from django.contrib.admin.options import IncorrectLookupParameters from django.contrib.admin.views.main import ChangeList from django.core.paginator import InvalidPage, Paginator from django.db import connection class LargeTableChangeList(ChangeList): """ Overrides the count method to get an estimate instead of actual count when not filtered. The only change is the try/catch block calculating 'full_result_count' """ def get_results(self, request): paginator = self.model_admin.get_paginator(request, self.query_set, self.list_per_page) # Get the number of objects, with admin filters applied. result_count = paginator.count # Get the total number of objects, with no admin filters applied. # Perform a slight optimization: Check to see whether any filters were # given. If not, use paginator.hits to calculate the number of objects, # because we've already done paginator.hits and the value is cached. if not self.query_set.query.where: full_result_count = result_count else: try: cursor = connection.cursor() cursor.execute("SELECT reltuples FROM pg_class WHERE relname = %s", [self.root_query_set.query.model._meta.db_table]) full_result_count = int(cursor.fetchone()[0]) except: full_result_count = self.root_query_set.count() can_show_all = result_count <= self.list_max_show_all multi_page = result_count > self.list_per_page # Get the list of objects to display on this page. if (self.show_all and can_show_all) or not multi_page: result_list = self.query_set._clone() else: try: result_list = paginator.page(self.page_num+1).object_list except InvalidPage: raise IncorrectLookupParameters self.result_count = result_count self.full_result_count = full_result_count self.result_list = result_list self.can_show_all = can_show_all self.multi_page = multi_page self.paginator = paginator class LargeTablePaginator(Paginator): """ Overrides the count method to get an estimate instead of actual count when not filtered """ def _get_count(self): """ Changed to use an estimate if the estimate is greater than 10,000 Returns the total number of objects, across all pages. """ if self._count is None: try: estimate = 0 if not self.object_list.query.where: try: cursor = connection.cursor() cursor.execute("SELECT reltuples FROM pg_class WHERE relname = %s", [self.object_list.query.model._meta.db_table]) estimate = int(cursor.fetchone()[0]) except: pass if estimate < 10000: self._count = self.object_list.count() else: self._count = estimate except (AttributeError, TypeError): # AttributeError if object_list has no count() method. # TypeError if object_list.count() requires arguments # (i.e. is of type list). self._count = len(self.object_list) return self._count count = property(_get_count)