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133 lines
5.0 KiB
Python
133 lines
5.0 KiB
Python
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.neon_fixtures import NeonEnvBuilder
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from fixtures.utils import print_gc_result, query_scalar
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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(neon_env_builder: NeonEnvBuilder):
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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/neondatabase/neon/issues/1068
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neon_env_builder.num_safekeepers = 1
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# Disable pitr, because here we want to test branch creation after GC
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neon_env_builder.pageserver_config_override = "tenant_config={pitr_interval = '0 sec'}"
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env = neon_env_builder.init_start()
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# Branch at the point where only 100 rows were inserted
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env.neon_cli.create_branch("test_branch_behind")
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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_cur = pgmain.connect().cursor()
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timeline = query_scalar(main_cur, "SHOW neon.timeline_id")
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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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gced_lsn = query_scalar(main_cur, "SELECT pg_current_wal_insert_lsn()")
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main_cur.execute(
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"""
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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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)
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lsn_a = query_scalar(main_cur, "SELECT pg_current_wal_insert_lsn()")
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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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"""
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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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)
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lsn_b = query_scalar(main_cur, "SELECT pg_current_wal_insert_lsn()")
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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.neon_cli.create_branch(
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"test_branch_behind_hundred", "test_branch_behind", ancestor_start_lsn=lsn_a
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)
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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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"""
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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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)
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lsn_c = query_scalar(main_cur, "SELECT pg_current_wal_insert_lsn()")
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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.neon_cli.create_branch(
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"test_branch_behind_more", "test_branch_behind", ancestor_start_lsn=lsn_b
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)
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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_cur = pg_hundred.connect().cursor()
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assert query_scalar(hundred_cur, "SELECT count(*) FROM foo") == 100
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# On the 'more' branch, we should see 100200 rows
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more_cur = pg_more.connect().cursor()
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assert query_scalar(more_cur, "SELECT count(*) FROM foo") == 200100
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# All the rows are visible on the main branch
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assert query_scalar(main_cur, "SELECT count(*) FROM foo") == 400100
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# Check bad lsn's for branching
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# branch at segment boundary
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env.neon_cli.create_branch(
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"test_branch_segment_boundary", "test_branch_behind", ancestor_start_lsn="0/3000000"
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)
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pg = env.postgres.create_start("test_branch_segment_boundary")
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assert pg.safe_psql("SELECT 1")[0][0] == 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.neon_cli.create_branch("test_branch_preinitdb", ancestor_start_lsn="0/42")
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# branch at pre-ancestor lsn
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with pytest.raises(Exception, match="less than timeline ancestor lsn"):
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env.neon_cli.create_branch(
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"test_branch_preinitdb", "test_branch_behind", ancestor_start_lsn="0/42"
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)
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# check that we cannot create branch based on garbage collected data
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with env.pageserver.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.hex} {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.neon_cli.create_branch(
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"test_branch_create_fail", "test_branch_behind", ancestor_start_lsn=gced_lsn
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)
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# check that after gc everything is still there
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assert query_scalar(hundred_cur, "SELECT count(*) FROM foo") == 100
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assert query_scalar(more_cur, "SELECT count(*) FROM foo") == 200100
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assert query_scalar(main_cur, "SELECT count(*) FROM foo") == 400100
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