Move back to BM25 similarity

docs/reference/aggregations/metrics/tophits-aggregation.asciidoc

@@ -332,7 +332,7 @@ Top hits response snippet with a nested hit, which resides in the first slot of
                    "value": 1,
                    "relation": "eq"
                 },
-                "max_score": 0.3616575,
+                "max_score": 0.16438977,
                 "hits": [
                   {
                     "_index": "sales",
@@ -342,7 +342,7 @@ Top hits response snippet with a nested hit, which resides in the first slot of
                       "field": "comments",  <1>
                       "offset": 0 <2>
                     },
-                    "_score": 0.3616575,
+                    "_score": 0.16438977,
                     "_source": {
                       "comment": "This car could have better brakes", <3>
                       "username": "baddriver007"

docs/reference/analysis/charfilters/pattern-replace-charfilter.asciidoc

@@ -245,13 +245,13 @@ The output from the above is:
         "value": 1,
         "relation": "eq"
     },
-    "max_score": 0.2876821,
+    "max_score": 0.13076457,
     "hits": [
       {
         "_index": "my_index",
         "_type": "_doc",
         "_id": "1",
-        "_score": 0.2876821,
+        "_score": 0.13076457,
         "_source": {
           "text": "The fooBarBaz method"
         },

docs/reference/analysis/tokenizers/edgengram-tokenizer.asciidoc

@@ -304,13 +304,13 @@ GET my_index/_search
         "value": 1,
         "relation": "eq"
     },
-    "max_score": 0.5753642,
+    "max_score": 0.26152915,
     "hits": [
       {
         "_index": "my_index",
         "_type": "_doc",
         "_id": "1",
-        "_score": 0.5753642,
+        "_score": 0.26152915,
         "_source": {
           "title": "Quick Foxes"
         }

docs/reference/how-to/recipes/stemming.asciidoc

@@ -88,13 +88,13 @@ GET index/_search
         "value": 2,
         "relation": "eq"
     },
-    "max_score": 0.18232156,
+    "max_score": 0.082873434,
     "hits": [
       {
         "_index": "index",
         "_type": "_doc",
         "_id": "1",
-        "_score": 0.18232156,
+        "_score": 0.082873434,
         "_source": {
           "body": "Ski resort"
         }
@@ -103,7 +103,7 @@ GET index/_search
         "_index": "index",
         "_type": "_doc",
         "_id": "2",
-        "_score": 0.18232156,
+        "_score": 0.082873434,
         "_source": {
           "body": "A pair of skis"
         }
@@ -149,13 +149,13 @@ GET index/_search
         "value": 1,
         "relation": "eq"
     },
-    "max_score": 0.8025915,
+    "max_score": 0.3648143,
     "hits": [
       {
         "_index": "index",
         "_type": "_doc",
         "_id": "1",
-        "_score": 0.8025915,
+        "_score": 0.3648143,
         "_source": {
           "body": "Ski resort"
         }
@@ -209,13 +209,13 @@ GET index/_search
         "value": 1,
         "relation": "eq"
     },
-    "max_score": 0.8025915,
+    "max_score": 0.3648143,
     "hits": [
       {
         "_index": "index",
         "_type": "_doc",
         "_id": "1",
-        "_score": 0.8025915,
+        "_score": 0.3648143,
         "_source": {
           "body": "Ski resort"
         }

docs/reference/mapping/params/normalizer.asciidoc

@@ -93,13 +93,13 @@ both index and query time.
         "value": 2,
         "relation": "eq"
     },
-    "max_score": 0.47000363,
+    "max_score": 0.21363801,
     "hits": [
       {
         "_index": "index",
         "_type": "_doc",
         "_id": "1",
-        "_score": 0.47000363,
+        "_score": 0.21363801,
         "_source": {
           "foo": "BÀR"
         }
@@ -108,7 +108,7 @@ both index and query time.
         "_index": "index",
         "_type": "_doc",
         "_id": "2",
-        "_score": 0.47000363,
+        "_score": 0.21363801,
         "_source": {
           "foo": "bar"
         }

docs/reference/query-dsl/terms-set-query.asciidoc

@@ -76,13 +76,13 @@ Response:
         "value": 1,
         "relation": "eq"
     },
-    "max_score": 0.87546873,
+    "max_score": 0.39794034,
     "hits": [
       {
         "_index": "my-index",
         "_type": "_doc",
         "_id": "2",
-        "_score": 0.87546873,
+        "_score": 0.39794034,
         "_source": {
           "codes": ["def", "ghi"],
           "required_matches": 2

docs/reference/search/explain.asciidoc

@@ -34,18 +34,13 @@ This will yield the following result:
    "_id":"0",
    "matched":true,
    "explanation":{
-      "value":1.6943597,
+      "value":0.7701635,
       "description":"weight(message:elasticsearch in 0) [PerFieldSimilarity], result of:",
       "details":[
          {
-            "value":1.6943597,
+            "value":0.7701635,
             "description":"score(freq=1.0), product of:",
             "details":[
-               {
-                  "value":2.2,
-                  "description":"boost",
-                  "details":[]
-               },
                {
                   "value":1.3862944,
                   "description":"idf, computed as log(1 + (N - n + 0.5) / (n + 0.5)) from:",

docs/reference/search/request-body.asciidoc

@@ -35,13 +35,13 @@ And here is a sample response:
             "value": 1,
             "relation": "eq"
         },
-        "max_score": 1.3862944,
+        "max_score": 0.6301338,
         "hits" : [
             {
                 "_index" : "twitter",
                 "_type" : "_doc",
                 "_id" : "0",
-                "_score": 1.3862944,
+                "_score": 0.6301338,
                 "_source" : {
                     "user" : "kimchy",
                     "message": "trying out Elasticsearch",

docs/reference/search/request/highlighting.asciidoc

@@ -864,13 +864,13 @@ Response:
             "value": 1,
             "relation": "eq"
         },
-        "max_score": 1.601195,
+        "max_score": 0.72781587,
         "hits": [
             {
                 "_index": "twitter",
                 "_type": "_doc",
                 "_id": "1",
-                "_score": 1.601195,
+                "_score": 0.72781587,
                 "_source": {
                     "user": "test",
                     "message": "some message with the number 1",
@@ -923,13 +923,13 @@ Response:
             "value": 1,
             "relation": "eq"
         },
-        "max_score": 1.601195,
+        "max_score": 0.72781587,
         "hits": [
             {
                 "_index": "twitter",
                 "_type": "_doc",
                 "_id": "1",
-                "_score": 1.601195,
+                "_score": 0.72781587,
                 "_source": {
                     "user": "test",
                     "message": "some message with the number 1",

docs/reference/search/request/inner-hits.asciidoc

@@ -274,13 +274,13 @@ Response not included in text but tested for completeness sake.
         "value": 1,
         "relation": "eq"
     },
-    "max_score": 1.0444684,
+    "max_score": 0.47475836,
     "hits": [
       {
         "_index": "test",
         "_type": "_doc",
         "_id": "1",
-        "_score": 1.0444684,
+        "_score": 0.47475836,
         "_source": ...,
         "inner_hits": {
           "comments": { <1>
@@ -289,7 +289,7 @@ Response not included in text but tested for completeness sake.
                 "value": 1,
                 "relation": "eq"
               },
-              "max_score": 1.0444684,
+              "max_score": 0.47475836,
               "hits": [
                 {
                   "_index": "test",
@@ -299,7 +299,7 @@ Response not included in text but tested for completeness sake.
                     "field": "comments",
                     "offset": 1
                   },
-                  "_score": 1.0444684,
+                  "_score": 0.47475836,
                   "fields": {
                     "comments.text.keyword": [
                       "words words words"
@@ -395,13 +395,13 @@ Which would look like:
         "value": 1,
         "relation": "eq"
     },
-    "max_score": 0.6931472,
+    "max_score": 0.3150669,
     "hits": [
       {
         "_index": "test",
         "_type": "_doc",
         "_id": "1",
-        "_score": 0.6931472,
+        "_score": 0.3150669,
         "_source": ...,
         "inner_hits": {
           "comments.votes": { <1>
@@ -410,7 +410,7 @@ Which would look like:
                   "value": 1,
                   "relation": "eq"
               },
-              "max_score": 0.6931472,
+              "max_score": 0.3150669,
               "hits": [
                 {
                   "_index": "test",
@@ -424,7 +424,7 @@ Which would look like:
                       "offset": 0
                     }
                   },
-                  "_score": 0.6931472,
+                  "_score": 0.3150669,
                   "_source": {
                     "value": 1,
                     "voter": "kimchy"

docs/reference/search/uri-request.asciidoc

@@ -31,13 +31,13 @@ And here is a sample response:
             "value": 1,
             "relation": "eq"
         },
-        "max_score": 1.3862944,
+        "max_score": 0.6301338,
         "hits" : [
             {
                 "_index" : "twitter",
                 "_type" : "_doc",
                 "_id" : "0",
-                "_score": 1.3862944,
+                "_score": 0.6301338,
                 "_source" : {
                     "user" : "kimchy",
                     "date" : "2009-11-15T14:12:12",

qa/rolling-upgrade/src/test/java/org/elasticsearch/upgrades/IndexingIT.java

@@ -19,13 +19,13 @@
 package org.elasticsearch.upgrades;
 
 import org.apache.http.util.EntityUtils;
+import org.elasticsearch.Version;
+import org.elasticsearch.client.Request;
+import org.elasticsearch.client.Response;
 import org.elasticsearch.common.Booleans;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.rest.action.document.RestBulkAction;
-import org.elasticsearch.Version;
-import org.elasticsearch.client.Request;
-import org.elasticsearch.client.Response;
 
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
@@ -145,7 +145,7 @@ public void testIndexing() throws IOException {
         }
     }
 
-    private void bulk(String index, String valueSuffix, int count) throws IOException {
+    private static void bulk(String index, String valueSuffix, int count) throws IOException {
         StringBuilder b = new StringBuilder();
         for (int i = 0; i < count; i++) {
             b.append("{\"index\": {\"_index\": \"").append(index).append("\", \"_type\": \"_doc\"}}\n");