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从1.7移动到5.4时,Elasticsearch查询结果不同

elasticsearch-2.0 elasticsearch-5 elasticsearch

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mnd · 技术社区 · 9 年前

我正在将Elasticsearch实例从1.7升级到5.4.3,并注意到两个系统之间的搜索结果不同,即使使用相同的查询。

{
  "query": {
    "filtered": {
      "query": {
        "multi_match": {
          "query": "something",
          "fields": [
            "field1",
            "field2",
            "field3"
          ],
          "operator": "and"
        }
      }
    }
  }
}

Elasticsearch 5.4查询

{
  "query": {
    "bool": {
      "must": [
        {
          "multi_match": {
            "query": "something",
            "fields": [
              "field1",
              "field2",
              "field3"
            ],
            "operator": "and"
          }
        }
      ]
    }
  }
}

_explain 最终,我发现评分方式有所不同。此外,此查询包括搜索查询匹配的同义词。

{
    "_index": "...",
    "_type": "...",
    "_id": "...",
    "matched": true,
    "explanation": {
        "value": 9.963562,
        "description": "max of:",
        "details": [
            {
                "value": 3.1413355,
                "description": "sum of:",
                "details": [
                    {
                        "value": 1.0609967,
                        "description": "weight(field1:something in 13) [PerFieldSimilarity], result of:",
                        "details": [
...remainder removed for brevity

解释Elasticsearch 5.4

{
    "_index": "...",
    "_type": "...",
    "_id": "...",
    "matched": true,
    "explanation": {
        "value": 7.1987557,
        "description": "sum of:",
        "details": [
            {
                "value": 7.1987557,
                "description": "max of:",
                "details": [
                    {
                        "value": 6.659632,
                        "description": "weight(Synonym(field1:something field1:something2 field1:something3) in 113) [PerFieldSimilarity], result of:",
                        "details": [
...remainder removed for brevity

问题

事实上 Elasticsearch 1.7显示的查询 max of sum of 对于计算,它是 对面的 对于Elasticsearch 5.4,指出部分问题?

1 回复 | 直到 9 年前

1

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mnd 9 年前

默认的“相似性”在Elasticsearch 5.0中从TF/IDF更改为BM25

从技术上讲,这实际上是一个变化,当移动到Lucene 6.2(默认的Elasticsearch 5.0.0)。

Elasticsearch 5.0.0 Release Notes 包括以下行:

#18948 (问题: #18944 )

你可以阅读更多关于 Elasticsearch similarity here

similarity 在要使用的映射文件中 classic

description:
  type: text
  similarity: classic

包含更多信息的有用链接: