java - Mongodb cursor inconsistent behavior -


i have collection on billion documents. when iterate on them cursor , processing, don't docs. however, if iterate on collection , count, return right count.

double c = 0; while(cursor.hasnext){       dbobject entity = entities.next();       //do       c+=1     }  assert(c==446642690.0)

the assertion fails unless don't , count.

are doing updates or deletes during processing? if case running issue mongo cursor not isolated updates/inserts during lifetime. can partially avoid behaviour snapshot mode it's limited. see mongo documentation under cursor isolation more information issue. mongo designed work way think need find way deal situation.


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