When intra-merge parallelism was introduced, the validation that numWorkers must ==1 with a null executor service was removed from Lucene99HnswVectorsFormat. However, I forgot to remove that validation from Lucene99HnswScalarQuantizedVectorsFormat.
This corrects that mistake, allowing Lucene99HnswScalarQuantizedVectorsFormat and Lucene99HnswVectorsFormat to take advantage of the merge-schedulers intra-merge threading.
When intra-merge parallelism was introduced, the validation that
numWorkersmust==1with anullexecutor service was removed fromLucene99HnswVectorsFormat. However, I forgot to remove that validation fromLucene99HnswScalarQuantizedVectorsFormat.This corrects that mistake, allowing
Lucene99HnswScalarQuantizedVectorsFormatandLucene99HnswVectorsFormatto take advantage of the merge-schedulers intra-merge threading.