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#!/usr/bin/env python
#
# Public Domain 2014-present MongoDB, Inc.
# Public Domain 2008-2014 WiredTiger, Inc.
#
# This is free and unencumbered software released into the public domain.
#
# Anyone is free to copy, modify, publish, use, compile, sell, or
# distribute this software, either in source code form or as a compiled
# binary, for any purpose, commercial or non-commercial, and by any
# means.
#
# In jurisdictions that recognize copyright laws, the author or authors
# of this software dedicate any and all copyright interest in the
# software to the public domain. We make this dedication for the benefit
# of the public at large and to the detriment of our heirs and
# successors. We intend this dedication to be an overt act of
# relinquishment in perpetuity of all present and future rights to this
# software under copyright law.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
# IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
# OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
# ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
# OTHER DEALINGS IN THE SOFTWARE.
import threading, time
import wttest
from wtthread import checkpoint_thread, named_checkpoint_thread
from helper import simulate_crash_restart
from wiredtiger import stat
from wtdataset import SimpleDataSet
from wtscenario import make_scenarios
# test_checkpoint14.py
#
# Make sure each checkpoint has its own snapshot by creating two successive
# inconsistent checkpoints and reading both of them.
class test_checkpoint(wttest.WiredTigerTestCase):
conn_config = 'statistics=(all),timing_stress_for_test=[checkpoint_slow]'
session_config = 'isolation=snapshot'
format_values = [
('column-fix', dict(key_format='r', value_format='8t',
extraconfig=',allocation_size=512,leaf_page_max=512')),
('column', dict(key_format='r', value_format='S', extraconfig='')),
('string_row', dict(key_format='S', value_format='S', extraconfig='')),
]
name_values = [
('nn', dict(first_checkpoint='first_checkpoint', second_checkpoint='second_checkpoint')),
('nu', dict(first_checkpoint='first_checkpoint', second_checkpoint=None)),
# This doesn't work because there's no way to open the first unnamed checkpoint.
#('un', dict(first_checkpoint=None, second_checkpoint='second_checkpoint')),
]
scenarios = make_scenarios(format_values, name_values)
def large_updates(self, uri, ds, nrows, value):
cursor = self.session.open_cursor(uri)
self.session.begin_transaction()
for i in range(1, nrows + 1):
cursor[ds.key(i)] = value
if i % 101 == 0:
self.session.commit_transaction()
self.session.begin_transaction()
self.session.commit_transaction()
cursor.close()
# "expected" is a list of maps from values to counts of values.
def check(self, ds, ckpt, nrows, value):
if ckpt is None:
ckpt = 'WiredTigerCheckpoint'
cursor = self.session.open_cursor(ds.uri, None, 'checkpoint=' + ckpt)
#self.session.begin_transaction()
count = 0
for k, v in cursor:
self.assertEqual(v, value)
count += 1
self.assertEqual(count, nrows)
#self.session.rollback_transaction()
cursor.close()
def test_checkpoint(self):
uri = 'table:checkpoint14'
nrows = 10000
# Create a table.
ds = SimpleDataSet(
self, uri, 0, key_format=self.key_format, value_format=self.value_format,
config=self.extraconfig)
ds.populate()
if self.value_format == '8t':
nrows *= 5
value_a = 97
value_b = 98
value_c = 99
else:
value_a = "aaaaa" * 100
value_b = "bbbbb" * 100
value_c = "ccccc" * 100
# Write some baseline data.
self.large_updates(uri, ds, nrows, value_a)
# Write this data out now so we aren't waiting for it while trying to
# race with the later data.
self.session.checkpoint()
# Write some more data, and hold the transaction open.
session2 = self.conn.open_session()
cursor2 = session2.open_cursor(uri)
session2.begin_transaction()
for i in range(1, nrows + 1):
cursor2[ds.key(i)] = value_b
# Checkpoint in the background.
done = threading.Event()
if self.first_checkpoint is None:
ckpt = checkpoint_thread(self.conn, done)
else:
ckpt = named_checkpoint_thread(self.conn, done, self.first_checkpoint)
try:
ckpt.start()
# Wait for checkpoint to start before committing.
ckpt_started = 0
while not ckpt_started:
stat_cursor = self.session.open_cursor('statistics:', None, None)
ckpt_started = stat_cursor[stat.conn.txn_checkpoint_running][2]
stat_cursor.close()
time.sleep(1)
session2.commit_transaction()
finally:
done.set()
ckpt.join()
# Rinse and repeat.
session2.begin_transaction()
for i in range(1, nrows + 1):
cursor2[ds.key(i)] = value_c
# Checkpoint in the background.
done = threading.Event()
if self.second_checkpoint is None:
ckpt = checkpoint_thread(self.conn, done)
else:
ckpt = named_checkpoint_thread(self.conn, done, self.second_checkpoint)
try:
ckpt.start()
# Sleep a bit so that checkpoint starts before committing last transaction.
time.sleep(2)
session2.commit_transaction()
finally:
done.set()
ckpt.join()
# Other tests check for whether the visibility of a partially-written transaction
# is handled correctly. Here we're interested in whether the visibility mechanism
# is using the right snapshot for the checkpoint we're reading. So insist that we
# not see the value_b transaction in the first checkpoint, or the value_c transaction
# in the second checkpoint. If test machine lag causes either transaction to commit
# before the checkpoint starts, we'll see value_b in the first checkpoint and/or
# value_c in the second. But also, if we end up using the second checkpoint's snapshot
# for the first checkpoint, we'll see value_b. So if this happens more than once in a
# blue moon we should probably strengthen the test so we can more reliably distinguish
# the cases, probably by doing a third transaction/checkpoint pair.
#
# If we end up using the first checkpoint's snapshot for reading the second checkpoint,
# we'll most likely see no data at all; that would be a serious failure if it happened.
# Read the checkpoints.
self.check(ds, self.first_checkpoint, nrows, value_a)
self.check(ds, self.second_checkpoint, nrows, value_b)
# If we haven't died yet, pretend to crash, and run RTS to see if the
# (second) checkpoint was inconsistent. Unfortunately we can't readily
# check on both.
simulate_crash_restart(self, ".", "RESTART")
# Make sure we did get an inconsistent checkpoint.
stat_cursor = self.session.open_cursor('statistics:', None, None)
inconsistent_ckpt = stat_cursor[stat.conn.txn_rts_inconsistent_ckpt][2]
stat_cursor.close()
self.assertGreater(inconsistent_ckpt, 0)
if __name__ == '__main__':
wttest.run()
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