不爲也 比不能也

If you have no idea what questions you will want to ask your data when you start ingesting it, columnar storage is probably a good option for you: it helps in two areas that are often close to the heart of users who deal with large amounts of data:data를 index하기 시작할 때, 어떤 query를 해야하는지 잘 모를 경우, 아마도 column 저장소가 좋은 선택일 수 있다. 이는 방대한 양의 data를 처리하는 사용자의 의도와 가까운 2가지 영역에 도움이 된다. Storage efficiency: Since..

string fields replaced by text/keyword fieldseditThe string field datatype has been replaced by the text field for full text analyzed content, and the keyword field for not-analyzed exact string values. For backwards compatibility purposes, during the 5.x series:string field datatype이 full text analyzed 내용에 대해서는 text field로, not-analyzed exact string 값에 대해서는 keyword field로 변경되었다. 이전 version과의 호환..

A number of changes have been made to mappings to remove ambiguity and to ensure that conflicting mappings cannot be created.모호함을 제거하고, mapping의 충돌이 일어나지 않도록 하기 위해, mapping에 많은 변경이 있었다.One major change is that dynamically added fields must have their mapping confirmed by the master node before indexing continues. This is to avoid a problem where different shards in the same index dynamically add..

Some aggregations, such as the terms bucket, operate on string fields. And string fields may be either analyzed or not_analyzed, which raises the question: how does analysis affect aggregations?terms bucket 같은 어떤 aggregation은 string field에서 동작한다. 그리고, string field는 analyzed 나 not_analyzed 일 것이다. 그렇다면 질문이 있을 것이다. 분석은 aggregation에 어떤 영향을 미치는가?The answer is "a lot," for two reasons: analysis affect..

Once analyzed strings have been loaded into fielddata, they will sit there until evicted (or your node crashes). For that reason it is important to keep an eye on this memory usage, understand how and when it loads, and how you can limit the impact on your cluster.일단 analyzed string이 fielddata에 로드되면, 그것들은 추출될 (또는 node가 crash)) 때까지 그 곳에 있을 것이다. 이런 이유로 이런 메모리 사용을 관찰하고, 그것이 언제 어떻게 로드되는지를 이해하고, clus..

Imagine that you are running a website that allows users to listen to their favorite songs. To make it easier for them to manage their music library, users can tag songs with whatever tags make sense to them. You will end up with a lot of tracks tagged with rock, hiphop, and electronica, but also with some tracks tagged with my_16th_birthday_favorite_anthem.사용자들이 각자가 좋아하는 노래를 들을 수 있는 website를 운영..

The default behavior of Elasticsearch is to load in-memory fielddata lazily. The first time Elasticsearch encounters a query that needs fielddata for a particular field, it will load that entire field into memory for each segment in the index.Elasticsearch의 기본 동작은 in-memory fielddata를 지연시켜(lazily) 로드 하는 것이다. Elasticsearch가 특정 field에 대해, fielddata가 필요한, query를 처음으로 만나면, index에 있는 각 segment에 대해, 전..

This section covered a lot of ground, and a lot of deeply technical issues. Aggregations bring a power and flexibility to Elasticsearch that is hard to overstate. The ability to nest buckets and metrics, to quickly approximate cardinality and percentiles, to find statistical anomalies in your data, all while operating on near-real-time data and in parallel to full-text search—these are game-chan..