如何使Django QuerySet批量删除（）更有效率 [英] How to make Django QuerySet bulk delete() more efficient

问题描述

设置：

Django 1.1.2，MySQL 5.1

Setup:
Django 1.1.2, MySQL 5.1

问题：

Blob.objects.filter(foo = foo) \
            .filter(status = Blob.PLEASE_DELETE) \
            .delete()

此代码段导致ORM首先从xxx_blob生成 SELECT * ... 查询，然后从xxx_blob中执行 DELETE，其中id（BLAH）; 其中BLAH是一个可笑的长列表的id。由于我删除了大量的blob，所以我和DB都很不开心。

This snippet results in the ORM first generating a SELECT * from xxx_blob where ... query, then doing a DELETE from xxx_blob where id in (BLAH); where BLAH is a ridiculously long list of id's. Since I'm deleting a large amount of blobs, this makes both me and the DB very unhappy.

是否有原因？我不明白为什么ORM无法将上述代码段转换为单个DELETE查询。有没有办法优化这个而不诉诸原始的SQL？

Is there a reason for this? I don't see why the ORM can't convert the above snippet into a single DELETE query. Is there a way to optimize this without resorting to raw SQL?

推荐答案

不是没有编写自己的自定义SQL或经理或某事;他们显然正在努力。

Not without writing your own custom SQL or managers or something; they are apparently working on it though.

http： //code.djangoproject.com/ticket/9519

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