Elasticsearch返回重复的项目？

Question

我在应用程序的某些部分使用了elasticsearch，由于某种原因，我的某些用户会收到重复的条目。

这是搜索：

def newest_messages_for_user_by_elasticsearch(user)
  filter_conditions = {
      must: {term: {state: 'accepted'}},
      must_not: [
        {term: {"user_id" => user.id}}
      ]
    }

  self.search(
    query: { match_all: {} },
    filter: {bool: filter_conditions},
    sort: [
      {created_at: {order: :desc}}
    ]
  )
end

有谁可以告诉我为什么它会返回重复的项目？

这两个请求看起来像这样：

GET http://localhost:9200/development_messages/message/_search?from=0&size=20 [status:200, request:0.002s, query:0.001s]
GET http://localhost:9200/development_messages/message/_search?from=20&size=20 [status:200, request:0.008s, query:0.002s]

谢谢！