public static Schema getTableSchema(TableId tableId) {
        ValuesTable table = globalTables.get(tableId);
        Preconditions.checkNotNull(table, tableId + " is not existed");
        Schema.Builder builder = Schema.newBuilder();
        for (Column column : table.columns) {
            builder.physicalColumn(column.getName(), column.getType());
        }
        return builder.primaryKey(table.primaryKeys).build();
    }
@Test
    public void testValuesMetadataAccessor() {
        Schema schema =
                Schema.newBuilder()
                        .physicalColumn("col1", new CharType())
                        .physicalColumn("col2", new CharType())
                        .primaryKey("col1")
                        .build();
        Assert.assertEquals(2, metadataAccessor.listNamespaces().size());
        Assert.assertEquals(2, metadataAccessor.listSchemas(null).size());
        Assert.assertEquals(1, metadataAccessor.listTables(null, "default").size());
        Assert.assertEquals(schema, metadataAccessor.getTableSchema(table1));
    }