Django elasticsearch-dsl 在 pre_save 上更新 M2M

我正在使用 django-elasticsearch-dsl 包，但有点进退两难。这是我的代码：

模型.py

class Source(models.model):
    name = models.CharField(max_length=50)

class Posting(models.Model):
    title = models.CharField(max_length=250)
    sources = models.ManyToMany(Sources, related_name="postings", through="PostingSource")

class PostingSource(models.Model):
    posting = models.ForeignKey(Posting, related_name="posting_sources", on_delete=models.CASCADE)
    source = models.ForeignKey(Source, related_name="posting_sources", on_delete=models.CASCADE)

文件.py

class PostingDocument(Document):
    sources = fields.ObjectField(properties={"name": fields.KeywordField()})

    class Index:
        name = "posting"
        settings = {"all the settings stuff"}

    class Django:
        model = Posting
        fields = ["title"]
        related_models = [PostingSource]

    def get_queryset(self):
        return super().get_queryset().select_related("sources")

    def get_instance_from_related(self, related_instance):
        if isinstance(related_instance, PostingSource):
            return related_instance.posting

我的问题是，当我更新帖子的来源时，出于某种原因，elasticsearch 索引会更新为 pre_save 而不是 post_save。我基本上必须使用相同的源执行 2 次放置请求，以便更改反映在我的索引中。我def prepare_sources(self, instance):在文档中添加了一个，它似乎可以工作，但感觉以后会导致性能问题。任何帮助或指导将不胜感激。