不爲也 比不能也

While playing around with the data in our index, we notice something odd. Something seems to be broken: we have 12 tweets in our indices, and only one of them contains the date 2014-09-15, but have a look at the total hits for the following queries:index에 있는 데이터를 살펴보다 보면, 이상한 점을 발견할 수 있다. 뭔가 깨진 것 같다. index에는 12개의 tweet이 있다. 그 중의 단 하나만 2014-09-15 를 포함하고 있다. 그런데 아래 query의 total hits를 보면GET /_searc..

Data in Elasticsearch can be broadly divided into two types: exact values and full text.Elasticsearch에서 데이터는 크게 두 가지(exact value와 full text) 형태로 나누어진다.Exact values are exactly what they sound like. Examples are a date or a user ID, but can also include exact strings such as a username or an email address. The exact value Foo is not the same as the exact value foo. The exact value 2014 is not the..

While Elasticsearch comes with many queries, you will use just a few frequently. We discuss them in much greater detail in Search in Depth but next we give you a quick introduction to the most important queries.Elasticsearch에는 많은 query가 있지만, 자주 사용하는 것은 소수일 것이다. Search in Depth에서, 훨씬 더 자세히 이야기할 것이다. 아래에서 가장 중요한 query들에 대해 빠르게 소개하겠다.match_all QueryeditThe match_all query simply matches all documen..

When working with exact values, you will be working with non-scoring, filtering queries. Filters are important because they are very fast. They do not calculate relevance (avoiding the entire scoring phase) and are easily cached. We’ll talk about the performance benefits of filters later in All About Caching, but for now, just keep in mind that you should use filtering queries as often as you ca..

Queries can find only terms that actually exist in the inverted index, so it is important to ensure that the same analysis process is applied both to the document at index time, and to the query string at search time so that the terms in the query match the terms in the inverted index.query는 inverted index에 실제로 존재하는 단어만을 찾을 수 있다. 따라서 document를 index할할 때 적용되는 프로세스와, 검색 시 query string에 적용되는 프로세스가,..

The final topic that we should touch on before leaving multifield queries is that of exact-value not_analyzed fields. It is not useful to mix not_analyzed fields with analyzed fields in multi_matchqueries.다중 field 검색을 마치기 전에, 다뤄야 할 마지막 주제는, exact-value not_analyzed field이다. multi_match query에서, not_analyzed field와 analyzed field를 섞는 것은 유용하지 않다.The reason for this can be demonstrated easily by lo..