Files
neon/test_runner/batch_others/test_branch_behind.py
Konstantin Knizhnik b227c63edf Set proper xl_prev in basebackup, when possible.
In a passing fix two minor issues with basabackup:
* check that we can't create branches with pre-initdb LSN's
* normalize branch LSN's that are pointing to the segment boundary

patch by @knizhnik
closes #506
2021-09-03 14:58:59 +03:00

93 lines
3.4 KiB
Python

import subprocess
from fixtures.zenith_fixtures import PostgresFactory, ZenithPageserver
pytest_plugins = ("fixtures.zenith_fixtures")
#
# Create a couple of branches off the main branch, at a historical point in time.
#
def test_branch_behind(zenith_cli, pageserver: ZenithPageserver, postgres: PostgresFactory, pg_bin):
# Branch at the point where only 100 rows were inserted
zenith_cli.run(["branch", "test_branch_behind", "empty"])
pgmain = postgres.create_start('test_branch_behind')
print("postgres is running on 'test_branch_behind' branch")
main_pg_conn = pgmain.connect()
main_cur = main_pg_conn.cursor()
# Create table, and insert the first 100 rows
main_cur.execute('CREATE TABLE foo (t text)')
main_cur.execute('''
INSERT INTO foo
SELECT 'long string to consume some space' || g
FROM generate_series(1, 100) g
''')
main_cur.execute('SELECT pg_current_wal_insert_lsn()')
lsn_a = main_cur.fetchone()[0]
print('LSN after 100 rows: ' + lsn_a)
# Insert some more rows. (This generates enough WAL to fill a few segments.)
main_cur.execute('''
INSERT INTO foo
SELECT 'long string to consume some space' || g
FROM generate_series(1, 100000) g
''')
main_cur.execute('SELECT pg_current_wal_insert_lsn()')
lsn_b = main_cur.fetchone()[0]
print('LSN after 100100 rows: ' + lsn_b)
# Branch at the point where only 100 rows were inserted
zenith_cli.run(["branch", "test_branch_behind_hundred", "test_branch_behind@" + lsn_a])
# Insert many more rows. This generates enough WAL to fill a few segments.
main_cur.execute('''
INSERT INTO foo
SELECT 'long string to consume some space' || g
FROM generate_series(1, 100000) g
''')
main_cur.execute('SELECT pg_current_wal_insert_lsn()')
main_cur.execute('SELECT pg_current_wal_insert_lsn()')
lsn_c = main_cur.fetchone()[0]
print('LSN after 200100 rows: ' + lsn_c)
# Branch at the point where only 200 rows were inserted
zenith_cli.run(["branch", "test_branch_behind_more", "test_branch_behind@" + lsn_b])
pg_hundred = postgres.create_start("test_branch_behind_hundred")
pg_more = postgres.create_start("test_branch_behind_more")
# On the 'hundred' branch, we should see only 100 rows
hundred_pg_conn = pg_hundred.connect()
hundred_cur = hundred_pg_conn.cursor()
hundred_cur.execute('SELECT count(*) FROM foo')
assert hundred_cur.fetchone() == (100, )
# On the 'more' branch, we should see 100200 rows
more_pg_conn = pg_more.connect()
more_cur = more_pg_conn.cursor()
more_cur.execute('SELECT count(*) FROM foo')
assert more_cur.fetchone() == (100100, )
# All the rows are visible on the main branch
main_cur.execute('SELECT count(*) FROM foo')
assert main_cur.fetchone() == (200100, )
# Check bad lsn's for branching
# branch at segment boundary
zenith_cli.run(["branch", "test_branch_segment_boundary", "test_branch_behind@0/3000000"])
pg = postgres.create_start("test_branch_segment_boundary")
cur = pg.connect().cursor()
cur.execute('SELECT 1')
assert cur.fetchone() == (1, )
# branch at pre-initdb lsn
try:
zenith_cli.run(["branch", "test_branch_preinitdb", "test_branch_behind@0/42"])
except subprocess.CalledProcessError:
print("Branch creation with pre-initdb LSN failed (as expected)")