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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 wttest
from wiredtiger import stat, WiredTigerError, wiredtiger_strerror, WT_ROLLBACK
from wtdataset import SimpleDataSet
from wtscenario import make_scenarios
# test_truncate17.py
#
# Make sure that no shenanigans occur if we try to read from a page that's been
# fast-truncated by a prepared transaction.
class test_truncate17(wttest.WiredTigerTestCase):
conn_config = 'statistics=(all)'
session_config = 'isolation=snapshot'
# Hook to run using remove instead of truncate for reference. This should not alter the
# behavior... but may if things are broken. Disable the reference version by default as it's
# only useful when investigating behavior changes. This list is first in the make_scenarios
# call so the additional cases don't change the scenario numbering.
trunc_values = [
('truncate', dict(trunc_with_remove=False)),
#('remove', dict(trunc_with_remove=True)),
]
format_values = [
('column', dict(key_format='r', value_format='S', extraconfig='')),
('column_fix', dict(key_format='r', value_format='8t',
extraconfig=',allocation_size=512,leaf_page_max=512')),
('integer_row', dict(key_format='i', value_format='S', extraconfig='')),
]
checkpoint_values = [
('no_checkpoint', dict(do_checkpoint=False)),
('checkpoint', dict(do_checkpoint=True)),
]
scenarios = make_scenarios(trunc_values, format_values, checkpoint_values)
def stat_tree(self, uri):
statscursor = self.session.open_cursor('statistics:' + uri, None, 'statistics=(all)')
entries = statscursor[stat.dsrc.btree_entries][2]
if self.value_format == '8t':
leaf_pages = statscursor[stat.dsrc.btree_column_fix][2]
internal_pages = statscursor[stat.dsrc.btree_column_internal][2]
elif self.key_format == 'r':
leaf_pages = statscursor[stat.dsrc.btree_column_variable][2]
internal_pages = statscursor[stat.dsrc.btree_column_internal][2]
else:
leaf_pages = statscursor[stat.dsrc.btree_row_leaf][2]
internal_pages = statscursor[stat.dsrc.btree_row_internal][2]
return (entries, (leaf_pages, internal_pages))
def truncate(self, session, uri, make_key, keynum1, keynum2):
if self.trunc_with_remove:
cursor = session.open_cursor(uri)
err = 0
for k in range(keynum1, keynum2 + 1):
cursor.set_key(k)
try:
err = cursor.remove()
except WiredTigerError as e:
if wiredtiger_strerror(WT_ROLLBACK) in str(e):
err = WT_ROLLBACK
else:
raise e
if err != 0:
break
cursor.close()
else:
lo_cursor = session.open_cursor(uri)
hi_cursor = session.open_cursor(uri)
lo_cursor.set_key(make_key(keynum1))
hi_cursor.set_key(make_key(keynum2))
try:
err = session.truncate(None, lo_cursor, hi_cursor, None)
except WiredTigerError as e:
if wiredtiger_strerror(WT_ROLLBACK) in str(e):
err = WT_ROLLBACK
else:
raise e
lo_cursor.close()
hi_cursor.close()
return err
def test_truncate17(self):
nrows = 10000
# Create a table.
uri = "table:truncate17"
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':
value_a = 97
value_b = 98
else:
value_a = "aaaaa" * 100
value_b = "bbbbb" * 100
# Pin oldest and stable timestamps to 1.
self.conn.set_timestamp('oldest_timestamp=' + self.timestamp_str(1) +
',stable_timestamp=' + self.timestamp_str(1))
# Write some baseline data at time 10.
cursor = self.session.open_cursor(ds.uri)
self.session.begin_transaction()
for i in range(1, nrows + 1):
cursor[ds.key(i)] = value_a
if i % 487 == 0:
self.session.commit_transaction('commit_timestamp=' + self.timestamp_str(10))
self.session.begin_transaction()
self.session.commit_transaction('commit_timestamp=' + self.timestamp_str(10))
cursor.close()
# Mark it stable.
self.conn.set_timestamp('stable_timestamp=' + self.timestamp_str(10))
# Reopen the connection so as to stat the on-disk version of the tree.
self.reopen_conn()
# Stat the tree to get a baseline.
(base_entries, base_pages) = self.stat_tree(uri)
self.assertEqual(base_entries, nrows)
# Reopen the connection again so nothing is in memory and we can fast-truncate.
self.reopen_conn()
# Make a session to prepare in.
session2 = self.conn.open_session()
# Truncate the middle of the table.
#
# Prepare the truncate at time 20 and leave it hanging.
session2.begin_transaction()
err = self.truncate(session2, ds.uri, ds.key, nrows // 4 + 1, 3 * nrows // 4)
self.assertEqual(err, 0)
session2.prepare_transaction('prepare_timestamp=' + self.timestamp_str(20))
# Make sure we did at least one fast-delete. (Unless we specifically didn't want to,
# or running on FLCS where it isn't supported.)
stat_cursor = self.session.open_cursor('statistics:', None, None)
fastdelete_pages = stat_cursor[stat.conn.rec_page_delete_fast][2]
if self.value_format == '8t' or self.trunc_with_remove:
self.assertEqual(fastdelete_pages, 0)
else:
self.assertGreater(fastdelete_pages, 0)
stat_cursor.close()
# Optionally checkpoint at this stage, just in case it breaks or trips on
# the prepared truncation.
if self.do_checkpoint:
self.session.checkpoint()
# Stat the tree again. Stats are not transactional, and are effectively
# read-uncommitted; we should see the results of the prepared truncate.
# However, the truncated pages aren't actually gone yet, so the page counts
# shouldn't change.
(entries, pages) = self.stat_tree(uri)
if self.value_format == '8t':
self.assertEqual(entries, nrows)
else:
self.assertEqual(entries, nrows // 2)
self.assertEqual(pages, base_pages)
# This should instantiate all the deleted pages.
stat_cursor = self.session.open_cursor('statistics:', None, None)
read_deleted = stat_cursor[stat.conn.cache_read_deleted][2]
self.assertEqual(read_deleted, fastdelete_pages)
stat_cursor.close()
# Now toss the prepared transaction.
session2.rollback_transaction()
# Unlike RTS, transaction rollback should not instantiate pages, plus there are
# no more deleted pages to instantiate, so the number of instantiated pages should
# remain unchanged.
stat_cursor = self.session.open_cursor('statistics:', None, None)
read_deleted = stat_cursor[stat.conn.cache_read_deleted][2]
self.assertEqual(read_deleted, fastdelete_pages)
stat_cursor.close()
if __name__ == '__main__':
wttest.run()
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