findDocuments: improve entity query performance

When I implemented this in 9a4c24c, there were not many rows in
entity_documentproperties in the database here. Now that there are,
computing the document_document -> entity_documentproperties ->
entity_entity join and then filtering is really, really slow. Postgres
seems to materialize the whole join and then scan it.

If we get a set of matching document IDs for the entity query in a
subquery, and then just filter with IN on that, things are much faster:
scan entity_entity; in a nested loop, get the document_ids via
entity_documentproperties; hash this set; and then scan
document_document.

Searching for a single character, this brings the query from ~1.1s to
~400ms. Searching for a full word, ~800ms to 120ms

This condition is getting really ugly -- I am sorry!

References #2935
This commit is contained in:
Will Thompson 2016-06-28 13:11:09 +00:00
parent 92a4e77f9b
commit 8d25e3be78
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@ -35,14 +35,18 @@ def parseCondition(condition, user, item=None):
def buildCondition(k, op, v):
import entity.models
if k == 'id':
v = ox.fromAZ(v)
return Q(**{k: v})
if isinstance(v, bool): #featured and public flag
key = k
elif k == 'entity':
entity_key, v = entity.managers.namePredicate(op, v)
key = 'entities__' + entity_key
entity_key, entity_v = entity.managers.namePredicate(op, v)
key = 'id__in'
v = entity.models.DocumentProperties.objects.filter(**{
'entity__' + entity_key: entity_v
}).values_list('document_id', flat=True)
else:
key = "%s%s" % (k, {
'==': '__iexact',