Add test_multixact to check that we replay multixact and advance next_multixact_id correctly

test_runner/batch_others/test_multixact.py

@@ -0,0 +1,71 @@
+import pytest
+import os
+import psycopg2
+import multiprocessing
+
+pytest_plugins = ("fixtures.zenith_fixtures")
+
+#
+# Test multixact state after branching
+# Now this test is very minimalistic -
+# it only checks next_multixact_id field in restored pg_control,
+# since we don't have functions to check multixact internals.
+#
+
+def runQuery(connstr):
+    con = psycopg2.connect(connstr) 
+    con.set_isolation_level(psycopg2.extensions.ISOLATION_LEVEL_AUTOCOMMIT)
+    cur = con.cursor()
+    cur.execute('select * from t1 for key share;') 
+
+
+def test_multixact(pageserver, postgres, pg_bin, zenith_cli, base_dir):
+
+    # Create a branch for us
+    zenith_cli.run(["branch", "test_multixact", "empty"])
+    pg = postgres.create_start('test_multixact')
+
+    print("postgres is running on 'test_multixact' branch")
+    pg_conn = psycopg2.connect(pg.connstr())
+    pg_conn.set_isolation_level(psycopg2.extensions.ISOLATION_LEVEL_AUTOCOMMIT)
+    cur = pg_conn.cursor()
+
+    cur.execute('CREATE TABLE t1(i int primary key);'
+    'INSERT INTO t1 select * from generate_series(1,100);')
+
+    cur.execute('SELECT next_multixact_id FROM pg_control_checkpoint();')
+    next_multixact_id_old = cur.fetchone()[0]
+
+    # Lock entries in parallel connections to set multixact
+    nclients = 3
+    pool = multiprocessing.Pool(nclients)
+    args = [pg.connstr()] * nclients
+    pool.map(runQuery, args)
+    pool.close()
+    pool.join()
+
+    # force wal flush
+    cur.execute('checkpoint')
+
+    cur.execute('SELECT next_multixact_id, pg_current_wal_flush_lsn() FROM pg_control_checkpoint();')
+    res = cur.fetchone()
+    next_multixact_id = res[0]
+    lsn = res[1]
+
+    # Ensure that we did lock some tuples
+    assert(int(next_multixact_id) > int(next_multixact_id_old))
+
+    # Branch at this point
+    zenith_cli.run(["branch", "test_multixact_new", "test_multixact@"+lsn]);
+    pg_new = postgres.create_start('test_multixact_new')
+
+    print("postgres is running on 'test_multixact_new' branch")
+    pg_new_conn = psycopg2.connect(pg_new.connstr())
+    pg_new_conn.set_isolation_level(psycopg2.extensions.ISOLATION_LEVEL_AUTOCOMMIT)
+    cur_new = pg_new_conn.cursor()
+
+    cur_new.execute('SELECT next_multixact_id FROM pg_control_checkpoint();')
+    next_multixact_id_new = cur_new.fetchone()[0]
+
+    # Check that we restored pg_controlfile correctly
+    assert(next_multixact_id_new == next_multixact_id)