Add extension neon to all databases.

- Run CREATE EXTENSION neon for template1, so that it was created in all databases.
- Run ALTER EXTENSION neon in all databases, to always have the newest version of the extension in computes.
- Add test_neon_extension test

test_runner/regress/test_backpressure.py

@@ -24,8 +24,6 @@ def check_backpressure(endpoint: Endpoint, stop_event: threading.Event, polling_
     log.info("checks started")
 
     with pg_cur(endpoint) as cur:
-        cur.execute("CREATE EXTENSION neon")  # TODO move it to neon_fixtures?
-
         cur.execute("select pg_size_bytes(current_setting('max_replication_write_lag'))")
         res = cur.fetchone()
         max_replication_write_lag_bytes = res[0]
@@ -102,9 +100,13 @@ def test_backpressure_received_lsn_lag(neon_env_builder: NeonEnvBuilder):
     # Create a branch for us
     env.neon_cli.create_branch("test_backpressure")
 
-    endpoint = env.endpoints.create_start(
+    endpoint = env.endpoints.create(
         "test_backpressure", config_lines=["max_replication_write_lag=30MB"]
     )
+    # don't skip pg_catalog updates - it runs CREATE EXTENSION neon
+    # which is needed for backpressure_lsns() to work
+    endpoint.respec(skip_pg_catalog_updates=False)
+    endpoint.start()
     log.info("postgres is running on 'test_backpressure' branch")
 
     # setup check thread

test_runner/regress/test_neon_extension.py

@@ -0,0 +1,38 @@
+from contextlib import closing
+
+from fixtures.log_helper import log
+from fixtures.neon_fixtures import NeonEnvBuilder
+
+
+# Verify that the neon extension is installed and has the correct version.
+def test_neon_extension(neon_env_builder: NeonEnvBuilder):
+    env = neon_env_builder.init_start()
+    env.neon_cli.create_branch("test_create_extension_neon")
+
+    endpoint_main = env.endpoints.create("test_create_extension_neon")
+    # don't skip pg_catalog updates - it runs CREATE EXTENSION neon
+    endpoint_main.respec(skip_pg_catalog_updates=False)
+    endpoint_main.start()
+
+    log.info("postgres is running on 'test_create_extension_neon' branch")
+
+    with closing(endpoint_main.connect()) as conn:
+        with conn.cursor() as cur:
+            cur.execute("SELECT extversion from pg_extension where extname='neon'")
+            # If this fails, it means the extension is either not installed
+            # or was updated and the version is different.
+            #
+            # IMPORTANT:
+            # If the version has changed, the test should be updated.
+            # Ensure that the default version is also updated in the neon.control file
+            assert cur.fetchone() == ("1.0",)
+
+            # create test database
+            cur.execute("CREATE DATABASE foodb")
+
+    # connect to test database
+    # test that neon extension is installed and has the correct version
+    with closing(endpoint_main.connect(dbname="foodb")) as conn:
+        with conn.cursor() as cur:
+            cur.execute("SELECT extversion from pg_extension where extname='neon'")
+            assert cur.fetchone() == ("1.0",)

test_runner/regress/test_timeline_size.py

@@ -152,17 +152,20 @@ def test_timeline_size_quota(neon_env_builder: NeonEnvBuilder):
 
     wait_for_timeline_size_init(client, tenant=env.initial_tenant, timeline=new_timeline_id)
 
-    endpoint_main = env.endpoints.create_start(
+    endpoint_main = env.endpoints.create(
         "test_timeline_size_quota",
         # Set small limit for the test
         config_lines=["neon.max_cluster_size=30MB"],
     )
+    # don't skip pg_catalog updates - it runs CREATE EXTENSION neon
+    # which is needed for pg_cluster_size() to work
+    endpoint_main.respec(skip_pg_catalog_updates=False)
+    endpoint_main.start()
+
     log.info("postgres is running on 'test_timeline_size_quota' branch")
 
     with closing(endpoint_main.connect()) as conn:
         with conn.cursor() as cur:
-            cur.execute("CREATE EXTENSION neon")  # TODO move it to neon_fixtures?
-
             cur.execute("CREATE TABLE foo (t text)")
 
             wait_for_pageserver_catchup(endpoint_main)