不爲也 比不能也

Disable the features you do not need By default Elasticsearch indexes and adds doc values to most fields so that they can be searched and aggregated out of the box. For instance if you have a numeric field called foo that you need to run histograms on but that you never need to filter on, you can safely disable indexing on this field in your mappings:기본적으로, Elasticsearch는 대부분의 field가 검색되고 aggreg..

Give memory to the filesystem cache Elasticsearch heavily relies on the filesystem cache in order to make search fast. In general, you should make sure that at least half the available memory goes to the filesystem cache so that Elasticsearch can keep hot regions of the index in physical memory.Elasticsearch는 search 속도를 빠르게 하기 위해, filesystem cache에 많이 의존한다. 일반적으로, Elasticsearch가 index 중 많이 사용하는 ..

Use bulk requests Bulk requests will yield much better performance than single-document index requests. In order to know the optimal size of a bulk request, you should run a benchmark on a single node with a single shard. First try to index 100 documents at once, then 200, then 400, etc. doubling the number of documents in a bulk request in every benchmark run. When the indexing speed starts to ..

The fact that Elasticsearch operates with shards and replicas adds challenges when it comes to having good scoring. Elasticsearch가 shard, relpica와 함께 동작한다는 사실은 score 계산에 어려움이 있다는 것을 의미한다. Scores are not reproducible Say the same user runs the same request twice in a row and documents do not come back in the same order both times, this is a pretty bad experience isn’t it? Unfortunately this is so..

When building a search application, stemming is often a must as it is desirable for a query on skiing to match documents that contain ski or skis. But what if a user wants to search for skiing specifically? The typical way to do this would be to use a multi-field in order to have the same content indexed in two different ways:검색 application을 만드는 경우, skiing 에 대한 query가 ski 나 skis 를 포함하는 document와..

Don’t return large result sets Elasticsearch is designed as a search engine, which makes it very good at getting back the top documents that match a query. However, it is not as good for workloads that fall into the database domain, such as retrieving all documents that match a particular query. If you need to do this, make sure to use the Scroll API.Elasticsearch는 search 엔진으로 설계되어, query에 일치하는 ..

Elasticsearch ships with defaults which are intended to give a good out of the box experience. Full text search, highlighting, aggregations, and indexing should all just work without the user having to change anything. Elasticsearch는 바로 적용 가능한 제품을 위해 기본값을 가지고 있다. full text search, highlighting, aggregation, index는 사용자가 아무것도 변경하지 않아도 모두 동작한다. Once you better understand how you want to use Elastic..