From 2f0bf31db994320ae5fbd1b07da371aa86e9bfd0 Mon Sep 17 00:00:00 2001
From: Nathalie Jonathan <143617992+nathaliellenaa@users.noreply.github.com>
Date: Mon, 2 Mar 2026 16:25:10 -0800
Subject: [PATCH] Add msearch `allow_partial_results` flag (#1904)

* Add msearch allow_partial_results flag

Signed-off-by: Nathalie Jonathan <nathhjo@amazon.com>

* Update changelog

Signed-off-by: Nathalie Jonathan <nathhjo@amazon.com>

* Fix compilation failure

Signed-off-by: Nathalie Jonathan <nathhjo@amazon.com>

---------

Signed-off-by: Nathalie Jonathan <nathhjo@amazon.com>
---
 CHANGELOG.md                                  |  1 +
 .../opensearch/core/MsearchRequest.java       | 31 +++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 384a7a6684..c21c13f286 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Bump `com.github.jk1.dependency-license-report` from 3.0.1 to 3.1.1 ([#1895](https://github.com/opensearch-project/opensearch-java/pull/1895), [#1896](https://github.com/opensearch-project/opensearch-java/pull/1896))
 
 ### Added
+- Add msearch `allow_partial_results` flag ([#1904](https://github.com/opensearch-project/opensearch-java/pull/1904))
 
 ### Fixed
 - Fix formatting of the main method to run for various samples ([#1749](https://github.com/opensearch-project/opensearch-java/pull/1749))
diff --git a/java-client/src/main/java/org/opensearch/client/opensearch/core/MsearchRequest.java b/java-client/src/main/java/org/opensearch/client/opensearch/core/MsearchRequest.java
index a417915504..161f22b510 100644
--- a/java-client/src/main/java/org/opensearch/client/opensearch/core/MsearchRequest.java
+++ b/java-client/src/main/java/org/opensearch/client/opensearch/core/MsearchRequest.java
@@ -73,6 +73,9 @@ public class MsearchRequest extends RequestBase implements NdJsonpSerializable,
     @Nullable
     private final Boolean ccsMinimizeRoundtrips;
 
+    @Nullable
+    private final Boolean allowPartialResults;
+
     private final List<ExpandWildcard> expandWildcards;
 
     @Nullable
@@ -104,6 +107,7 @@ private MsearchRequest(Builder builder) {
         this.allowNoIndices = builder.allowNoIndices;
         this.cancelAfterTimeInterval = builder.cancelAfterTimeInterval;
         this.ccsMinimizeRoundtrips = builder.ccsMinimizeRoundtrips;
+        this.allowPartialResults = builder.allowPartialResults;
         this.expandWildcards = ApiTypeHelper.unmodifiable(builder.expandWildcards);
         this.ignoreThrottled = builder.ignoreThrottled;
         this.ignoreUnavailable = builder.ignoreUnavailable;
@@ -161,6 +165,16 @@ public final Boolean ccsMinimizeRoundtrips() {
         return this.ccsMinimizeRoundtrips;
     }
 
+    /**
+     * If true, return partial results if there are shard request timeouts or shard failures.
+     * <p>
+     * API name: {@code allow_partial_results}
+     */
+    @Nullable
+    public final Boolean allowPartialResults() {
+        return this.allowPartialResults;
+    }
+
     /**
      * Type of index that wildcard expressions can match. If the request can target
      * data streams, this argument determines whether wildcard expressions match
@@ -274,6 +288,7 @@ public Builder toBuilder() {
         return new Builder().allowNoIndices(allowNoIndices)
             .cancelAfterTimeInterval(cancelAfterTimeInterval)
             .ccsMinimizeRoundtrips(ccsMinimizeRoundtrips)
+            .allowPartialResults(allowPartialResults)
             .expandWildcards(expandWildcards)
             .ignoreThrottled(ignoreThrottled)
             .ignoreUnavailable(ignoreUnavailable)
@@ -301,6 +316,9 @@ public static class Builder extends ObjectBuilderBase implements ObjectBuilder<M
         @Nullable
         private Boolean ccsMinimizeRoundtrips;
 
+        @Nullable
+        private Boolean allowPartialResults;
+
         @Nullable
         private List<ExpandWildcard> expandWildcards;
 
@@ -373,6 +391,16 @@ public final Builder ccsMinimizeRoundtrips(@Nullable Boolean value) {
             return this;
         }
 
+        /**
+         * If true, return partial results if there are shard request timeouts or shard failures.
+         * <p>
+         * API name: {@code allow_partial_results}
+         */
+        public final Builder allowPartialResults(@Nullable Boolean value) {
+            this.allowPartialResults = value;
+            return this;
+        }
+
         /**
          * Type of index that wildcard expressions can match. If the request can target
          * data streams, this argument determines whether wildcard expressions match
@@ -611,6 +639,9 @@ public MsearchRequest build() {
             if (request.ccsMinimizeRoundtrips != null) {
                 params.put("ccs_minimize_roundtrips", String.valueOf(request.ccsMinimizeRoundtrips));
             }
+            if (request.allowPartialResults != null) {
+                params.put("allow_partial_results", String.valueOf(request.allowPartialResults));
+            }
             return params;
 
         },