From df086cd139ee5ecc82bf096fc3fc6ee4397ac983 Mon Sep 17 00:00:00 2001
From: Sasha Krassovsky <sasha@neon.tech>
Date: Thu, 15 Aug 2024 15:34:45 -0700
Subject: [PATCH] Add logical replication test to exercise snapfiles (#8364)

---
 .../performance/test_logical_replication.py   | 82 +++++++++++++++++++
 1 file changed, 82 insertions(+)

diff --git a/test_runner/performance/test_logical_replication.py b/test_runner/performance/test_logical_replication.py
index 4b4ffc1fee..c4e42a7834 100644
--- a/test_runner/performance/test_logical_replication.py
+++ b/test_runner/performance/test_logical_replication.py
@@ -262,3 +262,85 @@ def test_publisher_restart(
             sub_workload.terminate()
     finally:
         pub_workload.terminate()
+
+
+@pytest.mark.remote_cluster
+@pytest.mark.timeout(2 * 60 * 60)
+def test_snap_files(
+    pg_bin: PgBin,
+    benchmark_project_pub: NeonApiEndpoint,
+    zenbenchmark: NeonBenchmarker,
+):
+    """
+    Creates a node with a replication slot. Generates pgbench into the replication slot,
+    then runs pgbench inserts while generating large numbers of snapfiles. Then restarts
+    the node and tries to peek the replication changes.
+    """
+    test_duration_min = 60
+    test_interval_min = 5
+    pgbench_duration = f"-T{test_duration_min * 60 * 2}"
+
+    env = benchmark_project_pub.pgbench_env
+    connstr = benchmark_project_pub.connstr
+    pg_bin.run_capture(["pgbench", "-i", "-s100"], env=env)
+
+    with psycopg2.connect(connstr) as conn:
+        conn.autocommit = True
+        with conn.cursor() as cur:
+            cur.execute("SELECT rolsuper FROM pg_roles WHERE rolname = 'neondb_owner'")
+            is_super = cur.fetchall()[0]
+            assert is_super, "This benchmark won't work if we don't have superuser"
+
+    conn = psycopg2.connect(connstr)
+    conn.autocommit = True
+    cur = conn.cursor()
+    cur.execute("ALTER SYSTEM SET neon.logical_replication_max_snap_files = -1")
+
+    with psycopg2.connect(connstr) as conn:
+        conn.autocommit = True
+        with conn.cursor() as cur:
+            cur.execute("SELECT pg_reload_conf()")
+
+    with psycopg2.connect(connstr) as conn:
+        conn.autocommit = True
+        with conn.cursor() as cur:
+            cur.execute(
+                """
+                DO $$
+                    BEGIN
+                    IF EXISTS (
+                        SELECT 1
+                        FROM pg_replication_slots
+                        WHERE slot_name = 'slotter'
+                    ) THEN
+                        PERFORM pg_drop_replication_slot('slotter');
+                    END IF;
+                END $$;
+            """
+            )
+            cur.execute("SELECT pg_create_logical_replication_slot('slotter', 'test_decoding')")
+
+    workload = pg_bin.run_nonblocking(["pgbench", "-c10", pgbench_duration, "-Mprepared"], env=env)
+    try:
+        start = time.time()
+        prev_measurement = time.time()
+        while time.time() - start < test_duration_min * 60:
+            with psycopg2.connect(connstr) as conn:
+                with conn.cursor() as cur:
+                    cur.execute(
+                        "SELECT count(*) FROM (SELECT pg_log_standby_snapshot() FROM generate_series(1, 10000) g) s"
+                    )
+                    check_pgbench_still_running(workload)
+                    cur.execute(
+                        "SELECT pg_replication_slot_advance('slotter', pg_current_wal_lsn())"
+                    )
+
+            # Measure storage
+            if time.time() - prev_measurement > test_interval_min * 60:
+                storage = benchmark_project_pub.get_synthetic_storage_size()
+                zenbenchmark.record("storage", storage, "B", MetricReport.LOWER_IS_BETTER)
+                prev_measurement = time.time()
+            time.sleep(test_interval_min * 60 / 3)
+
+    finally:
+        workload.terminate()