[DOCS] Rewrite dis max query (#43586)

docs/reference/query-dsl/dis-max-query.asciidoc

@@ -1,48 +1,63 @@
 [[query-dsl-dis-max-query]]
-=== Dis Max Query
+=== Disjunction Max Query
 
-A query that generates the union of documents produced by its
-subqueries, and that scores each document with the maximum score for
-that document as produced by any subquery, plus a tie breaking increment
-for any additional matching subqueries.
+Returns documents matching one or more wrapped queries, called query clauses or
+clauses.
 
-This is useful when searching for a word in multiple fields with
-different boost factors (so that the fields cannot be combined
-equivalently into a single search field). We want the primary score to
-be the one associated with the highest boost, not the sum of the field
-scores (as Boolean Query would give). If the query is "albino elephant"
-this ensures that "albino" matching one field and "elephant" matching
-another gets a higher score than "albino" matching both fields. To get
-this result, use both Boolean Query and DisjunctionMax Query: for each
-term a DisjunctionMaxQuery searches for it in each field, while the set
-of these DisjunctionMaxQuery's is combined into a BooleanQuery.
+If a returned document matches multiple query clauses, the `dis_max` query
+assigns the document the highest relevance score from any matching clause, plus
+a tie breaking increment for any additional matching subqueries.
 
-The tie breaker capability allows results that include the same term in
-multiple fields to be judged better than results that include this term
-in only the best of those multiple fields, without confusing this with
-the better case of two different terms in the multiple fields. The
-default `tie_breaker` is `0.0`.
+You can use the `dis_max` to search for a term in fields mapped with different
+<<mapping-boost,boost>> factors.
 
-This query maps to Lucene `DisjunctionMaxQuery`.
+[[query-dsl-dis-max-query-ex-request]]
+==== Example request
 
 [source,js]
---------------------------------------------------
+----
 GET /_search
 {
     "query": {
         "dis_max" : {
-            "tie_breaker" : 0.7,
-            "boost" : 1.2,
             "queries" : [
-                {
-                    "term" : { "age" : 34 }
-                },
-                {
-                    "term" : { "age" : 35 }
-                }
-            ]
+                { "term" : { "title" : "Quick pets" }},
+                { "term" : { "body" : "Quick pets" }}
+            ],
+            "tie_breaker" : 0.7
         }
     }
 }    
---------------------------------------------------
+----
 // CONSOLE
+
+[[query-dsl-dis-max-query-top-level-params]]
+==== Top-level parameters for `dis_max`
+
+`queries` (Required)::
+(array of query objects) Contains one or more query clauses. Returned documents
+**must match one or more** of these queries. If a document matches multiple
+queries, {es} uses the highest <<query-filter-context, relevance score>>.
+
+`tie_breaker` (Optional)::
++
+--
+(float) Floating point number between `0` and `1.0` used to increase the
+<<query-filter-context, relevance scores>> of documents matching multiple query
+clauses. Defaults to `0.0`.
+
+You can use the `tie_breaker` value to assign higher relevance scores to
+documents that contain the same term in multiple fields than documents that
+contain this term in only the best of those multiple fields, without confusing
+this with the better case of two different terms in the multiple fields.
+
+If a document matches multiple clauses, the `dis_max` query calculates the
+relevance score for the document as follows:
+
+. Take the relevance score from a matching clause with the highest score.
+. Multiply the score from any other matching clauses by the `tie_breaker` value.
+. Add the highest score to the multiplied scores.
+
+If the `tie_breaker` value is greater than `0.0`, all matching clauses count,
+but the clause with the highest score counts most.
+--