@@ -108,6 +108,8 @@
 * <li>maxSessions (int): Sets the maximum number of sessions in the backing session pool.
 * Defaults to 400.
 * <li>numChannels (int): Sets the number of gRPC channels to use. Defaults to 4.
+* <li>rpcPriority (String): Sets the priority for all RPC invocations from this connection.
+* Defaults to HIGH.
 * </ul>
 */
 public class JdbcDriver implements Driver {

@@ -51,6 +51,12 @@ public void testDefaultOptions() throws SQLException {
 assertThat(rs.getString("OPTIMIZER_STATISTICS_PACKAGE")).isEqualTo("");
 assertThat(rs.next()).isFalse();
 }
+try (java.sql.ResultSet rs =
+connection.createStatement().executeQuery("SHOW VARIABLE RPC_PRIORITY")) {
+assertThat(rs.next()).isTrue();
+assertThat(rs.getString("RPC_PRIORITY")).isEqualTo("PRIORITY_UNSPECIFIED");
+assertThat(rs.next()).isFalse();
+}
 }
 }
 
@@ -59,8 +65,8 @@ public void testOptionsInConnectionUrl() throws SQLException {
 try (java.sql.Connection connection =
 DriverManager.getConnection(
 String.format(
-"jdbc:%s;optimizerVersion=%s;optimizerStatisticsPackage=%s",
-getBaseUrl(), "100", "url_package"))) {
+"jdbc:%s;optimizerVersion=%s;optimizerStatisticsPackage=%s;rpcPriority=%s",
+getBaseUrl(), "100", "url_package", "LOW"))) {
 try (java.sql.ResultSet rs =
 connection.createStatement().executeQuery("SHOW VARIABLE OPTIMIZER_VERSION")) {
 assertThat(rs.next()).isTrue();
@@ -73,6 +79,12 @@ public void testOptionsInConnectionUrl() throws SQLException {
 assertThat(rs.getString("OPTIMIZER_STATISTICS_PACKAGE")).isEqualTo("url_package");
 assertThat(rs.next()).isFalse();
 }
+try (java.sql.ResultSet rs =
+connection.createStatement().executeQuery("SHOW VARIABLE RPC_PRIORITY")) {
+assertThat(rs.next()).isTrue();
+assertThat(rs.getString("RPC_PRIORITY")).isEqualTo("LOW");
+assertThat(rs.next()).isFalse();
+}
 }
 }
 
@@ -122,6 +134,28 @@ public void testSetOptions() throws SQLException {
 assertThat(rs.getString("OPTIMIZER_STATISTICS_PACKAGE")).isEqualTo("");
 assertThat(rs.next()).isFalse();
 }
+
+connection.createStatement().execute("SET RPC_PRIORITY='LOW'");
+try (java.sql.ResultSet rs =
+connection.createStatement().executeQuery("SHOW VARIABLE RPC_PRIORITY")) {
+assertThat(rs.next()).isTrue();
+assertThat(rs.getString("RPC_PRIORITY")).isEqualTo("LOW");
+assertThat(rs.next()).isFalse();
+}
+connection.createStatement().execute("SET RPC_PRIORITY='MEDIUM'");
+try (java.sql.ResultSet rs =
+connection.createStatement().executeQuery("SHOW VARIABLE RPC_PRIORITY")) {
+assertThat(rs.next()).isTrue();
+assertThat(rs.getString("RPC_PRIORITY")).isEqualTo("MEDIUM");
+assertThat(rs.next()).isFalse();
+}
+connection.createStatement().execute("SET RPC_PRIORITY='NULL'");
+try (java.sql.ResultSet rs =
+connection.createStatement().executeQuery("SHOW VARIABLE RPC_PRIORITY")) {
+assertThat(rs.next()).isTrue();
+assertThat(rs.getString("RPC_PRIORITY")).isEqualTo("PRIORITY_UNSPECIFIED");
+assertThat(rs.next()).isFalse();
+}
 }
 }
 
@@ -130,6 +164,7 @@ public void testSetAndUseOptions() throws SQLException {
 try (java.sql.Connection connection = createJdbcConnection()) {
 connection.createStatement().execute("SET OPTIMIZER_VERSION='20'");
 connection.createStatement().execute("SET OPTIMIZER_STATISTICS_PACKAGE='20210609'");
+connection.createStatement().execute("SET RPC_PRIORITY='LOW'");
 try (java.sql.ResultSet rs =
 connection.createStatement().executeQuery(SELECT_COUNT_STATEMENT.getSql())) {
 assertThat(rs.next()).isTrue();
@@ -140,10 +175,12 @@ public void testSetAndUseOptions() throws SQLException {
 ExecuteSqlRequest request = getLastExecuteSqlRequest();
 assertThat(request.getQueryOptions().getOptimizerVersion()).isEqualTo("20");
 assertThat(request.getQueryOptions().getOptimizerStatisticsPackage()).isEqualTo("20210609");
+assertThat(request.getRequestOptions().getPriority().toString()).isEqualTo("PRIORITY_LOW");
 }
 
 connection.createStatement().execute("SET OPTIMIZER_VERSION='latest'");
 connection.createStatement().execute("SET OPTIMIZER_STATISTICS_PACKAGE='latest'");
+connection.createStatement().execute("SET RPC_PRIORITY='MEDIUM'");
 try (java.sql.ResultSet rs =
 connection.createStatement().executeQuery(SELECT_COUNT_STATEMENT.getSql())) {
 assertThat(rs.next()).isTrue();
@@ -152,12 +189,15 @@ public void testSetAndUseOptions() throws SQLException {
 ExecuteSqlRequest request = getLastExecuteSqlRequest();
 assertThat(request.getQueryOptions().getOptimizerVersion()).isEqualTo("latest");
 assertThat(request.getQueryOptions().getOptimizerStatisticsPackage()).isEqualTo("latest");
+assertThat(request.getRequestOptions().getPriority().toString())
+.isEqualTo("PRIORITY_MEDIUM");
 }
 
 // Set the options to ''. This will do a fallback to the default, meaning that it will be read
 // from the environment variables as we have nothing set on the connection URL.
 connection.createStatement().execute("SET OPTIMIZER_VERSION=''");
 connection.createStatement().execute("SET OPTIMIZER_STATISTICS_PACKAGE=''");
+connection.createStatement().execute("SET RPC_PRIORITY='NULL'");
 try (java.sql.ResultSet rs =
 connection.createStatement().executeQuery(SELECT_COUNT_STATEMENT.getSql())) {
 assertThat(rs.next()).isTrue();
@@ -170,6 +210,8 @@ public void testSetAndUseOptions() throws SQLException {
 .isEqualTo(MoreObjects.firstNonNull(System.getenv("SPANNER_OPTIMIZER_VERSION"), ""));
 assertThat(request.getQueryOptions().getOptimizerStatisticsPackage())
 .isEqualTo(MoreObjects.firstNonNull(System.getenv("OPTIMIZER_STATISTICS_PACKAGE"), ""));
+assertThat(request.getRequestOptions().getPriority().toString())
+.isEqualTo("PRIORITY_UNSPECIFIED");
 }
 }
 }
@@ -179,7 +221,7 @@ public void testUseOptionsFromConnectionUrl() throws SQLException {
 try (java.sql.Connection connection =
 DriverManager.getConnection(
 String.format(
-"jdbc:%s;optimizerVersion=10;optimizerStatisticsPackage=20210609_10_00_00",
+"jdbc:%s;optimizerVersion=10;optimizerStatisticsPackage=20210609_10_00_00;rpcPriority=LOW",
 getBaseUrl()))) {
 // Do a query and verify that the version from the connection URL is used.
 try (java.sql.ResultSet rs =
@@ -192,6 +234,7 @@ public void testUseOptionsFromConnectionUrl() throws SQLException {
 assertThat(request.getQueryOptions().getOptimizerVersion()).isEqualTo("10");
 assertThat(request.getQueryOptions().getOptimizerStatisticsPackage())
 .isEqualTo("20210609_10_00_00");
+assertThat(request.getRequestOptions().getPriority().toString()).isEqualTo("PRIORITY_LOW");
 }
 }
 }

@@ -107,7 +107,7 @@ public void testConnectWithURLWithDefaultValues() throws SQLException {
 @Test
 public void testConnectWithURLWithNonDefaultValues() throws SQLException {
 String url = createBaseUrl();
-url = url + ";autocommit=false;readonly=true;retryAbortsInternally=false";
+url = url + ";autocommit=false;readonly=true;retryAbortsInternally=false;rpcPriority=LOW";
 if (hasValidKeyFile()) {
 url = url + ";credentials=" + getKeyFile();
 }
@@ -138,6 +138,7 @@ public void testConnectWithPropertiesWithNonDefaultValues() throws SQLException
 properties.setProperty("autocommit", "false");
 properties.setProperty("readonly", "true");
 properties.setProperty("retryAbortsInternally", "false");
+properties.setProperty("rpcPriority", "LOW");
 try (Connection connection = DriverManager.getConnection(url, properties)) {
 testNonDefaultConnection(connection);
 }
@@ -146,14 +147,15 @@ public void testConnectWithPropertiesWithNonDefaultValues() throws SQLException
 @Test
 public void testConnectWithPropertiesWithConflictingValues() throws SQLException {
 String url = createBaseUrl();
-url = url + ";autocommit=false;readonly=true;retryAbortsInternally=false";
+url = url + ";autocommit=false;readonly=true;retryAbortsInternally=false;rpcPriority=LOW";
 if (hasValidKeyFile()) {
 url = url + ";credentials=" + getKeyFile();
 }
 Properties properties = new Properties();
 properties.setProperty("autocommit", "true");
 properties.setProperty("readonly", "false");
 properties.setProperty("retryAbortsInternally", "true");
+properties.setProperty("rpcPriority", "MEDIUM");
 try (Connection connection = DriverManager.getConnection(url, properties)) {
 testNonDefaultConnection(connection);
 }