diff --git a/docs/reference/glossary.asciidoc b/docs/reference/glossary.asciidoc index 0012beebdca..53164d366cd 100644 --- a/docs/reference/glossary.asciidoc +++ b/docs/reference/glossary.asciidoc @@ -61,6 +61,15 @@ `object`. The mapping also allows you to define (amongst other things) how the value for a field should be analyzed. +[[glossary-filter]] filter :: + + A filter is a non-scoring <>, meaning that it does not score documents. + It is only concerned about answering the question - "Does this document match?". + The answer is always a simple, binary yes or no. This kind of query is said to be made + in a <>, + hence it is called a filter. Filters are simple checks for set inclusion or exclusion. + In most cases, the goal of filtering is to reduce the number of documents that have to be examined. + [[glossary-index]] index :: An index is like a _table_ in a relational database. It has a @@ -105,6 +114,16 @@ + See also <> +[[glossary-query]] query :: + + A query is the basic component of a search. A search can be defined by one or more queries + which can be mixed and matched in endless combinations. While <> are + queries that only determine if a document matches, those queries that also calculate how well + the document matches are known as "scoring queries". Those queries assign it a score, which is + later used to sort matched documents. Scoring queries take more resources than <> + and their query results are not cacheable. As a general rule, use query clauses for full-text + search or for any condition that requires scoring, and use filters for everything else. + [[glossary-replica-shard]] replica shard :: Each <> can have zero or more @@ -161,8 +180,9 @@ A term is an exact value that is indexed in Elasticsearch. The terms `foo`, `Foo`, `FOO` are NOT equivalent. Terms (i.e. exact values) can - be searched for using _term_ queries. + - See also <> and <>. + be searched for using _term_ queries. + + + See also <> and <>. [[glossary-text]] text ::