mirror of
https://github.com/neondatabase/neon.git
synced 2026-01-07 21:42:56 +00:00
66ec135676
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.
69 lines
2.8 KiB
Python
69 lines
2.8 KiB
Python
from contextlib import closing
|
|
|
|
from fixtures.zenith_fixtures import ZenithEnv
|
|
from fixtures.log_helper import log
|
|
|
|
pytest_plugins = ("fixtures.zenith_fixtures")
|
|
|
|
|
|
#
|
|
# Test where Postgres generates a lot of WAL, and it's garbage collected away, but
|
|
# no pages are evicted so that Postgres uses an old LSN in a GetPage request.
|
|
# We had a bug where the page server failed to find the page version because it
|
|
# thought it was already garbage collected away, because the LSN in the GetPage
|
|
# request was very old and the WAL from that time was indeed already removed.
|
|
# In reality, the LSN on a GetPage request coming from a primary server is
|
|
# just a hint that the page hasn't been modified since that LSN, and the page
|
|
# server should return the latest page version regardless of the LSN.
|
|
#
|
|
def test_old_request_lsn(zenith_simple_env: ZenithEnv):
|
|
env = zenith_simple_env
|
|
# Create a branch for us
|
|
env.zenith_cli(["branch", "test_old_request_lsn", "empty"])
|
|
pg = env.postgres.create_start('test_old_request_lsn')
|
|
log.info('postgres is running on test_old_request_lsn branch')
|
|
|
|
pg_conn = pg.connect()
|
|
cur = pg_conn.cursor()
|
|
|
|
# Get the timeline ID of our branch. We need it for the 'do_gc' command
|
|
cur.execute("SHOW zenith.zenith_timeline")
|
|
timeline = cur.fetchone()[0]
|
|
|
|
psconn = env.pageserver.connect()
|
|
pscur = psconn.cursor()
|
|
|
|
# Create table, and insert some rows. Make it big enough that it doesn't fit in
|
|
# shared_buffers.
|
|
cur.execute('CREATE TABLE foo (id int4 PRIMARY KEY, val int, t text)')
|
|
cur.execute('''
|
|
INSERT INTO foo
|
|
SELECT g, 1, 'long string to consume some space' || g
|
|
FROM generate_series(1, 100000) g
|
|
''')
|
|
|
|
# Verify that the table is larger than shared_buffers, so that the SELECT below
|
|
# will cause GetPage requests.
|
|
cur.execute('''
|
|
select setting::int * pg_size_bytes(unit) as shared_buffers, pg_relation_size('foo') as tbl_ize
|
|
from pg_settings where name = 'shared_buffers'
|
|
''')
|
|
row = cur.fetchone()
|
|
log.info(f'shared_buffers is {row[0]}, table size {row[1]}')
|
|
assert int(row[0]) < int(row[1])
|
|
|
|
cur.execute('VACUUM foo')
|
|
|
|
# Make a lot of updates on a single row, generating a lot of WAL. Trigger
|
|
# garbage collections so that the page server will remove old page versions.
|
|
for i in range(10):
|
|
pscur.execute(f"do_gc {env.initial_tenant} {timeline} 0")
|
|
for j in range(100):
|
|
cur.execute('UPDATE foo SET val = val + 1 WHERE id = 1;')
|
|
|
|
# All (or at least most of) the updates should've been on the same page, so
|
|
# that we haven't had to evict any dirty pages for a long time. Now run
|
|
# a query that sends GetPage@LSN requests with the old LSN.
|
|
cur.execute("SELECT COUNT(*), SUM(val) FROM foo")
|
|
assert cur.fetchone() == (100000, 101000)
|