Fix to not drop the metadata table when renaming table

core/src/integration-test/java/com/scalar/db/storage/cassandra/CassandraAdminCaseSensitivityIntegrationTest.java

@@ -105,4 +105,8 @@ public void renameTable_IfNewTableNameAlreadyExists_ShouldThrowIllegalArgumentEx
   @Override
   @Disabled("Cassandra does not support renaming tables")
   public void renameTable_ForExistingTableWithIndexes_ShouldRenameTableAndIndexesCorrectly() {}
+
+  @Override
+  @Disabled("Cassandra does not support renaming tables")
+  public void renameTable_IfOnlyOneTableExists_ShouldRenameTableCorrectly() {}
 }

core/src/integration-test/java/com/scalar/db/storage/cassandra/CassandraAdminIntegrationTest.java

@@ -104,4 +104,8 @@ public void renameTable_IfNewTableNameAlreadyExists_ShouldThrowIllegalArgumentEx
   @Override
   @Disabled("Cassandra does not support renaming tables")
   public void renameTable_ForExistingTableWithIndexes_ShouldRenameTableAndIndexesCorrectly() {}
+
+  @Override
+  @Disabled("Cassandra does not support renaming tables")
+  public void renameTable_IfOnlyOneTableExists_ShouldRenameTableCorrectly() {}
 }

core/src/integration-test/java/com/scalar/db/storage/cassandra/ConsensusCommitAdminIntegrationTestWithCassandra.java

@@ -104,4 +104,8 @@ public void renameTable_IfNewTableNameAlreadyExists_ShouldThrowIllegalArgumentEx
   @Override
   @Disabled("Cassandra does not support renaming tables")
   public void renameTable_ForExistingTableWithIndexes_ShouldRenameTableAndIndexesCorrectly() {}
+
+  @Override
+  @Disabled("Cassandra does not support renaming tables")
+  public void renameTable_IfOnlyOneTableExists_ShouldRenameTableCorrectly() {}
 }

core/src/integration-test/java/com/scalar/db/storage/cassandra/SingleCrudOperationTransactionAdminIntegrationTestWithCassandra.java

@@ -99,4 +99,8 @@ public void renameTable_IfNewTableNameAlreadyExists_ShouldThrowIllegalArgumentEx
   @Override
   @Disabled("Cassandra does not support renaming tables")
   public void renameTable_ForExistingTableWithIndexes_ShouldRenameTableAndIndexesCorrectly() {}
+
+  @Override
+  @Disabled("Cassandra does not support renaming tables")
+  public void renameTable_IfOnlyOneTableExists_ShouldRenameTableCorrectly() {}
 }

core/src/integration-test/java/com/scalar/db/storage/cosmos/ConsensusCommitAdminIntegrationTestWithCosmos.java

@@ -96,4 +96,8 @@ public void renameTable_IfNewTableNameAlreadyExists_ShouldThrowIllegalArgumentEx
   @Override
   @Disabled("Cosmos DB does not support renaming tables")
   public void renameTable_ForExistingTableWithIndexes_ShouldRenameTableAndIndexesCorrectly() {}
+
+  @Override
+  @Disabled("Cosmos DB does not support renaming tables")
+  public void renameTable_IfOnlyOneTableExists_ShouldRenameTableCorrectly() {}
 }

core/src/integration-test/java/com/scalar/db/storage/cosmos/CosmosAdminCaseSensitivityIntegrationTest.java

@@ -96,4 +96,8 @@ public void renameTable_IfNewTableNameAlreadyExists_ShouldThrowIllegalArgumentEx
   @Override
   @Disabled("Cosmos DB does not support renaming tables")
   public void renameTable_ForExistingTableWithIndexes_ShouldRenameTableAndIndexesCorrectly() {}
+
+  @Override
+  @Disabled("Cosmos DB does not support renaming tables")
+  public void renameTable_IfOnlyOneTableExists_ShouldRenameTableCorrectly() {}
 }

core/src/integration-test/java/com/scalar/db/storage/cosmos/CosmosAdminIntegrationTest.java

@@ -95,4 +95,8 @@ public void renameTable_IfNewTableNameAlreadyExists_ShouldThrowIllegalArgumentEx
   @Override
   @Disabled("Cosmos DB does not support renaming tables")
   public void renameTable_ForExistingTableWithIndexes_ShouldRenameTableAndIndexesCorrectly() {}
+
+  @Override
+  @Disabled("Cosmos DB does not support renaming tables")
+  public void renameTable_IfOnlyOneTableExists_ShouldRenameTableCorrectly() {}
 }

core/src/integration-test/java/com/scalar/db/storage/cosmos/SingleCrudOperationTransactionAdminIntegrationTestWithCosmos.java

@@ -90,4 +90,8 @@ public void renameTable_IfNewTableNameAlreadyExists_ShouldThrowIllegalArgumentEx
   @Override
   @Disabled("Cosmos DB does not support renaming tables")
   public void renameTable_ForExistingTableWithIndexes_ShouldRenameTableAndIndexesCorrectly() {}
+
+  @Override
+  @Disabled("Cosmos DB does not support renaming tables")
+  public void renameTable_IfOnlyOneTableExists_ShouldRenameTableCorrectly() {}
 }

core/src/integration-test/java/com/scalar/db/storage/dynamo/ConsensusCommitAdminIntegrationTestWithDynamo.java

@@ -101,4 +101,8 @@ public void renameTable_IfNewTableNameAlreadyExists_ShouldThrowIllegalArgumentEx
   @Override
   @Disabled("DynamoDB does not support renaming tables")
   public void renameTable_ForExistingTableWithIndexes_ShouldRenameTableAndIndexesCorrectly() {}
+
+  @Override
+  @Disabled("DynamoDB does not support renaming tables")
+  public void renameTable_IfOnlyOneTableExists_ShouldRenameTableCorrectly() {}
 }

core/src/integration-test/java/com/scalar/db/storage/dynamo/DynamoAdminCaseSensitivityIntegrationTest.java

@@ -101,4 +101,8 @@ public void renameTable_IfNewTableNameAlreadyExists_ShouldThrowIllegalArgumentEx
   @Override
   @Disabled("DynamoDB does not support renaming tables")
   public void renameTable_ForExistingTableWithIndexes_ShouldRenameTableAndIndexesCorrectly() {}
+
+  @Override
+  @Disabled("DynamoDB does not support renaming tables")
+  public void renameTable_IfOnlyOneTableExists_ShouldRenameTableCorrectly() {}
 }

core/src/integration-test/java/com/scalar/db/storage/dynamo/DynamoAdminIntegrationTest.java

@@ -100,4 +100,8 @@ public void renameTable_IfNewTableNameAlreadyExists_ShouldThrowIllegalArgumentEx
   @Override
   @Disabled("DynamoDB does not support renaming tables")
   public void renameTable_ForExistingTableWithIndexes_ShouldRenameTableAndIndexesCorrectly() {}
+
+  @Override
+  @Disabled("DynamoDB does not support renaming tables")
+  public void renameTable_IfOnlyOneTableExists_ShouldRenameTableCorrectly() {}
 }

core/src/integration-test/java/com/scalar/db/storage/dynamo/SingleCrudOperationTransactionAdminIntegrationTestWithDynamo.java

@@ -95,4 +95,8 @@ public void renameTable_IfNewTableNameAlreadyExists_ShouldThrowIllegalArgumentEx
   @Override
   @Disabled("DynamoDB does not support renaming tables")
   public void renameTable_ForExistingTableWithIndexes_ShouldRenameTableAndIndexesCorrectly() {}
+
+  @Override
+  @Disabled("DynamoDB does not support renaming tables")
+  public void renameTable_IfOnlyOneTableExists_ShouldRenameTableCorrectly() {}
 }

core/src/main/java/com/scalar/db/storage/jdbc/JdbcAdmin.java

@@ -409,7 +409,7 @@ private String computeBooleanValue(boolean value) {
   public void dropTable(String namespace, String table) throws ExecutionException {
     try (Connection connection = dataSource.getConnection()) {
       dropTableInternal(connection, namespace, table);
-      deleteTableMetadata(connection, namespace, table);
+      deleteTableMetadata(connection, namespace, table, true);
       deleteNamespacesTableAndMetadataSchemaIfEmpty(connection);
     } catch (SQLException e) {
       throw new ExecutionException(
@@ -423,11 +423,14 @@ private void dropTableInternal(Connection connection, String schema, String tabl
     execute(connection, dropTableStatement);
   }
 
-  private void deleteTableMetadata(Connection connection, String namespace, String table)
+  private void deleteTableMetadata(
+      Connection connection, String namespace, String table, boolean deleteMetadataTableIfEmpty)
       throws SQLException {
     try {
       execute(connection, getDeleteTableMetadataStatement(namespace, table));
-      deleteMetadataTableIfEmpty(connection);
+      if (deleteMetadataTableIfEmpty) {
+        deleteMetadataTableIfEmpty(connection);
+      }
     } catch (SQLException e) {
       if (e.getMessage().contains("Unknown table") || e.getMessage().contains("does not exist")) {
         return;
@@ -1015,7 +1018,7 @@ public void renameTable(String namespace, String oldTableName, String newTableNa
       String renameTableStatement = rdbEngine.renameTableSql(namespace, oldTableName, newTableName);
       try (Connection connection = dataSource.getConnection()) {
         execute(connection, renameTableStatement);
-        deleteTableMetadata(connection, namespace, oldTableName);
+        deleteTableMetadata(connection, namespace, oldTableName, false);
         for (String indexedColumnName : tableMetadata.getSecondaryIndexNames()) {
           String oldIndexName = getIndexName(namespace, oldTableName, indexedColumnName);
           String newIndexName = getIndexName(namespace, newTableName, indexedColumnName);

core/src/test/java/com/scalar/db/storage/jdbc/JdbcAdminTest.java

@@ -3425,7 +3425,6 @@ public void renameTable_ForMysql_ShouldWorkProperly() throws SQLException, Execu
             + "`.`metadata` WHERE `full_table_name`=? ORDER BY `ordinal_position` ASC",
         "ALTER TABLE `ns`.`table` RENAME TO `ns`.`table_new`",
         "DELETE FROM `" + METADATA_SCHEMA + "`.`metadata` WHERE `full_table_name` = 'ns.table'",
-        "SELECT DISTINCT `full_table_name` FROM `" + METADATA_SCHEMA + "`.`metadata`",
         "INSERT INTO `"
             + METADATA_SCHEMA
             + "`.`metadata` VALUES ('ns.table_new','c1','TEXT','PARTITION',NULL,false,1)",
@@ -3445,7 +3444,6 @@ public void renameTable_ForOracle_ShouldWorkProperly() throws SQLException, Exec
         "DELETE FROM \""
             + METADATA_SCHEMA
             + "\".\"metadata\" WHERE \"full_table_name\" = 'ns.table'",
-        "SELECT DISTINCT \"full_table_name\" FROM \"" + METADATA_SCHEMA + "\".\"metadata\"",
         "INSERT INTO \""
             + METADATA_SCHEMA
             + "\".\"metadata\" VALUES ('ns.table_new','c1','TEXT','PARTITION',NULL,0,1)",
@@ -3466,7 +3464,6 @@ public void renameTable_ForPostgresql_ShouldWorkProperly()
         "DELETE FROM \""
             + METADATA_SCHEMA
             + "\".\"metadata\" WHERE \"full_table_name\" = 'ns.table'",
-        "SELECT DISTINCT \"full_table_name\" FROM \"" + METADATA_SCHEMA + "\".\"metadata\"",
         "INSERT INTO \""
             + METADATA_SCHEMA
             + "\".\"metadata\" VALUES ('ns.table_new','c1','TEXT','PARTITION',NULL,false,1)",
@@ -3485,7 +3482,6 @@ public void renameTable_ForSqlServer_ShouldWorkProperly()
             + "].[metadata] WHERE [full_table_name]=? ORDER BY [ordinal_position] ASC",
         "EXEC sp_rename '[ns].[table]', 'table_new'",
         "DELETE FROM [" + METADATA_SCHEMA + "].[metadata] WHERE [full_table_name] = 'ns.table'",
-        "SELECT DISTINCT [full_table_name] FROM [" + METADATA_SCHEMA + "].[metadata]",
         "INSERT INTO ["
             + METADATA_SCHEMA
             + "].[metadata] VALUES ('ns.table_new','c1','TEXT','PARTITION',NULL,0,1)",
@@ -3503,7 +3499,6 @@ public void renameTable_ForSqlite_ShouldWorkProperly() throws SQLException, Exec
             + "$metadata\" WHERE \"full_table_name\"=? ORDER BY \"ordinal_position\" ASC",
         "ALTER TABLE \"ns$table\" RENAME TO \"ns$table_new\"",
         "DELETE FROM \"" + METADATA_SCHEMA + "$metadata\" WHERE \"full_table_name\" = 'ns.table'",
-        "SELECT DISTINCT \"full_table_name\" FROM \"" + METADATA_SCHEMA + "$metadata\"",
         "INSERT INTO \""
             + METADATA_SCHEMA
             + "$metadata\" VALUES ('ns.table_new','c1','TEXT','PARTITION',NULL,FALSE,1)",
@@ -3523,7 +3518,6 @@ public void renameTable_ForDb2_ShouldWorkProperly() throws SQLException, Executi
         "DELETE FROM \""
             + METADATA_SCHEMA
             + "\".\"metadata\" WHERE \"full_table_name\" = 'ns.table'",
-        "SELECT DISTINCT \"full_table_name\" FROM \"" + METADATA_SCHEMA + "\".\"metadata\"",
         "INSERT INTO \""
             + METADATA_SCHEMA
             + "\".\"metadata\" VALUES ('ns.table_new','c1','TEXT','PARTITION',NULL,false,1)",

integration-test/src/main/java/com/scalar/db/api/DistributedStorageAdminIntegrationTestBase.java

@@ -1568,6 +1568,36 @@ public void renameTable_ForExistingTableWithIndexes_ShouldRenameTableAndIndexesC
     }
   }
 
+  @Test
+  public void renameTable_IfOnlyOneTableExists_ShouldRenameTableCorrectly()
+      throws ExecutionException {
+    String newTableName = "new" + getTable4();
+    try {
+      // Arrange
+      admin.createNamespace(namespace3);
+      Map<String, String> options = getCreationOptions();
+      TableMetadata tableMetadata =
+          TableMetadata.newBuilder()
+              .addColumn(getColumnName1(), DataType.INT)
+              .addColumn(getColumnName2(), DataType.INT)
+              .addPartitionKey(getColumnName1())
+              .build();
+      admin.createTable(namespace3, getTable4(), tableMetadata, options);
+
+      // Act
+      admin.renameTable(namespace3, getTable4(), newTableName);
+
+      // Assert
+      assertThat(admin.tableExists(namespace3, getTable4())).isFalse();
+      assertThat(admin.tableExists(namespace3, newTableName)).isTrue();
+      assertThat(admin.getTableMetadata(namespace3, newTableName)).isEqualTo(tableMetadata);
+    } finally {
+      admin.dropTable(namespace3, getTable4(), true);
+      admin.dropTable(namespace3, newTableName, true);
+      admin.dropNamespace(namespace3, true);
+    }
+  }
+
   @Test
   public void alterColumnType_ForNonExistingTable_ShouldThrowIllegalArgumentException() {
     // Arrange

integration-test/src/main/java/com/scalar/db/api/DistributedTransactionAdminIntegrationTestBase.java

@@ -1464,6 +1464,36 @@ public void renameTable_ForExistingTableWithIndexes_ShouldRenameTableAndIndexesC
     }
   }
 
+  @Test
+  public void renameTable_IfOnlyOneTableExists_ShouldRenameTableCorrectly()
+      throws ExecutionException {
+    String newTableName = "new" + TABLE4;
+    try {
+      // Arrange
+      admin.createNamespace(namespace3);
+      Map<String, String> options = getCreationOptions();
+      TableMetadata tableMetadata =
+          TableMetadata.newBuilder()
+              .addColumn("c1", DataType.INT)
+              .addColumn("c2", DataType.INT)
+              .addPartitionKey("c1")
+              .build();
+      admin.createTable(namespace3, TABLE4, tableMetadata, options);
+
+      // Act
+      admin.renameTable(namespace3, TABLE4, newTableName);
+
+      // Assert
+      assertThat(admin.tableExists(namespace3, TABLE4)).isFalse();
+      assertThat(admin.tableExists(namespace3, newTableName)).isTrue();
+      assertThat(admin.getTableMetadata(namespace3, newTableName)).isEqualTo(tableMetadata);
+    } finally {
+      admin.dropTable(namespace3, TABLE4, true);
+      admin.dropTable(namespace3, newTableName, true);
+      admin.dropNamespace(namespace3, true);
+    }
+  }
+
   @Test
   public void createCoordinatorTables_ShouldCreateCoordinatorTablesCorrectly()
       throws ExecutionException {