如何获取出现在Elasticsearch Rails中的文档数量

Question

如果我有很多文档，并且想知道“ rails”一词出现在“多少文档”中，有没有办法从索引中的elasticsearch“ tyre gem”中获取此信息？

Answer 1

You can use Facets to make something like SQL 'group-by' aggregate function, as described here in elasticsearch documentation. A sample code would look like:

index_name = "documents" # name of your index
search_word = 'rails' # word searching for
field_name = 'document_text' # field to search in
search = Tire.search index_name do
  query do
    string "#{field_name}:#{search_word}"
  end
  facet 'ids-facets', :global => false do
    terms :id
  end
end
document_ids = search.results.facets['ids-facets']['terms']

Hope this helps.