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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 re
from wiredtiger import stat
from wtdataset import SimpleDataSet
from wtscenario import make_scenarios
from helper import simulate_crash_restart
from test_rollback_to_stable01 import test_rollback_to_stable_base
# test_rollback_to_stable28.py
# Test the debug mode setting for update_restore_evict during recovery.
# Force update restore eviction, whenever we evict a page. We want to
# perform this in recovery to ensure that all the in-memory images have
# the proper write generation number and we don't end up reading stale
# transaction ID's stored on the page.
class test_rollback_to_stable28(test_rollback_to_stable_base):
conn_config = 'log=(enabled=true),statistics=(all)'
# Recovery connection config: The debug mode is only effective on high cache pressure as WiredTiger can potentially decide
# to do an update restore evict on a page when the cache pressure requirements are not met.
# This means setting eviction target low and cache size low.
conn_recon = ',eviction_updates_trigger=10,eviction_dirty_trigger=5,eviction_dirty_target=1,' \
'cache_size=1MB,debug_mode=(update_restore_evict=true),log=(recover=on)'
# In principle this test should be run on VLCS and FLCS; but it doesn't run reliably, in that
# while it always works in the sense of producing the right values, it doesn't always trigger
# update restore eviction, and then the assertions about that fail. For FLCS, using small
# pages and twice as many rows makes it work most of the time, but not always (especially on
# the test machines...) and it also apparently fails some of the time on VLCS. For the moment
# we've concluded that the marginal benefit of running on VLCS and particularly FLCS is small
# so disabling these scenarios seems like the best strategy.
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')),
('row_integer', dict(key_format='i', value_format='S', extraconfig='')),
]
scenarios = make_scenarios(format_values)
def parse_write_gen(self, uri):
meta_cursor = self.session.open_cursor('metadata:')
config = meta_cursor[uri]
meta_cursor.close()
# The search string will look like: 'run_write_gen=<num>'.
# Just reverse the string and take the digits from the back until we hit '='.
write_gen = re.search('write_gen=\d+', config)
run_write_gen = re.search('run_write_gen=\d+', config)
self.assertTrue(write_gen is not None)
write_gen_str = str()
run_write_gen_str = str()
for c in reversed(write_gen.group(0)):
if not c.isdigit():
self.assertEqual(c, '=')
break
write_gen_str = c + write_gen_str
for c in reversed(run_write_gen.group(0)):
if not c.isdigit():
self.assertEqual(c, '=')
break
run_write_gen_str = c + run_write_gen_str
return int(write_gen_str), int(run_write_gen_str)
def test_update_restore_evict_recovery(self):
uri = 'table:test_debug_mode10'
nrows = 10000
# Create our table.
ds = SimpleDataSet(self, uri, 0, key_format=self.key_format, value_format=self.value_format,
config='log=(enabled=false)' + self.extraconfig)
ds.populate()
if self.value_format == '8t':
nrows *= 2
value_a = 97
value_b = 98
value_c = 99
value_d = 100
else:
value_a = 'a' * 500
value_b = 'b' * 500
value_c = 'c' * 500
value_d = 'd' * 500
# Perform several updates.
self.large_updates(uri, value_a, ds, nrows, False, 20)
self.large_updates(uri, value_b, ds, nrows, False, 30)
self.large_updates(uri, value_c, ds, nrows, False, 40)
# Verify data is visible and correct.
self.check(value_a, uri, nrows, None, 20)
self.check(value_b, uri, nrows, None, 30)
self.check(value_c, uri, nrows, None, 40)
# Pin the stable timestamp to 40. We will be validating the state of the data post-stable timestamp
# after we perform a recovery.
self.conn.set_timestamp('stable_timestamp=' + self.timestamp_str(40))
# Perform additional updates post-stable timestamp.
self.large_updates(uri, value_d, ds, nrows, False, 50)
self.large_updates(uri, value_a, ds, nrows, False, 60)
self.large_updates(uri, value_b, ds, nrows, False, 70)
# Verify additional updated data is visible and correct.
self.check(value_d, uri, nrows, None, 50)
self.check(value_a, uri, nrows, None, 60)
self.check(value_b, uri, nrows, None, 70)
# Checkpoint to ensure the data is flushed to disk.
self.session.checkpoint()
# Extract the most recent checkpoints write gen & run write gen. As we are still on a new DB connection,
# the run write gen should be 1 at this point, equal to the connection-wide base write gen.
# Since we checkpointed after a series of large writes/updates, the write gen of the pages should
# definitely be greater than 1.
checkpoint_write_gen, checkpoint_run_write_gen = self.parse_write_gen("file:test_debug_mode10.wt")
self.assertEqual(checkpoint_run_write_gen, 1)
self.assertGreater(checkpoint_write_gen, checkpoint_run_write_gen)
# Simulate a crash/restart, opening our new DB in recovery. As we open in recovery we want to additionally
# use the 'update_restore_evict' debug option to trigger update restore eviction.
self.conn_config = self.conn_config + self.conn_recon
simulate_crash_restart(self, ".", "RESTART")
# As we've created a new DB connection post-shutdown, the connection-wide
# base write gen should eventually initialise from the previous checkpoint's base 'write_gen' during the recovery process
# ('write_gen'+1). This should be reflected in the initialisation of the 'run_write_gen' field of the newest
# checkpoint post-recovery. As the recovery/rts process updates our pages, we'd also expect the latest checkpoint's
# 'write_gen' to again be greater than its 'run_write_gen'.
recovery_write_gen, recovery_run_write_gen = self.parse_write_gen("file:test_debug_mode10.wt")
self.assertGreater(recovery_run_write_gen, checkpoint_write_gen)
self.assertGreater(recovery_write_gen, recovery_run_write_gen)
# Read the statistics of pages that have been update restored (to check the mechanism was used).
stat_cursor = self.session.open_cursor('statistics:')
pages_update_restored = stat_cursor[stat.conn.cache_write_restore][2]
stat_cursor.close()
self.assertGreater(pages_update_restored, 0)
# Check that after recovery, we see the correct data with respect to our previous stable timestamp (40).
self.check(value_c, uri, nrows, None, 40)
self.check(value_c, uri, nrows, None, 50)
self.check(value_c, uri, nrows, None, 60)
self.check(value_c, uri, nrows, None, 70)
self.check(value_b, uri, nrows, None, 30)
self.check(value_a, uri, nrows, None, 20)
# Passing 0 results in opening a transaction with no read timestamp.
self.check(value_c, uri, nrows, None, 0)
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