Files
neon/test_runner/batch_others/test_multixact.py
Dmitry Rodionov 092a9b74d3 use only s3 in boto3-stubs and update mypy
Newer version of mypy fixes buggy error when trying to update only boto3 stubs.
However it brings new checks and starts to yell when we index into
cusror.fetchone without checking for None first. So this introduces a wrapper
to simplify quering for scalar values. I tried to use cursor_factory connection
argument but without success. There can be a better way to do that,
but this looks the simplest
2022-08-01 18:28:49 +03:00

75 lines
2.7 KiB
Python

from fixtures.neon_fixtures import NeonEnv, check_restored_datadir_content
from fixtures.log_helper import log
from fixtures.utils import query_scalar
#
# Test multixact state after branching
# Now this test is very minimalistic -
# it only checks next_multixact_id field in restored pg_control,
# since we don't have functions to check multixact internals.
#
def test_multixact(neon_simple_env: NeonEnv, test_output_dir):
env = neon_simple_env
env.neon_cli.create_branch('test_multixact', 'empty')
pg = env.postgres.create_start('test_multixact')
log.info("postgres is running on 'test_multixact' branch")
cur = pg.connect().cursor()
cur.execute('''
CREATE TABLE t1(i int primary key);
INSERT INTO t1 select * from generate_series(1, 100);
''')
next_multixact_id_old = query_scalar(cur,
'SELECT next_multixact_id FROM pg_control_checkpoint()')
# Lock entries using parallel connections in a round-robin fashion.
nclients = 20
connections = []
for i in range(nclients):
# Do not turn on autocommit. We want to hold the key-share locks.
conn = pg.connect(autocommit=False)
connections.append(conn)
# On each iteration, we commit the previous transaction on a connection,
# and issue antoher select. Each SELECT generates a new multixact that
# includes the new XID, and the XIDs of all the other parallel transactions.
# This generates enough traffic on both multixact offsets and members SLRUs
# to cross page boundaries.
for i in range(5000):
conn = connections[i % nclients]
conn.commit()
conn.cursor().execute('select * from t1 for key share')
# We have multixacts now. We can close the connections.
for c in connections:
c.close()
# force wal flush
cur.execute('checkpoint')
cur.execute(
'SELECT next_multixact_id, pg_current_wal_insert_lsn() FROM pg_control_checkpoint()')
res = cur.fetchone()
assert res is not None
next_multixact_id = res[0]
lsn = res[1]
# Ensure that we did lock some tuples
assert int(next_multixact_id) > int(next_multixact_id_old)
# Branch at this point
env.neon_cli.create_branch('test_multixact_new', 'test_multixact', ancestor_start_lsn=lsn)
pg_new = env.postgres.create_start('test_multixact_new')
log.info("postgres is running on 'test_multixact_new' branch")
next_multixact_id_new = pg_new.safe_psql(
'SELECT next_multixact_id FROM pg_control_checkpoint()')[0][0]
# Check that we restored pg_controlfile correctly
assert next_multixact_id_new == next_multixact_id
# Check that we can restore the content of the datadir correctly
check_restored_datadir_content(test_output_dir, env, pg)