Indeed the ultimate truth source is on the wikidata site it self. However, I am not aware of a way to query the Wikidata site for a list of items fitting a certain condition (e.g. all Wikidata items containing a claim with the NCBI Entrez Gene (P351) property.)

It is here that I need to rely on WDQ (and WDQS) and potentially risk missing existing items due to delays in which WDQ (and WDAS) gets updated.

I would like to know if I could rely on a given time frame - being it seconds, hours, days, or one week).

I currently assume a delay of a week, but I don't know how accurate this assumption is.

Regards,

On Thu, Jun 18, 2015 at 10:23 PM, Stas Malyshev <smalyshev@wikimedia.org> wrote:

Hi!

> The way that updates work *in all systems* (polling small lists of
> recent changes at intervals and hoping that this leads to a complete
> change history), it seems quite possible that such systems will
> sometimes miss an update, at least in the long run and under varying
> conditions (high server load, network troubles, update script down for a
> while, whatever). Insufficient update frequency is maybe not the biggest
> problem here (it should be in the range of one to a few minutes for all
> of the services).

Very important point with which I agree - it is completely possible that
update polling misses an update, WDQS is no exception and it usually
does not treat it as a problem, as the next update can fill up the
missed one. However the ultimate truth source is on the wikidata site
only. Beware of the caches though - if you ask for the same data on the
same URL twice, I think you can get the same result even if the
underlying data changed in the meantime.

--
Stas Malyshev
smalyshev@wikimedia.org

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