Add bulk update test (#2902)

test_runner/performance/test_bulk_update.py

@@ -0,0 +1,62 @@
+import pytest
+from fixtures.neon_fixtures import NeonEnvBuilder, wait_for_last_flush_lsn
+
+
+#
+# Benchmark effect of prefetch on bulk update operations
+#
+# A sequential scan that's part of a bulk update is the same as any other sequential scan,
+# but dirtying the pages as you go affects the last-written LSN tracking. We used to have
+# an issue with the last-written LSN cache where rapidly evicting dirty pages always
+# invalidated the prefetched responses, which showed up in bad performance in this test.
+#
+@pytest.mark.timeout(10000)
+@pytest.mark.parametrize("fillfactor", [10, 50, 100])
+def test_bulk_update(neon_env_builder: NeonEnvBuilder, zenbenchmark, fillfactor):
+
+    env = neon_env_builder.init_start()
+    n_records = 1000000
+
+    timeline_id = env.neon_cli.create_branch("test_bulk_update")
+    tenant_id = env.initial_tenant
+    pg = env.postgres.create_start("test_bulk_update")
+    cur = pg.connect().cursor()
+    cur.execute("set statement_timeout=0")
+
+    cur.execute(f"create table t(x integer) WITH (fillfactor={fillfactor})")
+
+    with zenbenchmark.record_duration("insert-1"):
+        cur.execute(f"insert into t values (generate_series(1,{n_records}))")
+
+    cur.execute("vacuum t")
+    wait_for_last_flush_lsn(env, pg, tenant_id, timeline_id)
+
+    with zenbenchmark.record_duration("update-no-prefetch"):
+        cur.execute("update t set x=x+1")
+
+    cur.execute("vacuum t")
+    wait_for_last_flush_lsn(env, pg, tenant_id, timeline_id)
+
+    with zenbenchmark.record_duration("delete-no-prefetch"):
+        cur.execute("delete from t")
+
+    cur.execute("drop table t")
+    cur.execute("set enable_seqscan_prefetch=on")
+    cur.execute("set seqscan_prefetch_buffers=100")
+
+    cur.execute(f"create table t2(x integer) WITH (fillfactor={fillfactor})")
+
+    with zenbenchmark.record_duration("insert-2"):
+        cur.execute(f"insert into t2 values (generate_series(1,{n_records}))")
+
+    cur.execute("vacuum t2")
+    wait_for_last_flush_lsn(env, pg, tenant_id, timeline_id)
+
+    with zenbenchmark.record_duration("update-with-prefetch"):
+        cur.execute("update t2 set x=x+1")
+
+    cur.execute("vacuum t2")
+    wait_for_last_flush_lsn(env, pg, tenant_id, timeline_id)
+
+    with zenbenchmark.record_duration("delete-with-prefetch"):
+        cur.execute("delete from t2")