Elasticsearch scripted_metric null_pointer_exception

Question

我正在尝试使用 scripted_metric Elasticsearch 的 aggs 和通常情况下，它与我的其他脚本完美配合

但是，使用下面的脚本，我遇到了一个名为“null_pointer_exception”的错误，但它们只是复制粘贴的脚本并且已经为 6 个模块工作

$max = 10;

{
    "query": {
        "match_all": {}
        //omitted some queries here, so I just turned it into match_all
    }
  },
  "aggs": {
    "ARTICLE_CNT_PDAY": {
      "histogram": {
        "field": "pub_date",
        "interval": "86400"
      },
      "aggs": {
        "LATEST": {
          "nested": {
            "path": "latest"
          },
          "aggs": {
            "SUM_SVALUE": {
              "scripted_metric": {
                "init_script": "
                    state.te = [];
                    state.g = 0;
                    state.d = 0;
                    state.a = 0;
                ",
                "map_script": "
                    if(state.d != doc['_id'].value){
                        state.d = doc['_id'].value;
                        state.te.add(state.a);
                        state.g = 0;
                        state.a = 0;
                    }
                    state.a = doc['latest.soc_mm_score'].value;
                ",
                "combine_script": "
                    state.te.add(state.a);
                    double count = 0;
                    for (t in state.te) {
                        count += ((t*10)/$max)
                    }
                    return count;
                ",
                "reduce_script": "
                    double count = 0;
                    for (a in states) {
                        count += a;
                    }
                    return count;
                "
              }
            }
          }
        }
      }
    }
  }
}

我尝试在 Kibana 中运行此脚本，这是错误消息:



我得到的是， reduce_script 有问题部分，试图改变这部分:

来自

for (a in states) {
    count += a;
}

至

for (a in states) {
    count += 1;
}

并且工作得很好，我觉得 a变量没有得到它应该持有的东西

这里有什么想法吗？非常感谢您的帮助，非常感谢!

Answer 1

原因解释here :

If a parent bucket of the scripted metric aggregation does not collect any documents an empty aggregation response will be returned from the shard with a null value. In this case the reduce_script's states variable will contain null as a response from that shard. reduce_script's should therefore expect and deal with null responses from shards.

所以很明显你的一个桶是空的，你需要像这样处理那个空:

            "reduce_script": "
                double count = 0;                    
                for (a in states) {
                    count += (a ?: 0);
                }
                return count;
            "