eggjs使用sequelize的事务无法插入数据

代码如下：

async create( userId, title, content, subjectId, type, categoryId, coverImageUrl, tags, published ) { const ctx = this.ctx; let transaction;

try {
  transaction = await ctx.model.transaction();

  const post = await ctx.model.Post.create(
    {
      author_id: userId,
      title,
      content,
      type,
      category_id: categoryId,
      cover_image_url: coverImageUrl,
      subject_id: subjectId,
      published,
      created_at: new Date(),
      updated_at: null,
      deleted_at: null,
      length: 2,
      render_content: "",
      subtitle: "",
      leading_text: ""
    },
    { transaction }
  );

  const postId = post && post.getDataValue("id");

  if (!postId) {
    throw new Error();
  }

  const tagIds = [];

  for (const tagName of tags) {
    const result = await ctx.model.Tag.findOrCreate({
      where: { name: tagName },
      transaction
    });

    tagIds.push(result[0].dataValues["id"]);
  }

  for (const tagId of tagIds) {
    await ctx.model.PostTag.create(
      { post_id: postId, tag_id: tagId },
      { transaction }
    );
  }

  await transaction.commit();

  return { success: true, data: { postId } };
} catch (e) {
  console.log(e);
  await transaction.rollback();
  return { success: false, message: "服务器异常" };
}

}

没有提示错误，可以返回postId，但查数据库后，数据根本没插进去，请问是什么原因呢？