Guarantee datasource read api is strong consistent read (opensearch-p…

…roject#1815)

Signed-off-by: Peng Huo <[email protected]>

datasources/src/main/java/org/opensearch/sql/datasources/storage/OpenSearchDataSourceMetadataStorage.java

@@ -217,6 +217,8 @@ private List<DataSourceMetadata> searchInDataSourcesIndex(QueryBuilder query) {
     searchSourceBuilder.query(query);
     searchSourceBuilder.size(DATASOURCE_QUERY_RESULT_SIZE);
     searchRequest.source(searchSourceBuilder);
+    // strongly consistent reads is requred. more info https://github.com/opensearch-project/sql/issues/1801.
+    searchRequest.preference("_primary");
     ActionFuture<SearchResponse> searchResponseActionFuture;
     try (ThreadContext.StoredContext ignored = client.threadPool().getThreadContext()
         .stashContext()) {
@@ -305,4 +307,4 @@ private void handleSigV4PropertiesEncryptionDecryption(Map<String, String> prope
     encryptOrDecrypt(propertiesMap, isEncryption, list);
   }
 
-}
+}