Fix getTime field name to time in GetStats (#16894)

CHANGELOG.md

@@ -31,6 +31,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Changes to support IP field in star tree indexing([#16641](https://github.com/opensearch-project/OpenSearch/pull/16641/))
 - Support object fields in star-tree index([#16728](https://github.com/opensearch-project/OpenSearch/pull/16728/))
 - Support searching from doc_value using termQueryCaseInsensitive/termQuery in flat_object/keyword field([#16974](https://github.com/opensearch-project/OpenSearch/pull/16974/))
+- Added a new `time` field to replace the deprecated `getTime` field in `GetStats`. ([#17009](https://github.com/opensearch-project/OpenSearch/pull/17009))
 
 ### Dependencies
 - Bump `com.google.cloud:google-cloud-core-http` from 2.23.0 to 2.47.0 ([#16504](https://github.com/opensearch-project/OpenSearch/pull/16504))
@@ -73,7 +74,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 ### Deprecated
 - Performing update operation with default pipeline or final pipeline is deprecated ([#16712](https://github.com/opensearch-project/OpenSearch/pull/16712))
-
+- Marked `getTime` field as deprecated in favor of the new `time` field. ([#17009](https://github.com/opensearch-project/OpenSearch/pull/17009))
 ### Removed
 
 ### Fixed
@@ -97,7 +98,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Fix Shallow copy snapshot failures on closed index ([#16868](https://github.com/opensearch-project/OpenSearch/pull/16868))
 - Fix multi-value sort for unsigned long ([#16732](https://github.com/opensearch-project/OpenSearch/pull/16732))
 - The `phone-search` analyzer no longer emits the tel/sip prefix, international calling code, extension numbers and unformatted input as a token ([#16993](https://github.com/opensearch-project/OpenSearch/pull/16993))
-
+- Fix `GetStats` field serialization where `getTime` is used instead of `time` ([#17008](https://github.com/opensearch-project/OpenSearch/pull/17009))
 ### Security
 
 [Unreleased 2.x]: https://github.com/opensearch-project/OpenSearch/compare/2.18...2.x

rest-api-spec/src/main/resources/rest-api-spec/test/indices.stats/60_include_both_time_and_gettime_in_stats.yml

@@ -0,0 +1,36 @@
+---
+setup:
+  - do:
+      indices.create:
+        index: test1
+        body:
+          settings:
+            number_of_shards: 1
+            number_of_replicas: 0
+        wait_for_active_shards: all
+
+  - do:
+      index:
+        index: test1
+        id: 1
+        body: { "foo": "bar" }
+
+  - do:
+      indices.refresh:
+        index: test1
+
+---
+"Test _stats API includes both time and getTime metrics with human filter":
+  - skip:
+      version: " - 2.19.99"
+      reason: "this change is added in 3.0.0"
+
+  - do:
+      indices.stats:
+        metric: [ get ]
+        human: true
+
+  - is_true: _all.primaries.get.time
+  - is_true: _all.primaries.get.getTime
+  - match: { _all.primaries.get.time: "0s" }
+  - match: { _all.primaries.get.getTime: "0s" }

server/src/main/java/org/opensearch/index/get/GetStats.java

@@ -41,6 +41,7 @@
 import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
+import java.util.Objects;
 
 /**
  * Stats for a search get
@@ -137,6 +138,7 @@ public long current() {
     public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         builder.startObject(Fields.GET);
         builder.field(Fields.TOTAL, getCount());
+        builder.field(Fields.GET_TIME, Objects.toString(getTime()));
         builder.humanReadableField(Fields.TIME_IN_MILLIS, Fields.TIME, getTime());
         builder.field(Fields.EXISTS_TOTAL, existsCount);
         builder.humanReadableField(Fields.EXISTS_TIME_IN_MILLIS, Fields.EXISTS_TIME, getExistsTime());
@@ -155,7 +157,12 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
     static final class Fields {
         static final String GET = "get";
         static final String TOTAL = "total";
-        static final String TIME = "getTime";
+        /**
+         * Deprecated field name for time. Use {@link #TIME} instead.
+         */
+        @Deprecated(forRemoval = true)
+        static final String GET_TIME = "getTime";
+        static final String TIME = "time";
         static final String TIME_IN_MILLIS = "time_in_millis";
         static final String EXISTS_TOTAL = "exists_total";
         static final String EXISTS_TIME = "exists_time";