIteratorWrapper<K> implements Iterator<K> { private final RocksIterator iterator; private final String state; private final TypeSerializer<K> keySerializer; private final int keyGroupPrefixBytes; + private final byte[] namespaceBytes; + private K nextKey; public RocksIteratorWrapper( RocksIterator iterator, String state, TypeSerializer<K> keySerializer, - int keyGroupPrefixBytes) { + int keyGroupPrefixBytes, + byte[] namespaceBytes) { this.iterator = Preconditions.checkNotNull(iterator); this.state = Preconditions.checkNotNull(state); this.keySerializer = Preconditions.checkNotNull(keySerializer); this.keyGroupPrefixBytes = Preconditions.checkNotNull(keyGroupPrefixBytes); + this.namespaceBytes = Preconditions.checkNotNull(namespaceBytes); + this.nextKey = null; } @Override public boolean hasNext() { - return iterator.isValid(); + final int namespaceBytesLength = namespaceBytes.length; + while (nextKey == null && iterator.isValid()) { + try { + boolean namespaceValid = true; + byte[] key = iterator.key(); + if (key.length >= namespaceBytesLength + keyGroupPrefixBytes) { --- End diff -- We could decompose this loop by introducing a helper method `isMatchingNameSpace(byte[] key, byte[] nameSpaceBytes)`. I think that makes the control flow easier to read.
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