Performance issues when retrieving datasets per instrument

Both

https://icatplus.esrf.fr/catalogue/sessionId/dataset?sortBy=STARTDATE&sortOrder=-1&datasetType=acquisition&nested=false&instrumentName=ID23-1&limit=20&skip=0

and

https://icatplus.esrf.fr/catalogue/sessionId/dataset?sortBy=STARTDATE&sortOrder=-1&datasetType=acquisition&nested=true&instrumentName=ID23-1&limit=20&skip=0

are very slow (8 to 30 seconds for both of them when I test it).

So I think the slowness comes from the instrumentName=ID23-1 filter, it is not that slow when using investigationId filter.