chore: Update product name in JDBC metadata for PG dialect

Author: sakthivelmanii

src/main/java/com/google/cloud/spanner/jdbc/JdbcDatabaseMetaData.java

@@ -48,6 +48,7 @@ class JdbcDatabaseMetaData extends AbstractJdbcWrapper implements DatabaseMetaDa
   private static final int DATABASE_MAJOR_VERSION = 1;
   private static final int DATABASE_MINOR_VERSION = 0;
   private static final String PRODUCT_NAME = "Google Cloud Spanner";
+  private static final String POSTGRESQL_PRODUCT_NAME = PRODUCT_NAME + " PostgreSQL";
 
   @VisibleForTesting
   static String readSqlFromFile(String filename, Dialect dialect) {
@@ -137,7 +138,7 @@ public boolean nullsAreSortedAtEnd() {
 
   @Override
   public String getDatabaseProductName() {
-    return PRODUCT_NAME;
+    return connection.getDialect() == Dialect.POSTGRESQL ? POSTGRESQL_PRODUCT_NAME : PRODUCT_NAME;
   }
 
   @Override

src/test/java/com/google/cloud/spanner/jdbc/JdbcDatabaseMetaDataTest.java

@@ -57,6 +57,8 @@ public static Object[] data() {
   private static final int DATABASE_MAJOR_VERSION = 1;
   private static final int DATABASE_MINOR_VERSION = 0;
   private static final String DATABASE_PRODUCT_NAME = "Google Cloud Spanner";
+  private static final String POSTGRESQL_DATABASE_PRODUCT_NAME =
+      DATABASE_PRODUCT_NAME + " PostgreSQL";
 
   @Test
   public void testTrivialMethods() throws SQLException {
@@ -90,7 +92,6 @@ public void testTrivialMethods() throws SQLException {
     assertEquals("CATALOG", meta.getCatalogTerm());
     assertEquals(DATABASE_MAJOR_VERSION, meta.getDatabaseMajorVersion());
     assertEquals(DATABASE_MINOR_VERSION, meta.getDatabaseMinorVersion());
-    assertEquals(DATABASE_PRODUCT_NAME, meta.getDatabaseProductName());
     assertEquals(
         DATABASE_MAJOR_VERSION + "." + DATABASE_MINOR_VERSION, meta.getDatabaseProductVersion());
     assertEquals(Connection.TRANSACTION_SERIALIZABLE, meta.getDefaultTransactionIsolation());
@@ -134,8 +135,10 @@ public void testTrivialMethods() throws SQLException {
     assertFalse(meta.isCatalogAtStart());
     assertEquals(connection.isReadOnly(), meta.isReadOnly());
     if (dialect == Dialect.POSTGRESQL) {
+      assertEquals(POSTGRESQL_DATABASE_PRODUCT_NAME, meta.getDatabaseProductName());
       assertTrue(meta.storesLowerCaseIdentifiers());
     } else {
+      assertEquals(DATABASE_PRODUCT_NAME, meta.getDatabaseProductName());
       assertFalse(meta.storesLowerCaseIdentifiers());
     }
     assertFalse(meta.storesLowerCaseQuotedIdentifiers());