Remove (dfs_)query_and_fetch from the REST API

Remove the ability to specify search type ‘query_and_fetch’ and
‘df_query_and_fetch’ from the REST API.

- Adds REST tests
- Updates REST API spec to remove ‘query_and_fetch’ and
‘df_query_and_fetch’ as options
- Removes documentation for these options

Closes #9606

docs/reference/search/request/search-type.asciidoc

@@ -82,23 +82,4 @@ Parameter value: *scan*.
 The `scan` search type disables sorting in order to allow very efficient
 scrolling through large result sets.  See <<scroll-scan>> for more.
 
-[[query-and-fetch]]
-==== Query And Fetch
-
-Parameter value: *query_and_fetch*.
-
-The `query_and_fetch` mode is an *internal* optimization which
-is chosen automatically when a `query_then_fetch` request
-targets a single shard only.  Both phases of `query_then_fetch`
-are executed in a single pass.  This mode should not be
-explicitly specified by the user.
-
-[[dfs-query-and-fetch]]
-==== Dfs, Query And Fetch
-
-Parameter value: *dfs_query_and_fetch*.
-
-Same as `query_and_fetch`, except for an initial scatter phase which
-goes and computes the distributed term frequencies for more accurate
-scoring. This mode should not be explicitly specified by the user.
 

rest-api-spec/api/search.json

@@ -90,7 +90,7 @@
         },
         "search_type": {
           "type" : "enum",
-          "options" : ["query_then_fetch", "query_and_fetch", "dfs_query_then_fetch", "dfs_query_and_fetch", "count", "scan"],
+          "options" : ["query_then_fetch", "dfs_query_then_fetch", "count", "scan"],
           "description" : "Search operation type"
         },
         "size": {

rest-api-spec/test/search/issue9606.yaml

@@ -0,0 +1,44 @@
+---
+setup:
+  - do:
+      indices.create:
+          index: test
+
+  - do:
+      index:
+          index:  test
+          type:   test
+          id:     1
+          body:   { foo: bar }
+
+  - do:
+      indices.refresh:
+        index: [test]
+
+---
+"Test search_type=query_and_fetch not supported from REST layer":
+
+  - do:
+      catch: request
+      search:
+          index: test
+          type:  test
+          search_type: query_and_fetch
+          body:
+              query:
+                match:
+                  foo: bar
+
+---
+"Test search_type=dfs_query_and_fetch not supported from REST layer":
+
+  - do:
+      catch: request
+      search:
+          index: test
+          type:  test
+          search_type: dfs_query_and_fetch
+          body:
+              query:
+                match:
+                  foo: bar

src/main/java/org/elasticsearch/rest/action/search/RestSearchAction.java

@@ -22,6 +22,7 @@ package org.elasticsearch.rest.action.search;
 import org.elasticsearch.ElasticsearchIllegalArgumentException;
 import org.elasticsearch.action.search.SearchRequest;
 import org.elasticsearch.action.search.SearchResponse;
+import org.elasticsearch.action.search.SearchType;
 import org.elasticsearch.action.support.IndicesOptions;
 import org.elasticsearch.client.Client;
 import org.elasticsearch.common.Strings;
@@ -96,8 +97,18 @@ public class RestSearchAction extends BaseRestHandler {
             }
         }
 
+        // do not allow 'query_and_fetch' or 'dfs_query_and_fetch' search types
+        // from the REST layer. these modes are an internal optimization and should
+        // not be specified explicitly by the user.
+        String searchType = request.param("search_type");
+        if (SearchType.fromString(searchType).equals(SearchType.QUERY_AND_FETCH) ||
+                SearchType.fromString(searchType).equals(SearchType.DFS_QUERY_AND_FETCH)) {
+            throw new ElasticsearchIllegalArgumentException("Unsupported search type [" + searchType + "]");
+        } else {
+            searchRequest.searchType(searchType);
+        }
+
         searchRequest.extraSource(parseSearchSource(request));
-        searchRequest.searchType(request.param("search_type"));
         searchRequest.queryCache(request.paramAsBoolean("query_cache", null));
 
         String scroll = request.param("scroll");