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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 wtdataset import SimpleDataSet
from wtscenario import make_scenarios
# test_prepare_hs01.py
# test to ensure history store eviction is working for prepared transactions.
class test_prepare_hs01(wttest.WiredTigerTestCase):
# Force a small cache.
conn_config = 'cache_size=50MB,eviction_updates_trigger=95,eviction_updates_target=80'
format_values = [
('column', dict(key_format='r', value_format='u')),
('column-fix', dict(key_format='r', value_format='8t')),
('string-row', dict(key_format='S', value_format='u')),
]
scenarios = make_scenarios(format_values)
def check(self, uri, ds, nrows, nsessions, nkeys, read_ts, expected_value, not_expected_value):
cursor = self.session.open_cursor(uri)
self.session.begin_transaction('read_timestamp=' + self.timestamp_str(read_ts))
for i in range(1, nsessions * nkeys):
cursor.set_key(ds.key(nrows + i))
self.assertEquals(cursor.search(), 0)
# Correctness Test - commit_value should be visible
self.assertEquals(cursor.get_value(), expected_value)
# Correctness Test - prepare_value should NOT be visible
self.assertNotEquals(cursor.get_value(), not_expected_value)
cursor.close()
self.session.commit_transaction()
def prepare_updates(self, uri, ds, nrows, nsessions, nkeys):
# Update a large number of records in their individual transactions.
# This will force eviction and start history store eviction of committed
# updates.
#
# Follow this by updating a number of records in prepared transactions
# under multiple sessions. We'll hang if the history store table isn't doing its
# thing. If we do all updates in a single session, then hang will be due
# to uncommitted updates, instead of prepared updates.
#
# Do another set of updates in that many transactions. This forces the
# pages that have been evicted to the history store to be re-read and brought in
# memory. Hence testing if we can read prepared updates from the history store.
# Start with setting a stable timestamp to pin history in cache
self.conn.set_timestamp('stable_timestamp=' + self.timestamp_str(1))
if self.value_format == '8t':
bigvalue1 = 98
bigvalue2 = 99
else:
bigvalue1 = b"bbbbb" * 100
bigvalue2 = b"ccccc" * 100
# Commit some updates to get eviction and history store fired up
cursor = self.session.open_cursor(uri)
for i in range(1, nsessions * nkeys):
self.session.begin_transaction()
cursor.set_key(ds.key(nrows + i))
cursor.set_value(bigvalue1)
self.assertEquals(cursor.insert(), 0)
self.session.commit_transaction('commit_timestamp=' + self.timestamp_str(2))
# Have prepared updates in multiple sessions. This should ensure writing
# prepared updates to the history store
sessions = [0] * nsessions
cursors = [0] * nsessions
for j in range (0, nsessions):
sessions[j] = self.conn.open_session()
sessions[j].begin_transaction()
cursors[j] = sessions[j].open_cursor(uri)
# Each session will update many consecutive keys.
start = (j * nkeys)
end = start + nkeys
for i in range(start, end):
cursors[j].set_key(ds.key(nrows + i))
cursors[j].set_value(bigvalue2)
self.assertEquals(cursors[j].insert(), 0)
sessions[j].prepare_transaction('prepare_timestamp=' + self.timestamp_str(3))
# Re-read the original versions of all the data. This ensures reading
# original versions from the history store
self.check(uri, ds, nrows, nsessions, nkeys, 2, bigvalue1, bigvalue2)
# Close all cursors and sessions, this will cause prepared updates to be
# rollback-ed
for j in range (0, nsessions):
cursors[j].close()
sessions[j].close()
# Re-read the original versions of all the data. This ensures reading
# original versions from the data store as the prepared updates are
# aborted
self.check(uri, ds, nrows, nsessions, nkeys, 3, bigvalue1, bigvalue2)
def test_prepare_hs(self):
# Create a small table.
uri = "table:test_prepare_hs01"
nrows = 100
ds = SimpleDataSet(
self, uri, nrows, key_format=self.key_format, value_format=self.value_format)
ds.populate()
if self.value_format == '8t':
bigvalue = 97
else:
bigvalue = b"aaaaa" * 100
# Initially load huge data
cursor = self.session.open_cursor(uri)
for i in range(1, 10000):
cursor.set_key(ds.key(nrows + i))
cursor.set_value(bigvalue)
self.assertEquals(cursor.insert(), 0)
cursor.close()
self.session.checkpoint()
# Check if the history store is working properly with prepare transactions.
# We put prepared updates in multiple sessions so that we do not hang
# because of cache being full with uncommitted updates.
nsessions = 3
nkeys = 4000
self.prepare_updates(uri, ds, nrows, nsessions, nkeys)
if __name__ == '__main__':
wttest.run()
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