presto-main/src/main/java/io/prestosql/operator/LookupJoinOperator.java/JoinProcessor/needsInput
class JoinProcessor:        private boolean needsInput()
        {
            return !finishing
                    && lookupSourceProviderFuture.isDone()
                    && spillInProgress.isDone()
                    && probe == null
                    && outputPage == null;
        }