Solr always requires to limit the search results. This default value will be set if the Search API query itself is not limited. 2147483630 is the theoretical maximum since the result pointer is an integer. But be careful! Especially in Solr Cloud setups too high values might cause an OutOfMemoryException because Solr reserves this rows limit per shard for sorting the combined result. This sum must not exceed the maximum integer value! And even if there is no exception any too high memory consumption per query on your server is a bad thing in general.