Haystack queryset contains None elements

Question

I'm using Haystack for search, and the resulting SearchQuerySet returned contains None elements:

>> SearchQuerySet().models(Question, Document, Idea)
>> [<SearchResult: idea.idea (pk=3875)>, None, None, None]

Running rebuild_index doesn't help. If I remove the .models() call from the first line, the problem goes away. I could just filter out None elements from the results, but I wanted to know if this is intended behaviour?

I am using Django 1.4, Whoosh, and Haystack 2.0.0-beta

Danaedanaher

I haven't tried it yet, but this guy suggests using Solr instead of Whoosh. – Larissa

Update : now I've tried it and it works with Solr. – Larissa

everybody knows that elastic search or solr do and perform better - but for small to mid-sized sites, Whoosh is very ok IMHO and makes no trouble installing/setting up (only afterwards, haha). – Tc

@Danaedanaher are you using solr as well, now? – Tc

@Danaedanaher having an answer two years later, you could accept it after two more years, no? ;-) at least it is the only answer that does somehow resolve the problem, and does not suggest installing a different backend ;-) – Tc

Answer 1

I had this problem when haystack index had records without corresponding records in DB.

Turboelectric

Thanks, this isn't the problem though. It turns out the 'None' values correspond to User objects. Apparently the models function removes hits that aren't of the right model type but leaves a None type instead of filtering them out – Danaedanaher

Can't you say, is this problem only for 'whoosh' backend? Does using Solr engine solves it? – Freddiefreddy

So there's no solution for Whoosh then? – Ous

Answer 2

No, it is definitly not the intended behaviour, and as I can see, seems to be related to a design decision in Whoosh. And, as of December 2015, this still seems to be an issue, as can be seen here. Also, I can reproduce it with my setup (django 1.8.5, haystack 2.4.1, Whoosh 2.7.0) - that's why I came here.

Quick and dirty solution that worked for me: Define a new field on your index (type/model/tomato), set it the same for each model, and filter against that value:

.filter(type='my_modelname')

instead of

.models(MyModel).

I don't know (yet) how this scales, but seems to work ok.

Tc

Answer 3

Had the same problem using Whoosh, installed Elasticsearch and the None elements went away.

Oates