Files
impala/tests/query_test/test_limit.py
2014-01-08 10:48:48 -08:00

105 lines
4.4 KiB
Python

#!/usr/bin/env python
# Copyright (c) 2012 Cloudera, Inc. All rights reserved.
# Validates limit on scan nodes
#
import logging
import pytest
from copy import copy
from tests.beeswax.impala_beeswax import ImpalaBeeswaxException
from tests.common.impala_test_suite import ImpalaTestSuite
from tests.common.test_vector import *
from tests.util.test_file_parser import QueryTestSectionReader
class TestLimit(ImpalaTestSuite):
LIMIT_VALUES = [1, 2, 3, 4, 5, 10, 100, 5000]
QUERIES = ["select * from lineitem limit %d"]
# TODO: we should be able to run count(*) in setup rather than hardcoding the values
# but I have no idea how to do this with this framework.
TOTAL_ROWS = 6001215
@classmethod
def get_workload(self):
return 'tpch'
@classmethod
def add_test_dimensions(cls):
super(TestLimit, cls).add_test_dimensions()
# Add two more dimensions
cls.TestMatrix.add_dimension(
TestDimension('limit_value', *TestLimit.LIMIT_VALUES))
cls.TestMatrix.add_dimension(TestDimension('query', *TestLimit.QUERIES))
# Don't run with large limits and tiny batch sizes. This generates excessive
# network traffic and makes the machine run very slowly.
cls.TestMatrix.add_constraint(lambda v:\
v.get_value('limit_value') < 100 or v.get_value('exec_option')['batch_size'] == 0)
cls.TestMatrix.add_constraint(lambda v:\
v.get_value('table_format').file_format != 'parquet')
def test_limit(self, vector):
# We can't validate the rows that are returned since that is non-deterministic.
# This is why this is a python test rather than a .test.
limit = vector.get_value('limit_value')
expected_num_rows = min(limit, TestLimit.TOTAL_ROWS)
query_string = vector.get_value('query') % limit
result = self.execute_query(query_string, vector.get_value('exec_option'),
table_format=vector.get_value('table_format'))
assert(len(result.data) == expected_num_rows)
# Validates the default order by limit query option functionality
class TestDefaultOrderByLimitValue(ImpalaTestSuite):
# Interesting default limit values. TODO: What about value of -2?
DEFAULT_ORDER_BY_LIMIT_VALUES = [None, -1, 0, 1, 10, 100]
@classmethod
def get_workload(self):
return 'functional-query'
@classmethod
def add_test_dimensions(cls):
super(TestDefaultOrderByLimitValue, cls).add_test_dimensions()
# Not interested in exploring different file formats
cls.TestMatrix.clear_dimension('table_format')
cls.TestMatrix.add_dimension(TestDimension('default_order_by_limit_value',
*TestDefaultOrderByLimitValue.DEFAULT_ORDER_BY_LIMIT_VALUES))
cls.TestMatrix.add_constraint(lambda v:\
v.get_value('exec_option')['batch_size'] == 0)
def test_default_order_by_limit_values(self, vector):
limit_value = vector.get_value('default_order_by_limit_value')
exec_options = copy(vector.get_value('exec_option'))
if limit_value is not None:
exec_options['default_order_by_limit'] = limit_value
# Unless the default order by limit is -1 or None (not specified) we expect SELECT
# ORDER BY without any limit specified to work properly.
no_limit_should_succeed = limit_value not in [None, -1]
# Validate the default order by limit option kicks on when no limit is specified.
query_no_limit = "select * from functional.alltypes order by int_col"
self.exec_query_validate(query_no_limit, exec_options,
no_limit_should_succeed, limit_value)
# Validate that user specified limits override the default limit value.
query_with_limit = "select * from functional.alltypes order by int_col limit 20"
self.exec_query_validate(query_with_limit, exec_options, True, 20)
query_no_orderby = "select * from functional.alltypes limit 25"
self.exec_query_validate(query_no_orderby, exec_options, True, 25)
def exec_query_validate(self, query, exec_options, should_succeed, expected_rows):
"""Executes a query and validates the results"""
try:
result = self.execute_query(query, exec_options)
assert should_succeed, 'Query was expected to fail'
assert len(result.data) == expected_rows,\
'Wrong number of rows returned %d' % len(result.data)
except ImpalaBeeswaxException as e:
assert not should_succeed, 'Query was not expected to fail: %s' % e
assert 'ORDER BY without LIMIT currently not supported' in str(e)