Resolve Alias Issues in Legacy SQL with Filters

integ-test/src/test/java/org/opensearch/sql/legacy/SQLIntegTestCase.java

@@ -462,6 +462,12 @@ protected String makeRequest(String query, int fetch_size) {
     return String.format("{ \"fetch_size\": \"%s\", \"query\": \"%s\" }", fetch_size, query);
   }
 
+  protected String makeRequest(String query, int fetch_size, String filterQuery) {
+    return String.format(
+        "{ \"fetch_size\": \"%s\", \"query\": \"%s\", \"filter\" :  %s }",
+        fetch_size, query, filterQuery);
+  }
+
   protected String makeFetchLessRequest(String query) {
     return String.format("{\n" + "  \"query\": \"%s\"\n" + "}", query);
   }

integ-test/src/test/java/org/opensearch/sql/sql/PaginationIT.java

@@ -7,6 +7,7 @@
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
+import static org.opensearch.sql.legacy.TestUtils.getResponseBody;
 import static org.opensearch.sql.legacy.TestsConstants.TEST_INDEX_CALCS;
 import static org.opensearch.sql.legacy.TestsConstants.TEST_INDEX_ONLINE;
 
@@ -18,6 +19,7 @@
 import org.junit.Test;
 import org.opensearch.client.Request;
 import org.opensearch.client.RequestOptions;
+import org.opensearch.client.Response;
 import org.opensearch.client.ResponseException;
 import org.opensearch.sql.common.setting.Settings;
 import org.opensearch.sql.legacy.SQLIntegTestCase;
@@ -215,4 +217,52 @@ public void testQueryWithoutFrom() {
     assertEquals(1, response.getInt("total"));
     assertEquals(1, response.getJSONArray("datarows").getJSONArray(0).getInt(0));
   }
+
+  @Test
+  public void testAlias() throws Exception {
+    String indexName = Index.ONLINE.getName();
+    String aliasName = "alias_ONLINE";
+    String filterQuery = "{\n" + "  \"term\": {\n" + "    \"107\": 72 \n" + "  }\n" + "}";
+
+    // Execute the SQL query with filter
+    String selectQuery = "SELECT * FROM " + TEST_INDEX_ONLINE;
+    JSONObject initialResponse =
+        new JSONObject(executeFetchQuery(selectQuery, 10, "jdbc", filterQuery));
+    assertEquals(initialResponse.getInt("size"), 10);
+
+    // Create an alias
+    String createAliasQuery =
+        String.format(
+            "{ \"actions\": [ { \"add\": { \"index\": \"%s\", \"alias\": \"%s\" } } ] }",
+            indexName, aliasName);
+    Request createAliasRequest = new Request("POST", "/_aliases");
+    createAliasRequest.setJsonEntity(createAliasQuery);
+    JSONObject aliasResponse = new JSONObject(executeRequest(createAliasRequest));
+
+    // Assert that alias creation was acknowledged
+    assertTrue(aliasResponse.getBoolean("acknowledged"));
+
+    // Query using the alias
+    String aliasSelectQuery = String.format("SELECT * FROM %s", aliasName);
+    JSONObject aliasQueryResponse = new JSONObject(executeFetchQuery(aliasSelectQuery, 4, "jdbc"));
+    assertEquals(4, aliasQueryResponse.getInt("size"));
+
+    // Query using the alias with filter
+    JSONObject aliasFilteredResponse =
+        new JSONObject(executeFetchQuery(aliasSelectQuery, 4, "jdbc", filterQuery));
+    assertEquals(aliasFilteredResponse.getInt("size"), 4);
+  }
+
+  private String executeFetchQuery(String query, int fetchSize, String requestType, String filter)
+      throws IOException {
+    String endpoint = "/_plugins/_sql?format=" + requestType;
+    String requestBody = makeRequest(query, fetchSize, filter);
+
+    Request sqlRequest = new Request("POST", endpoint);
+    sqlRequest.setJsonEntity(requestBody);
+
+    Response response = client().performRequest(sqlRequest);
+    String responseString = getResponseBody(response, true);
+    return responseString;
+  }
 }

legacy/src/main/java/org/opensearch/sql/legacy/executor/format/SelectResultSet.java

@@ -26,6 +26,8 @@
 import java.util.stream.StreamSupport;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.opensearch.action.admin.indices.alias.get.GetAliasesRequest;
+import org.opensearch.action.admin.indices.alias.get.GetAliasesResponse;
 import org.opensearch.action.admin.indices.mapping.get.GetFieldMappingsRequest;
 import org.opensearch.action.admin.indices.mapping.get.GetFieldMappingsResponse;
 import org.opensearch.action.search.ClearScrollResponse;
@@ -164,7 +166,11 @@ private void populateResultSetFromDefaultCursor(DefaultCursor cursor) {
   private void loadFromEsState(Query query) {
     String indexName = fetchIndexName(query);
     String[] fieldNames = fetchFieldsAsArray(query);
-
+    GetAliasesResponse getAliasesResponse =
+        client.admin().indices().getAliases(new GetAliasesRequest(indexName)).actionGet();
+    if (getAliasesResponse != null && !getAliasesResponse.getAliases().isEmpty()) {
+      indexName = getAliasesResponse.getAliases().keySet().iterator().next();
+    }
     // Reset boolean in the case of JOIN query where multiple calls to loadFromEsState() are made
     selectAll = isSimpleQuerySelectAll(query) || isJoinQuerySelectAll(query, fieldNames);