[OAI-implementers] ListRecords request w/out an until..

Simeon Warner simeon.warner at cornell.edu
Tue Feb 1 10:05:24 EST 2011

Hi Ben,

This is covered in the in section 3.5.1 of the specification:


I think your solution for the harvester is the correct one. Provided the 
harvester starts again with from=t0 all changes between t0 and t2 will be 
harvested, irrespective of whether or not they were included in the original 
response (modulo understood problems with items that move between sets for set 
selective requests).


On 02/01/2011 09:09 AM, Benjamin Anderson wrote:
> Hi,
> I'm wondering what others are doing when a ListRecords request w/out an
> until comes in.� Consider this scenario:
> t0 - harvest request (with no until) is initiated
> t1 - record 101 is added to the repo
> t2 - harvest is finished (it took multiple requests to complete)
> Should record 101 be included in the harvest data?� If not, will the
> client better issue their next harvest with a from=t0 (a from=t2 would
> be invalid because they'd miss out on record 101).
> We have implemented both oai-pmh harvesters and providers, so I have to
> consider both ends of this.� Here's what I'm thinking...
> As a Provider
> I will simply lock the repo so that the above scenario can't happen.� If
> someone is already harvesting (there exist unexpired resumptionTokens)
> then I will not update the repository.
> As a Harvester
> I will always use the until parameter with the value of the time the
> harvest was initially started.
> I think this keeps me clear of any problems.� Anyone else have thoughts
> or care to share your solutions?
> Thanks,
> Ben Anderson
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