Feat/postgres 16 (#4761)

This adds PostgreSQL 16 as a vendored postgresql version, and adapts the
code to support this version. 
The important changes to PostgreSQL 16 compared to the PostgreSQL 15
changeset include the addition of a neon_rmgr instead of altering Postgres's
original WAL format.

Co-authored-by: Alexander Bayandin <alexander@neon.tech>
Co-authored-by: Heikki Linnakangas <heikki@neon.tech>

test_runner/fixtures/neon_fixtures.py

@@ -1583,6 +1583,7 @@ class NeonPageserver(PgProtocol):
             ".*took more than expected to complete.*",
             # these can happen during shutdown, but it should not be a reason to fail a test
             ".*completed, took longer than expected.*",
+            '.*registered custom resource manager "neon".*',
         ]
 
     def start(

test_runner/fixtures/pg_version.py

@@ -17,6 +17,7 @@ This fixture is used to determine which version of Postgres to use for tests.
 class PgVersion(str, enum.Enum):
     V14 = "14"
     V15 = "15"
+    V16 = "16"
     # Instead of making version an optional parameter in methods, we can use this fake entry
     # to explicitly rely on the default server version (could be different from pg_version fixture value)
     NOT_SET = "<-POSTRGRES VERSION IS NOT SET->"

test_runner/regress/data/extension_test/5670669815/v16/ext_index.json

@@ -0,0 +1,7 @@
+{
+    "public_extensions": [],
+    "library_index": {
+        "TODO": "We still need PG16 extensions"
+    },
+    "extension_data": {}
+}

test_runner/regress/test_compatibility.py

@@ -20,7 +20,7 @@ from fixtures.pageserver.utils import (
     wait_for_last_record_lsn,
     wait_for_upload,
 )
-from fixtures.pg_version import PgVersion
+from fixtures.pg_version import PgVersion, skip_on_postgres
 from fixtures.port_distributor import PortDistributor
 from fixtures.remote_storage import LocalFsStorage, RemoteStorageKind, RemoteStorageUser
 from fixtures.types import Lsn
@@ -151,6 +151,7 @@ def test_create_snapshot(
     shutil.copytree(test_output_dir, compatibility_snapshot_dir)
 
 
+@skip_on_postgres(PgVersion.V16, reason="TODO: Enable after the first Postgres 16 release")
 @check_ondisk_data_compatibility_if_enabled
 @pytest.mark.xdist_group("compatibility")
 @pytest.mark.order(after="test_create_snapshot")
@@ -208,6 +209,7 @@ def test_backward_compatibility(
     ), "Breaking changes are allowed by ALLOW_BACKWARD_COMPATIBILITY_BREAKAGE, but the test has passed without any breakage"
 
 
+@skip_on_postgres(PgVersion.V16, reason="TODO: Enable after the first Postgres 16 release")
 @check_ondisk_data_compatibility_if_enabled
 @pytest.mark.xdist_group("compatibility")
 @pytest.mark.order(after="test_create_snapshot")

test_runner/regress/test_download_extensions.py

@@ -9,7 +9,7 @@ from fixtures.log_helper import log
 from fixtures.neon_fixtures import (
     NeonEnvBuilder,
 )
-from fixtures.pg_version import PgVersion
+from fixtures.pg_version import PgVersion, skip_on_postgres
 from fixtures.remote_storage import (
     RemoteStorageKind,
     S3Storage,
@@ -86,6 +86,7 @@ def upload_files(env):
 
 
 # Test downloading remote extension.
+@skip_on_postgres(PgVersion.V16, reason="TODO: PG16 extension building")
 @pytest.mark.parametrize("remote_storage_kind", available_s3_storages())
 @pytest.mark.skip(reason="https://github.com/neondatabase/neon/issues/4949")
 def test_remote_extensions(
@@ -148,6 +149,7 @@ def test_remote_extensions(
 
 
 # Test downloading remote library.
+@skip_on_postgres(PgVersion.V16, reason="TODO: PG16 extension building")
 @pytest.mark.parametrize("remote_storage_kind", available_s3_storages())
 @pytest.mark.skip(reason="https://github.com/neondatabase/neon/issues/4949")
 def test_remote_library(
@@ -206,6 +208,7 @@ def test_remote_library(
 #    RemoteStorageKind.REAL_S3 not in available_s3_storages(),
 #    reason="skipping test because real s3 not enabled",
 # )
+@skip_on_postgres(PgVersion.V16, reason="TODO: PG16 extension building")
 @pytest.mark.skip(reason="https://github.com/neondatabase/neon/issues/4949")
 def test_multiple_extensions_one_archive(
     neon_env_builder: NeonEnvBuilder,
@@ -251,7 +254,8 @@ def test_extension_download_after_restart(
     neon_env_builder: NeonEnvBuilder,
     pg_version: PgVersion,
 ):
-    if "15" in pg_version:  # SKIP v15 for now because test set only has extension built for v14
+    # TODO: PG15 + PG16 extension building
+    if "v14" not in pg_version:  # test set only has extension built for v14
         return None
 
     neon_env_builder.enable_extensions_remote_storage(RemoteStorageKind.MOCK_S3)