For larger volumes of indexing and when faster indexing performance is crucial, increase the maximum size for index insertion batches. Index insertion batches contain index requests that are added to the index request queue.
Index requests are added to the queue in batches only for the requests that are not created automatically. Changing insertion batch size only affects the index requests that are created as the result of the index jobs that you submit.
-DCBRMaxRowsInBatch=x
The symbol x represents the size.