不爲也 比不能也

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..

The term query is useful for finding a single value, but often you’ll want to search for multiple values.What if you want to find documents that have a price of $20 or $30?term query는 단일 값을 찾는데 유용하다. 그러나, 가끔은 다중 값을 찾을 수도 있다. 가격이 $20 또는 $30인 document를 찾으려면 어떻게 해야 할까?Rather than using multiple term queries, you can instead use a single terms query (note the s at the end). The terms query is simply..

Earlier in this chapter (Internal Filter Operation), we briefly discussed how non-scoring queries are calculated. At their heart is a bitset representing which documents match the filter. When Elasticsearch determines a bitset is likely to be reused in the future, it will be cached directly in memory for later use. Once cached, these bitsets can be reused wherever the same query is used, without..