Merges several ranked lists (for example, one per worker partition) into one ranked list, keeping at most topK rows (null keeps all). Ties are broken by ascending row so partitioning never changes the result.
topK
null
Merges several ranked lists (for example, one per worker partition) into one ranked list, keeping at most
topKrows (nullkeeps all). Ties are broken by ascending row so partitioning never changes the result.