diff --git a/output/schema/schema.json b/output/schema/schema.json
index 6fe077a875..f36ce3d0ba 100644
--- a/output/schema/schema.json
+++ b/output/schema/schema.json
@@ -50375,7 +50375,7 @@
         "name": "AggregateName",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L142-L146",
+      "specLocation": "_types/common.ts#L144-L148",
       "type": {
         "kind": "instance_of",
         "type": {
@@ -50573,7 +50573,7 @@
         "name": "ByteSize",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L90-L91",
+      "specLocation": "_types/common.ts#L92-L93",
       "type": {
         "kind": "union_of",
         "items": [
@@ -50626,7 +50626,7 @@
         "name": "Bytes",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L166-L178"
+      "specLocation": "_types/common.ts#L168-L180"
     },
     {
       "kind": "type_alias",
@@ -50769,7 +50769,7 @@
         "name": "ClusterInfoTarget",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L380-L386"
+      "specLocation": "_types/common.ts#L382-L388"
     },
     {
       "kind": "type_alias",
@@ -50777,7 +50777,7 @@
         "name": "ClusterInfoTargets",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L388-L388",
+      "specLocation": "_types/common.ts#L390-L390",
       "type": {
         "kind": "union_of",
         "items": [
@@ -50996,7 +50996,7 @@
         "name": "Conflicts",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L180-L189"
+      "specLocation": "_types/common.ts#L182-L191"
     },
     {
       "kind": "interface",
@@ -51127,7 +51127,7 @@
         "name": "DataStreamName",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L86-L86",
+      "specLocation": "_types/common.ts#L88-L88",
       "type": {
         "kind": "instance_of",
         "type": {
@@ -51142,7 +51142,7 @@
         "name": "DataStreamNames",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L88-L88",
+      "specLocation": "_types/common.ts#L90-L90",
       "type": {
         "kind": "union_of",
         "items": [
@@ -51603,7 +51603,7 @@
         "namespace": "_types"
       },
       "properties": [],
-      "specLocation": "_types/common.ts#L157-L158"
+      "specLocation": "_types/common.ts#L159-L160"
     },
     {
       "kind": "type_alias",
@@ -51812,7 +51812,7 @@
         "name": "ExpandWildcard",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L198-L212"
+      "specLocation": "_types/common.ts#L200-L214"
     },
     {
       "kind": "type_alias",
@@ -51820,7 +51820,7 @@
         "name": "ExpandWildcards",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L214-L214",
+      "specLocation": "_types/common.ts#L216-L216",
       "type": {
         "kind": "union_of",
         "items": [
@@ -51851,7 +51851,7 @@
         "name": "Field",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L135-L136",
+      "specLocation": "_types/common.ts#L137-L138",
       "type": {
         "kind": "instance_of",
         "type": {
@@ -52172,7 +52172,7 @@
         "name": "Fields",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L137-L137",
+      "specLocation": "_types/common.ts#L139-L139",
       "type": {
         "kind": "union_of",
         "items": [
@@ -52267,7 +52267,7 @@
         "name": "Fuzziness",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L130-L131",
+      "specLocation": "_types/common.ts#L132-L133",
       "type": {
         "kind": "union_of",
         "items": [
@@ -52971,7 +52971,7 @@
         "name": "GrokPattern",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L81-L81",
+      "specLocation": "_types/common.ts#L83-L83",
       "type": {
         "kind": "instance_of",
         "type": {
@@ -53015,7 +53015,7 @@
         "name": "HealthStatus",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L216-L238"
+      "specLocation": "_types/common.ts#L218-L240"
     },
     {
       "kind": "type_alias",
@@ -53038,7 +53038,7 @@
         "name": "HttpHeaders",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L155-L155",
+      "specLocation": "_types/common.ts#L157-L157",
       "type": {
         "kind": "dictionary_of",
         "key": {
@@ -53537,7 +53537,7 @@
           }
         }
       ],
-      "specLocation": "_types/common.ts#L334-L361"
+      "specLocation": "_types/common.ts#L336-L363"
     },
     {
       "kind": "interface",
@@ -53680,7 +53680,7 @@
           }
         }
       ],
-      "specLocation": "_types/common.ts#L319-L332"
+      "specLocation": "_types/common.ts#L321-L334"
     },
     {
       "kind": "interface",
@@ -54185,7 +54185,7 @@
         "name": "Level",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L248-L252"
+      "specLocation": "_types/common.ts#L250-L254"
     },
     {
       "kind": "enum",
@@ -54518,7 +54518,7 @@
         "name": "Metadata",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L93-L93",
+      "specLocation": "_types/common.ts#L95-L95",
       "type": {
         "kind": "dictionary_of",
         "key": {
@@ -54573,7 +54573,7 @@
         "name": "MinimumShouldMatch",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L160-L164",
+      "specLocation": "_types/common.ts#L162-L166",
       "type": {
         "kind": "union_of",
         "items": [
@@ -54602,7 +54602,7 @@
         "name": "MultiTermQueryRewrite",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L132-L133",
+      "specLocation": "_types/common.ts#L134-L135",
       "type": {
         "kind": "instance_of",
         "type": {
@@ -54617,7 +54617,7 @@
         "name": "Name",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L74-L74",
+      "specLocation": "_types/common.ts#L76-L76",
       "type": {
         "kind": "instance_of",
         "type": {
@@ -54632,7 +54632,7 @@
         "name": "Names",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L75-L75",
+      "specLocation": "_types/common.ts#L77-L77",
       "type": {
         "kind": "union_of",
         "items": [
@@ -54662,7 +54662,7 @@
         "name": "Namespace",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L77-L77",
+      "specLocation": "_types/common.ts#L79-L79",
       "type": {
         "kind": "instance_of",
         "type": {
@@ -54859,7 +54859,7 @@
         "name": "NodeName",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L83-L84",
+      "specLocation": "_types/common.ts#L85-L86",
       "type": {
         "kind": "instance_of",
         "type": {
@@ -55196,7 +55196,7 @@
         "name": "OpType",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L254-L263"
+      "specLocation": "_types/common.ts#L256-L265"
     },
     {
       "kind": "type_alias",
@@ -55204,7 +55204,7 @@
         "name": "Password",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L192-L192",
+      "specLocation": "_types/common.ts#L194-L194",
       "type": {
         "kind": "instance_of",
         "type": {
@@ -55313,7 +55313,7 @@
         "name": "PipelineName",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L80-L80",
+      "specLocation": "_types/common.ts#L82-L82",
       "type": {
         "kind": "instance_of",
         "type": {
@@ -55434,13 +55434,28 @@
       ],
       "specLocation": "_types/Stats.ts#L207-L217"
     },
+    {
+      "kind": "type_alias",
+      "name": {
+        "name": "ProjectRouting",
+        "namespace": "_types"
+      },
+      "specLocation": "_types/common.ts#L74-L74",
+      "type": {
+        "kind": "instance_of",
+        "type": {
+          "name": "string",
+          "namespace": "_builtins"
+        }
+      }
+    },
     {
       "kind": "type_alias",
       "name": {
         "name": "PropertyName",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L127-L127",
+      "specLocation": "_types/common.ts#L129-L129",
       "type": {
         "kind": "instance_of",
         "type": {
@@ -55792,7 +55807,7 @@
         "name": "Refresh",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L265-L272"
+      "specLocation": "_types/common.ts#L267-L274"
     },
     {
       "kind": "interface",
@@ -55894,7 +55909,7 @@
         "name": "RelationName",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L128-L128",
+      "specLocation": "_types/common.ts#L130-L130",
       "type": {
         "kind": "instance_of",
         "type": {
@@ -57225,7 +57240,7 @@
         "name": "SearchType",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L274-L279"
+      "specLocation": "_types/common.ts#L276-L281"
     },
     {
       "kind": "interface",
@@ -57530,7 +57545,7 @@
         "name": "SequenceNumber",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L125-L125",
+      "specLocation": "_types/common.ts#L127-L127",
       "type": {
         "kind": "instance_of",
         "type": {
@@ -57545,7 +57560,7 @@
         "name": "Service",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L78-L78",
+      "specLocation": "_types/common.ts#L80-L80",
       "type": {
         "kind": "instance_of",
         "type": {
@@ -57785,7 +57800,7 @@
         "name": "Slices",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L363-L368",
+      "specLocation": "_types/common.ts#L365-L370",
       "type": {
         "kind": "union_of",
         "items": [
@@ -57818,7 +57833,7 @@
         "name": "SlicesCalculation",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L370-L378"
+      "specLocation": "_types/common.ts#L372-L380"
     },
     {
       "kind": "type_alias",
@@ -58313,7 +58328,7 @@
         "name": "SuggestMode",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L281-L294"
+      "specLocation": "_types/common.ts#L283-L296"
     },
     {
       "kind": "type_alias",
@@ -58322,7 +58337,7 @@
         "name": "SuggestionName",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L148-L152",
+      "specLocation": "_types/common.ts#L150-L154",
       "type": {
         "kind": "instance_of",
         "type": {
@@ -58391,7 +58406,7 @@
         "name": "TaskId",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L129-L129",
+      "specLocation": "_types/common.ts#L131-L131",
       "type": {
         "kind": "instance_of",
         "type": {
@@ -58531,7 +58546,7 @@
         "name": "ThreadType",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L296-L302"
+      "specLocation": "_types/common.ts#L298-L304"
     },
     {
       "kind": "type_alias",
@@ -58936,7 +58951,7 @@
         "name": "Username",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L191-L191",
+      "specLocation": "_types/common.ts#L193-L193",
       "type": {
         "kind": "instance_of",
         "type": {
@@ -58951,7 +58966,7 @@
         "name": "Uuid",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L122-L122",
+      "specLocation": "_types/common.ts#L124-L124",
       "type": {
         "kind": "instance_of",
         "type": {
@@ -58966,7 +58981,7 @@
         "name": "VersionNumber",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L96-L96",
+      "specLocation": "_types/common.ts#L98-L98",
       "type": {
         "kind": "instance_of",
         "type": {
@@ -58981,7 +58996,7 @@
         "name": "VersionString",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L98-L98",
+      "specLocation": "_types/common.ts#L100-L100",
       "type": {
         "kind": "instance_of",
         "type": {
@@ -59014,7 +59029,7 @@
         "name": "VersionType",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L100-L119"
+      "specLocation": "_types/common.ts#L102-L121"
     },
     {
       "kind": "enum",
@@ -59030,7 +59045,7 @@
         "name": "WaitForActiveShardOptions",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L304-L308"
+      "specLocation": "_types/common.ts#L306-L310"
     },
     {
       "kind": "type_alias",
@@ -59042,7 +59057,7 @@
         "name": "WaitForActiveShards",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L139-L140",
+      "specLocation": "_types/common.ts#L141-L142",
       "type": {
         "kind": "union_of",
         "items": [
@@ -59089,7 +59104,7 @@
         "name": "WaitForEvents",
         "namespace": "_types"
       },
-      "specLocation": "_types/common.ts#L310-L317"
+      "specLocation": "_types/common.ts#L312-L319"
     },
     {
       "kind": "interface",
@@ -192876,7 +192891,7 @@
           }
         }
       ],
-      "specLocation": "ml/_types/Datafeed.ts#L254-L267"
+      "specLocation": "ml/_types/Datafeed.ts#L260-L273"
     },
     {
       "kind": "enum",
@@ -192895,7 +192910,7 @@
         "name": "ChunkingMode",
         "namespace": "ml._types"
       },
-      "specLocation": "ml/_types/Datafeed.ts#L248-L252"
+      "specLocation": "ml/_types/Datafeed.ts#L254-L258"
     },
     {
       "kind": "interface",
@@ -193735,6 +193750,24 @@
             }
           }
         },
+        {
+          "availability": {
+            "serverless": {},
+            "stack": {
+              "since": "9.2.0"
+            }
+          },
+          "description": "The specified projects when querying the source indices.",
+          "name": "project_routing",
+          "required": false,
+          "type": {
+            "kind": "instance_of",
+            "type": {
+              "name": "ProjectRouting",
+              "namespace": "_types"
+            }
+          }
+        },
         {
           "name": "job_id",
           "required": false,
@@ -193831,7 +193864,7 @@
           }
         }
       ],
-      "specLocation": "ml/_types/Datafeed.ts#L66-L123"
+      "specLocation": "ml/_types/Datafeed.ts#L66-L129"
     },
     {
       "kind": "interface",
@@ -193877,7 +193910,7 @@
           }
         }
       ],
-      "specLocation": "ml/_types/Datafeed.ts#L213-L227"
+      "specLocation": "ml/_types/Datafeed.ts#L219-L233"
     },
     {
       "kind": "enum",
@@ -193899,7 +193932,7 @@
         "name": "DatafeedState",
         "namespace": "ml._types"
       },
-      "specLocation": "ml/_types/Datafeed.ts#L139-L144"
+      "specLocation": "ml/_types/Datafeed.ts#L145-L150"
     },
     {
       "kind": "interface",
@@ -193984,7 +194017,7 @@
           }
         }
       ],
-      "specLocation": "ml/_types/Datafeed.ts#L146-L175"
+      "specLocation": "ml/_types/Datafeed.ts#L152-L181"
     },
     {
       "kind": "interface",
@@ -194104,7 +194137,7 @@
           }
         }
       ],
-      "specLocation": "ml/_types/Datafeed.ts#L177-L205"
+      "specLocation": "ml/_types/Datafeed.ts#L183-L211"
     },
     {
       "kind": "interface",
@@ -196366,7 +196399,7 @@
           }
         }
       ],
-      "specLocation": "ml/_types/Datafeed.ts#L125-L136"
+      "specLocation": "ml/_types/Datafeed.ts#L131-L142"
     },
     {
       "kind": "enum",
@@ -197137,7 +197170,7 @@
           }
         }
       ],
-      "specLocation": "ml/_types/Datafeed.ts#L207-L211"
+      "specLocation": "ml/_types/Datafeed.ts#L213-L217"
     },
     {
       "kind": "type_alias",
@@ -201105,7 +201138,7 @@
           }
         }
       ],
-      "specLocation": "ml/_types/Datafeed.ts#L229-L246"
+      "specLocation": "ml/_types/Datafeed.ts#L235-L252"
     },
     {
       "kind": "enum",
@@ -213241,6 +213274,24 @@
               }
             }
           },
+          {
+            "availability": {
+              "serverless": {},
+              "stack": {
+                "since": "9.2.0"
+              }
+            },
+            "description": "The specified projects when querying the source indices.",
+            "name": "project_routing",
+            "required": false,
+            "type": {
+              "kind": "instance_of",
+              "type": {
+                "name": "ProjectRouting",
+                "namespace": "_types"
+              }
+            }
+          },
           {
             "description": "Identifier for the anomaly detection job.",
             "name": "job_id",
@@ -213473,7 +213524,7 @@
           }
         }
       ],
-      "specLocation": "ml/put_datafeed/MlPutDatafeedRequest.ts#L37-L184"
+      "specLocation": "ml/put_datafeed/MlPutDatafeedRequest.ts#L38-L191"
     },
     {
       "kind": "response",
@@ -264451,6 +264502,24 @@
             }
           }
         },
+        {
+          "availability": {
+            "serverless": {},
+            "stack": {
+              "since": "9.2.0"
+            }
+          },
+          "description": "The specified projects when querying the source indices.",
+          "name": "project_routing",
+          "required": false,
+          "type": {
+            "kind": "instance_of",
+            "type": {
+              "name": "ProjectRouting",
+              "namespace": "_types"
+            }
+          }
+        },
         {
           "description": "A query clause that retrieves a subset of data from the source index.",
           "name": "query",
@@ -264482,7 +264551,7 @@
           }
         }
       ],
-      "specLocation": "transform/_types/Transform.ts#L146-L165"
+      "specLocation": "transform/_types/Transform.ts#L146-L171"
     },
     {
       "kind": "interface",
@@ -264504,7 +264573,7 @@
           }
         }
       ],
-      "specLocation": "transform/_types/Transform.ts#L169-L175",
+      "specLocation": "transform/_types/Transform.ts#L175-L181",
       "variants": {
         "kind": "container"
       }
@@ -264542,7 +264611,7 @@
           }
         }
       ],
-      "specLocation": "transform/_types/Transform.ts#L177-L189"
+      "specLocation": "transform/_types/Transform.ts#L183-L195"
     },
     {
       "kind": "request",
diff --git a/output/typescript/types.ts b/output/typescript/types.ts
index 88677a4cf4..cc0adf9049 100644
--- a/output/typescript/types.ts
+++ b/output/typescript/types.ts
@@ -2674,6 +2674,8 @@ export interface PluginStats {
   licensed: boolean
 }
 
+export type ProjectRouting = string
+
 export type PropertyName = string
 
 export interface QueryCacheStats {
@@ -16009,6 +16011,7 @@ export interface MlDatafeedConfig {
   indices?: Indices
   indexes?: Indices
   indices_options?: IndicesOptions
+  project_routing?: ProjectRouting
   job_id?: Id
   max_empty_searches?: integer
   query?: QueryDslQueryContainer
@@ -17902,6 +17905,7 @@ export interface MlPutDatafeedRequest extends RequestBase {
     indices?: Indices
     indexes?: Indices
     indices_options?: IndicesOptions
+    project_routing?: ProjectRouting
     job_id?: Id
     max_empty_searches?: integer
     query?: QueryDslQueryContainer
@@ -22383,6 +22387,7 @@ export interface TransformSettings {
 
 export interface TransformSource {
   index: Indices
+  project_routing?: ProjectRouting
   query?: QueryDslQueryContainer
   runtime_mappings?: MappingRuntimeFields
 }
diff --git a/specification/_types/common.ts b/specification/_types/common.ts
index 829996095b..972046f78b 100644
--- a/specification/_types/common.ts
+++ b/specification/_types/common.ts
@@ -71,6 +71,8 @@ export type Metrics = string | string[]
 
 export type ClusterAlias = string
 
+export type ProjectRouting = string
+
 export type Name = string
 export type Names = Name | Name[]
 
diff --git a/specification/ml/_types/Datafeed.ts b/specification/ml/_types/Datafeed.ts
index bed5f5ea35..dd63d86ae1 100644
--- a/specification/ml/_types/Datafeed.ts
+++ b/specification/ml/_types/Datafeed.ts
@@ -18,7 +18,7 @@
  */
 
 import { AggregationContainer } from '@_types/aggregations/AggregationContainer'
-import { Id, Indices, IndicesOptions } from '@_types/common'
+import { Id, Indices, IndicesOptions, ProjectRouting } from '@_types/common'
 import { RuntimeFields } from '@_types/mapping/RuntimeFields'
 import { integer, long } from '@_types/Numeric'
 import { QueryContainer } from '@_types/query_dsl/abstractions'
@@ -94,6 +94,12 @@ export class DatafeedConfig {
    * Specifies index expansion options that are used during search.
    */
   indices_options?: IndicesOptions
+  /**
+   * The specified projects when querying the source indices.
+   * @availability stack since=9.2.0
+   * @availability serverless
+   */
+  project_routing?: ProjectRouting
   job_id?: Id
   /**
    * If a real-time datafeed has never seen any data (including during any initial training period) then it will automatically stop itself and close its associated job after this many real-time searches that return no documents. In other words, it will stop after `frequency` times `max_empty_searches` of real-time operation. If not set then a datafeed with no end time that sees no data will remain started until it is explicitly stopped.
diff --git a/specification/ml/put_datafeed/MlPutDatafeedRequest.ts b/specification/ml/put_datafeed/MlPutDatafeedRequest.ts
index a0b646db70..746aeed7f9 100644
--- a/specification/ml/put_datafeed/MlPutDatafeedRequest.ts
+++ b/specification/ml/put_datafeed/MlPutDatafeedRequest.ts
@@ -24,7 +24,8 @@ import {
   HttpHeaders,
   Id,
   Indices,
-  IndicesOptions
+  IndicesOptions,
+  ProjectRouting
 } from '@_types/common'
 import { RuntimeFields } from '@_types/mapping/RuntimeFields'
 import { integer } from '@_types/Numeric'
@@ -135,6 +136,12 @@ export interface Request extends RequestBase {
      * Specifies index expansion options that are used during search
      */
     indices_options?: IndicesOptions
+    /**
+     * The specified projects when querying the source indices.
+     * @availability stack since=9.2.0
+     * @availability serverless
+     * */
+    project_routing?: ProjectRouting
     /**
      * Identifier for the anomaly detection job.
      */
diff --git a/specification/transform/_types/Transform.ts b/specification/transform/_types/Transform.ts
index ed11e0bcb1..b65387757d 100644
--- a/specification/transform/_types/Transform.ts
+++ b/specification/transform/_types/Transform.ts
@@ -24,7 +24,7 @@ import {
   HistogramAggregation,
   TermsAggregation
 } from '@_types/aggregations/bucket'
-import { Field, IndexName, Indices } from '@_types/common'
+import { Field, IndexName, Indices, ProjectRouting } from '@_types/common'
 import { RuntimeFields } from '@_types/mapping/RuntimeFields'
 import { float, integer } from '@_types/Numeric'
 import { QueryContainer } from '@_types/query_dsl/abstractions'
@@ -151,6 +151,12 @@ export class Source {
    * any indices are in remote clusters then the master node and at least one transform node must have the `remote_cluster_client` node role.
    */
   index: Indices
+  /**
+   * The specified projects when querying the source indices.
+   * @availability stack since=9.2.0
+   * @availability serverless
+   */
+  project_routing?: ProjectRouting
   /**
    * A query clause that retrieves a subset of data from the source index.
    */