Add a test for gc dropping active layers (#707)

Signed-off-by: Dhammika Pathirana <dhammika@gmail.com>
2026-07-04 12:40:37 +00:00 · 2022-04-10 14:05:59 -07:00
parent 65704708fa
commit 0664100755
1 changed files with 87 additions and 0 deletions
--- a/test_runner/batch_others/test_branch_and_gc.py
+++ b/test_runner/batch_others/test_branch_and_gc.py
@@ -0,0 +1,87 @@
+import subprocess
+import asyncio
+from contextlib import closing
+
+import psycopg2.extras
+import pytest
+from fixtures.log_helper import log
+from fixtures.zenith_fixtures import ZenithEnvBuilder
+
+
+#
+# Create a branches off the main branch and run gc.
+#
+def test_branch_and_gc(zenith_env_builder: ZenithEnvBuilder):
+
+    # Use safekeeper in this test to avoid a subtle race condition.
+    # Without safekeeper, walreceiver reconnection can stuck
+    # because of IO deadlock.
+    #
+    # See https://github.com/zenithdb/zenith/issues/1068
+    zenith_env_builder.num_safekeepers = 1
+    env = zenith_env_builder.init()
+
+    # Override defaults, 1M gc_horizon and 4M checkpoint_distance.
+    # Extend compaction_period and gc_period to disable background compaction and gc.
+    env.pageserver.start(overrides=[
+        '--pageserver-config-override="gc_period"="10 m"',
+        '--pageserver-config-override="gc_horizon"=1048576',
+        '--pageserver-config-override="checkpoint_distance"=4194304',
+        '--pageserver-config-override="compaction_period"="10 m"'
+    ])
+    env.safekeepers[0].start()
+
+    env.zenith_cli.create_branch('test_main')
+    pgmain = env.postgres.create_start('test_main')
+    log.info("postgres is running on 'test_main' branch")
+
+    main_cur = pgmain.connect().cursor()
+    main_cur.execute("SHOW zenith.zenith_timeline")
+    timeline = main_cur.fetchone()[0]
+
+    # Create table, and insert 100 rows.
+    main_cur.execute('CREATE TABLE foo (t text) WITH (autovacuum_enabled = off)')
+    main_cur.execute('SELECT pg_current_wal_insert_lsn()')
+    init_lsn = main_cur.fetchone()[0]
+    main_cur.execute('''
+        INSERT INTO foo
+            SELECT '00112233445566778899AABBCCDDEEFF' || ':main:' || g
+            FROM generate_series(1, 100) g
+    ''')
+    main_cur.execute('SELECT pg_current_wal_insert_lsn()')
+    lsn_100 = main_cur.fetchone()[0]
+    log.info(f'LSN after 100 rows: {lsn_100}')
+
+    # Create branch.
+    env.zenith_cli.create_branch('test_branch', 'test_main', ancestor_start_lsn=lsn_100)
+    pg_branch = env.postgres.create_start('test_branch')
+
+    # Append more rows to generate multiple layers in ancestor's branch.
+    main_cur.execute('''
+        INSERT INTO foo
+            SELECT '00112233445566778899AABBCCDDEEFF' || ':main:' || g
+            FROM generate_series(1, 200000) g
+    ''')
+    main_cur.execute('SELECT pg_current_wal_insert_lsn()')
+    lsn_200100 = main_cur.fetchone()[0]
+    log.info(f'LSN after 400100 rows: {lsn_200100}')
+
+    # Run gc on main branch at current lsn.
+    psconn = env.pageserver.connect()
+    psconn.cursor().execute(f'''do_gc {env.initial_tenant.hex} {timeline} {lsn_200100}''')
+
+    # Insert some rows on descendent's branch to diverge.
+    branch_cur = pg_branch.connect().cursor()
+    branch_cur.execute("SHOW zenith.zenith_timeline")
+    branch_timeline = branch_cur.fetchone()[0]
+    branch_cur.execute('''
+        INSERT INTO foo
+            SELECT '00112233445566778899AABBCCDDEEFF' || ':branch:' || g
+            FROM generate_series(1, 100) g
+    ''')
+    branch_cur.execute('SELECT pg_current_wal_insert_lsn()')
+    lsn_branch_200 = branch_cur.fetchone()[0]
+    log.info(f'LSN after 200 rows on branch: {lsn_branch_200}')
+
+    branch_cur.execute('SELECT count(*) FROM foo')
+    assert branch_cur.fetchone() == (200, )