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7aba299dbd
to avoid a subtle race condition. Without safekeeper, walreceiver reconnection can stuck, because of IO deadlock between walsender auth and regular backend.
135 lines
5.0 KiB
Python
135 lines
5.0 KiB
Python
import subprocess
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from contextlib import closing
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import psycopg2.extras
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import pytest
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from fixtures.log_helper import log
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from fixtures.utils import print_gc_result
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from fixtures.zenith_fixtures import ZenithEnvBuilder
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pytest_plugins = ("fixtures.zenith_fixtures")
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#
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# Create a couple of branches off the main branch, at a historical point in time.
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#
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def test_branch_behind(zenith_env_builder: ZenithEnvBuilder):
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# Use safekeeper in this test to avoid a subtle race condition.
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# Without safekeeper, walreceiver reconnection can stuck
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# because of IO deadlock.
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#
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# See https://github.com/zenithdb/zenith/issues/1068
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zenith_env_builder.num_safekeepers = 1
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env = zenith_env_builder.init()
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# Branch at the point where only 100 rows were inserted
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env.zenith_cli(["branch", "test_branch_behind", "main"])
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pgmain = env.postgres.create_start('test_branch_behind')
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log.info("postgres is running on 'test_branch_behind' branch")
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main_pg_conn = pgmain.connect()
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main_cur = main_pg_conn.cursor()
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main_cur.execute("SHOW zenith.zenith_timeline")
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timeline = main_cur.fetchone()[0]
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# Create table, and insert the first 100 rows
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main_cur.execute('CREATE TABLE foo (t text)')
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# keep some early lsn to test branch creation on out of date lsn
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main_cur.execute('SELECT pg_current_wal_insert_lsn()')
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gced_lsn = main_cur.fetchone()[0]
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main_cur.execute('''
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INSERT INTO foo
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SELECT 'long string to consume some space' || g
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FROM generate_series(1, 100) g
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''')
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main_cur.execute('SELECT pg_current_wal_insert_lsn()')
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lsn_a = main_cur.fetchone()[0]
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log.info(f'LSN after 100 rows: {lsn_a}')
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# Insert some more rows. (This generates enough WAL to fill a few segments.)
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main_cur.execute('''
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INSERT INTO foo
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SELECT 'long string to consume some space' || g
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FROM generate_series(1, 200000) g
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''')
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main_cur.execute('SELECT pg_current_wal_insert_lsn()')
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lsn_b = main_cur.fetchone()[0]
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log.info(f'LSN after 200100 rows: {lsn_b}')
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# Branch at the point where only 100 rows were inserted
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env.zenith_cli(["branch", "test_branch_behind_hundred", "test_branch_behind@" + lsn_a])
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# Insert many more rows. This generates enough WAL to fill a few segments.
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main_cur.execute('''
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INSERT INTO foo
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SELECT 'long string to consume some space' || g
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FROM generate_series(1, 200000) g
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''')
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main_cur.execute('SELECT pg_current_wal_insert_lsn()')
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main_cur.execute('SELECT pg_current_wal_insert_lsn()')
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lsn_c = main_cur.fetchone()[0]
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log.info(f'LSN after 400100 rows: {lsn_c}')
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# Branch at the point where only 200100 rows were inserted
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env.zenith_cli(["branch", "test_branch_behind_more", "test_branch_behind@" + lsn_b])
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pg_hundred = env.postgres.create_start("test_branch_behind_hundred")
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pg_more = env.postgres.create_start("test_branch_behind_more")
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# On the 'hundred' branch, we should see only 100 rows
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hundred_pg_conn = pg_hundred.connect()
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hundred_cur = hundred_pg_conn.cursor()
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hundred_cur.execute('SELECT count(*) FROM foo')
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assert hundred_cur.fetchone() == (100, )
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# On the 'more' branch, we should see 100200 rows
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more_pg_conn = pg_more.connect()
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more_cur = more_pg_conn.cursor()
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more_cur.execute('SELECT count(*) FROM foo')
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assert more_cur.fetchone() == (200100, )
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# All the rows are visible on the main branch
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main_cur.execute('SELECT count(*) FROM foo')
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assert main_cur.fetchone() == (400100, )
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# Check bad lsn's for branching
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# branch at segment boundary
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env.zenith_cli(["branch", "test_branch_segment_boundary", "test_branch_behind@0/3000000"])
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pg = env.postgres.create_start("test_branch_segment_boundary")
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cur = pg.connect().cursor()
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cur.execute('SELECT 1')
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assert cur.fetchone() == (1, )
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# branch at pre-initdb lsn
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with pytest.raises(Exception, match="invalid branch start lsn"):
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env.zenith_cli(["branch", "test_branch_preinitdb", "test_branch_behind@0/42"])
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# check that we cannot create branch based on garbage collected data
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with closing(env.pageserver.connect()) as psconn:
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with psconn.cursor(cursor_factory=psycopg2.extras.DictCursor) as pscur:
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# call gc to advace latest_gc_cutoff_lsn
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pscur.execute(f"do_gc {env.initial_tenant} {timeline} 0")
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row = pscur.fetchone()
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print_gc_result(row)
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with pytest.raises(Exception, match="invalid branch start lsn"):
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# this gced_lsn is pretty random, so if gc is disabled this woudln't fail
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env.zenith_cli(["branch", "test_branch_create_fail", f"test_branch_behind@{gced_lsn}"])
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# check that after gc everything is still there
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hundred_cur.execute('SELECT count(*) FROM foo')
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assert hundred_cur.fetchone() == (100, )
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more_cur.execute('SELECT count(*) FROM foo')
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assert more_cur.fetchone() == (200100, )
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main_cur.execute('SELECT count(*) FROM foo')
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assert main_cur.fetchone() == (400100, )
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