Django models 如何减少数据库查询的数量（Django、Wagtail、ParentalManytomy）

我有这样一个db结构：

from wagtail.core.models import Page
from modelcluster.fields import ParentalManyToManyField

class BookPage(Page):
    name = models.CharField(#settings)
    author = ParentalManyToManyField(CreatorPage, related_name="author_set")
    illustrator = ParentalManyToManyField(CreatorPage, related_name="illustrator_set")

class CreatorPage(Page):
    name = # etc.
    slug = # etc.

在我的索引页上，我有一张所有书籍的表格，上面印有每个作者/插图画家。我一直在我的模板中使用

{%forbook.author.all%}

，但这意味着对每一行的数据库进行调用，这会变得非常昂贵

似乎与预回迁相关的应该可以工作，但是当我尝试加载页面时，我遇到了一个SQL错误

books = BookPage.objects.live().prefetch_related("author").prefetch_related("illustrator")

错误：

OperationalError at /books/
too many SQL variables
        

SQL查询示例：

SELECT ••• FROM "books_creatorpage" INNER JOIN "books_bookpage_composer" ON ("books_creatorpage"."page_ptr_id" = "books_showpage_composer"."creatorpage_id") INNER JOIN "wagtailcore_page" ON ("books_creatorpage"."page_ptr_id" = "wagtailcore_page"."id") WHERE "books_showpage_composer"."showpage_id" IN ('3294', '95', '99', '102', '105', '108', '116', '118', '126', '129', '131', '139', '145', '149', '152', '156', '894', '900', '1029', '1073', '1088', '1095', '1102', '1131', '1169', '1260', '1267', '1352', '1501', '1625', '1633', '1710', '1727', '1773', '2032', '2131', '2133', '2241', '2315', '2413', '2424', '2745', '2996', '3059', '3115', '3116', '3117', '3118', '3215', '3231', '162', '163', '164', '168', '171', '174', '176', '178', '187', '195', '191', '203', '205', '209', '206', '215', '218', '220', '222', '224', '229', '233', '236', '240', '243', '247', '249', '252', '256', '260', '266', '269', '272', '275', '263', '55', '279', '282', '284', '287', '288', '289', '293', '296', '301', '309', '321', '311', '326', '315', '323', '333', '305', '318', '414', '441', '1466', '1467', '337', '338', '339', '342', '349', '352', '360', '357', '365', '370', '375', '379', '384', '387', '390', '391', '80', '395', '398', '401', '404', '417', '428', '431', '436', '438', '445', '447', '56', '451', '453', '460', '457', '456', '467', '471', '472', '475', '477', '480', '483', '486', '488', '492', '495', '498', '501', '512', '515', '520', '527', '532', '536', '541', '544', '546', '552', '557', '555', '561', '563', '567', '574', '578', '576', '581', '582', '585', '590', '597', '596', '602', '610', '611', '615', '619', '625', '628', '632', '634', '636', '653', '654', '655', '659', '663', '665', '670', '674', '683', '689', '687', '696', '700', '705', '706', '708', '713', '714', '715', '725', '727', '730', '734', '736', '737', '741', '746', '749', '760', '761', '762', '770', '774', '777', '779', '782', '786', '788', '791', '796', '800', '802', '818', '819', '829', '830', '833', '837', '838', 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这肯定是太多的变量了，但我不明白为什么这不起作用

我正在考虑将新字段放入模型中，以保存每个创建者所需的数据，然后重写save（）方法，在对书籍的每次更改中更新此字段，但我希望一定有更好的方法来查询此字段，而不必执行这些额外的步骤