Bug Fix, close scroll context

build.sbt

@@ -113,7 +113,10 @@ lazy val integtest = (project in file("integ-test"))
       "org.scalactic" %% "scalactic" % "3.2.15",
       "org.scalatest" %% "scalatest" % "3.2.15" % "test",
       "com.stephenn" %% "scalatest-json-jsonassert" % "0.2.5" % "test",
-      "org.testcontainers" % "testcontainers" % "1.18.0" % "test"),
+      "org.testcontainers" % "testcontainers" % "1.18.0" % "test",
+      // add opensearch-java client to get node stats
+      "org.opensearch.client" % "opensearch-java" % "2.6.0" % "test"
+        exclude ("com.fasterxml.jackson.core", "jackson-databind")),
     libraryDependencies ++= deps(sparkVersion),
     Test / fullClasspath += (flintSparkIntegration / assembly).value)
 
@@ -130,8 +133,7 @@ lazy val sparkSqlApplication = (project in file("spark-sql-application"))
     commonSettings,
     name := "sql-job",
     scalaVersion := scala212,
-    libraryDependencies ++= Seq(
-      "org.scalatest" %% "scalatest" % "3.2.15" % "test"),
+    libraryDependencies ++= Seq("org.scalatest" %% "scalatest" % "3.2.15" % "test"),
     libraryDependencies ++= deps(sparkVersion))
 
 lazy val sparkSqlApplicationCosmetic = project

flint-core/src/main/scala/org/opensearch/flint/core/storage/OpenSearchScrollReader.java

@@ -54,7 +54,7 @@ SearchResponse search(SearchRequest request) throws IOException {
    * clean the scroll context.
    */
   void clean() throws IOException {
-    if (Strings.isNullOrEmpty(scrollId)) {
+    if (!Strings.isNullOrEmpty(scrollId)) {
       ClearScrollRequest clearScrollRequest = new ClearScrollRequest();
       clearScrollRequest.addScrollId(scrollId);
       client.clearScroll(clearScrollRequest, RequestOptions.DEFAULT);

integ-test/src/test/scala/org/opensearch/flint/core/FlintOpenSearchClientSuite.scala

@@ -8,6 +8,9 @@ package org.opensearch.flint.core
 import scala.collection.JavaConverters._
 
 import com.stephenn.scalatest.jsonassert.JsonMatchers.matchJson
+import org.opensearch.client.json.jackson.JacksonJsonpMapper
+import org.opensearch.client.opensearch.OpenSearchClient
+import org.opensearch.client.transport.rest_client.RestClientTransport
 import org.opensearch.flint.OpenSearchSuite
 import org.opensearch.flint.core.metadata.FlintMetadata
 import org.opensearch.flint.core.storage.FlintOpenSearchClient
@@ -92,4 +95,30 @@ class FlintOpenSearchClientSuite extends AnyFlatSpec with OpenSearchSuite with M
       reader.close()
     }
   }
+
+  it should "scroll context close properly after read" in {
+    val indexName = "t0001"
+    withIndexName(indexName) {
+      simpleIndex(indexName)
+      val match_all = null
+      val reader = flintClient.createReader(indexName, match_all)
+
+      reader.hasNext shouldBe true
+      reader.next shouldBe """{"accountId":"123","eventName":"event","eventSource":"source"}"""
+      reader.hasNext shouldBe false
+      reader.close()
+
+      scrollShouldClosed()
+    }
+  }
+
+  def scrollShouldClosed(): Unit = {
+    val transport =
+      new RestClientTransport(openSearchClient.getLowLevelClient, new JacksonJsonpMapper)
+    val client = new OpenSearchClient(transport)
+
+    val response = client.nodes().stats()
+    response.nodes().size() should be > 0
+    response.nodes().forEach((_, stats) => stats.indices().search().scrollCurrent() shouldBe 0)
+  }
 }