查询上下文是否在 elasticsearch 中的过滤上下文之前评估？ 如何确定评价顺序？

Question

I am using the below query:

GET customer/doc/_search?routing=123
{
  "query": {
    "bool": {
      "filter": [
        {
          "term": {
            "location": "Delhi"
          }
        }
      ],
      "should": [
        {
          "match_phrase_prefix": {
            "phone": {
              "query": "650",
              "max_expansions": 100
            }
          }
        }
      ]
    }
  }
}

The problem is my search on phone isn't working anymore. It used to work fine when I had less data, now every shard has data for multiple locations. Search on phone now requires me to type in 6 or 7 characters at times. (There may be matching phone numbers that have different location but are on this shard)

This is due to max_expansions I am guessing. When I increase it to 500 it does return me search results (not all), but the query becomes slow.

Isn't there a way to force es to apply filter first (and restrict the dataset) and then apply the should clause, so that I get the matching results even with small value of max_expansions?

Any help is appreciated.

Answer 1

It is due to max_expansions. Restricting dataset is not exactly what you may want to do ( Thats also not very straight forward - you may have to use some script which will in turn slowdown query).

When you query for a wildcard expression, Lucene expands the wildcard expression into set of actual terms in your inverted index term dictionary. Now, when you restrict the term expansion to 500 - it might miss a few.

I would consider using prefixes during indexing phase. Prefixes helps to avoid the costly expansion in runtime phase.