[OAI-implementers] Flow Control chunk size

Ann Apps ann.apps at manchester.ac.uk
Fri Feb 2 07:00:31 EST 2007

Hi All,

The OAI-PMH spec section 3.5 Flow Control details how to respond to list requests in installments with a resumptionToken. The reason for this partitioning is that lists may be long from a large database. A couple of questions:

1. Are there any guidelines on best practice for what to choose as a chunk size? I guess this question is really asking what size of data package is it reasonable to send over HTTP. 

I currently have a chunk size of 25, some records in a specific XML metadata format being quite long. Someone recently asked me why we supply records 25 at a time, and I do not really have an answer.

2. Is it permissible to have a different chunk size for ListIdentifiers and ListRecords? The former will be a much shorter response than the latter. Also can one have a different chunk size for ListRecords in different metadata formats?

>From the spec this looks to be OK - all the details are contained in the resumptionToken and its XML attributes. But I don't want to implement something that is invalid.

Thanks for any advice.
Best wishes,

Ann Apps. IT Specialist (Research & Development), MIMAS,
   The University of Manchester, Oxford Road, Manchester, M13 9PL, UK 
Tel: +44 (0) 161 275 6039  Fax: +44 (0) 161 275 6040
Email: ann.apps at manchester.ac.uk WWW: http://epub.mimas.ac.uk/ann.html

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