Files
neon/test_runner/batch_others/test_vm_bits.py
Heikki Linnakangas 66ec135676 Refactor pytest fixtures
Instead of having a lot of separate fixtures for setting up the page
server, the compute nodes, the safekeepers etc., have one big ZenithEnv
object that encapsulates the whole environment. Every test either uses
a shared "zenith_simple_env" fixture, which contains the default setup
of a pageserver with no authentication, and no safekeepers. Tests that
want to use safekeepers or authentication set up a custom test-specific
ZenithEnv fixture.

Gathering information about the whole environment into one object makes
some things simpler. For example, when a new compute node is created,
you no longer need to pass the 'wal_acceptors' connection string as
argument to the 'postgres.create_start' function. The 'create_start'
function fetches that information directly from the ZenithEnv object.
2021-10-25 14:14:47 +03:00

83 lines
2.9 KiB
Python

from fixtures.zenith_fixtures import ZenithEnv
from fixtures.log_helper import log
pytest_plugins = ("fixtures.zenith_fixtures")
#
# Test that the VM bit is cleared correctly at a HEAP_DELETE and
# HEAP_UPDATE record.
#
def test_vm_bit_clear(zenith_simple_env: ZenithEnv):
env = zenith_simple_env
# Create a branch for us
env.zenith_cli(["branch", "test_vm_bit_clear", "empty"])
pg = env.postgres.create_start('test_vm_bit_clear')
log.info("postgres is running on 'test_vm_bit_clear' branch")
pg_conn = pg.connect()
cur = pg_conn.cursor()
# Install extension containing function needed for test
cur.execute('CREATE EXTENSION zenith_test_utils')
# Create a test table and freeze it to set the VM bit.
cur.execute('CREATE TABLE vmtest_delete (id integer PRIMARY KEY)')
cur.execute('INSERT INTO vmtest_delete VALUES (1)')
cur.execute('VACUUM FREEZE vmtest_delete')
cur.execute('CREATE TABLE vmtest_update (id integer PRIMARY KEY)')
cur.execute('INSERT INTO vmtest_update SELECT g FROM generate_series(1, 1000) g')
cur.execute('VACUUM FREEZE vmtest_update')
# DELETE and UDPATE the rows.
cur.execute('DELETE FROM vmtest_delete WHERE id = 1')
cur.execute('UPDATE vmtest_update SET id = 5000 WHERE id = 1')
# Branch at this point, to test that later
env.zenith_cli(["branch", "test_vm_bit_clear_new", "test_vm_bit_clear"])
# Clear the buffer cache, to force the VM page to be re-fetched from
# the page server
cur.execute('SELECT clear_buffer_cache()')
# Check that an index-only scan doesn't see the deleted row. If the
# clearing of the VM bit was not replayed correctly, this would incorrectly
# return deleted row.
cur.execute('''
set enable_seqscan=off;
set enable_indexscan=on;
set enable_bitmapscan=off;
''')
cur.execute('SELECT * FROM vmtest_delete WHERE id = 1')
assert (cur.fetchall() == [])
cur.execute('SELECT * FROM vmtest_update WHERE id = 1')
assert (cur.fetchall() == [])
cur.close()
# Check the same thing on the branch that we created right after the DELETE
#
# As of this writing, the code in smgrwrite() creates a full-page image whenever
# a dirty VM page is evicted. If the VM bit was not correctly cleared by the
# earlier WAL record, the full-page image hides the problem. Starting a new
# server at the right point-in-time avoids that full-page image.
pg_new = env.postgres.create_start('test_vm_bit_clear_new')
log.info("postgres is running on 'test_vm_bit_clear_new' branch")
pg_new_conn = pg_new.connect()
cur_new = pg_new_conn.cursor()
cur_new.execute('''
set enable_seqscan=off;
set enable_indexscan=on;
set enable_bitmapscan=off;
''')
cur_new.execute('SELECT * FROM vmtest_delete WHERE id = 1')
assert (cur_new.fetchall() == [])
cur_new.execute('SELECT * FROM vmtest_update WHERE id = 1')
assert (cur_new.fetchall() == [])