calling xquery on an accessor with a quantity parameter

hello all,

i am working with tamino 4.2.1 and trying to setup a java client.
i have a large collection containing 272201 xml docs and a large schema. I have build some indexes on the fields i need, to speed up the queries. Reading the documentation, i have noticed that i could use a quantity parameter to make tamino search the documents by batches (TXMLObjectAccessor.xquery(xquery, int quantity) ). I had the idea to use it because it will not be rare that the queries i make return several thousands of documents.
I don’t really understand if this paramater speeds up the document retrieval (and helps avoiding the time out errors), or if it helps avoiding the “outofmemory” errors in segmenting the load or both (or none).
Could someone give me more detail on this ?
thanks in advance