Merge pull request #9766 from matrix-org/rav/drop_py35

Require py36, Postgres 9.6, and sqlite 3.22

Author: richvdh

.buildkite/scripts/test_old_deps.sh

@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 
-# this script is run by buildkite in a plain `xenial` container; it installs the
+# this script is run by buildkite in a plain `bionic` container; it installs the
 # minimal requirements for tox and hands over to the py3-old tox environment.
 
 set -ex

changelog.d/9766.feature

@@ -0,0 +1 @@
+Synapse now requires Python 3.6 or later. It also requires Postgres 9.6 or later or SQLite 3.22 or later.

scripts-dev/build_debian_packages

@@ -18,11 +18,9 @@ import threading
 from concurrent.futures import ThreadPoolExecutor
 
 DISTS = (
-    "debian:stretch",
     "debian:buster",
     "debian:bullseye",
     "debian:sid",
-    "ubuntu:xenial",
     "ubuntu:bionic",
     "ubuntu:focal",
     "ubuntu:groovy",

setup.py

@@ -123,7 +123,7 @@ def exec_file(path_segments):
     zip_safe=False,
     long_description=long_description,
     long_description_content_type="text/x-rst",
-    python_requires="~=3.5",
+    python_requires="~=3.6",
     classifiers=[
         "Development Status :: 5 - Production/Stable",
         "Topic :: Communications :: Chat",

synapse/storage/database.py

@@ -2059,69 +2059,18 @@ def make_in_list_sql_clause(
 KV = TypeVar("KV")
 
 
-def make_tuple_comparison_clause(
-    database_engine: BaseDatabaseEngine, keys: List[Tuple[str, KV]]
-) -> Tuple[str, List[KV]]:
+def make_tuple_comparison_clause(keys: List[Tuple[str, KV]]) -> Tuple[str, List[KV]]:
     """Returns a tuple comparison SQL clause
 
-    Depending what the SQL engine supports, builds a SQL clause that looks like either
-    "(a, b) > (?, ?)", or "(a > ?) OR (a == ? AND b > ?)".
+    Builds a SQL clause that looks like "(a, b) > (?, ?)"
 
     Args:
-        database_engine
         keys: A set of (column, value) pairs to be compared.
 
     Returns:
         A tuple of SQL query and the args
     """
-    if database_engine.supports_tuple_comparison:
-        return (
-            "(%s) > (%s)" % (",".join(k[0] for k in keys), ",".join("?" for _ in keys)),
-            [k[1] for k in keys],
-        )
-
-    # we want to build a clause
-    #    (a > ?) OR
-    #    (a == ? AND b > ?) OR
-    #    (a == ? AND b == ? AND c > ?)
-    #    ...
-    #    (a == ? AND b == ? AND ... AND z > ?)
-    #
-    # or, equivalently:
-    #
-    #  (a > ? OR (a == ? AND
-    #    (b > ? OR (b == ? AND
-    #      ...
-    #        (y > ? OR (y == ? AND
-    #          z > ?
-    #        ))
-    #      ...
-    #    ))
-    #  ))
-    #
-    # which itself is equivalent to (and apparently easier for the query optimiser):
-    #
-    #  (a >= ? AND (a > ? OR
-    #    (b >= ? AND (b > ? OR
-    #      ...
-    #        (y >= ? AND (y > ? OR
-    #          z > ?
-    #        ))
-    #      ...
-    #    ))
-    #  ))
-    #
-    #
-
-    clause = ""
-    args = []  # type: List[KV]
-    for k, v in keys[:-1]:
-        clause = clause + "(%s >= ? AND (%s > ? OR " % (k, k)
-        args.extend([v, v])
-
-    (k, v) = keys[-1]
-    clause += "%s > ?" % (k,)
-    args.append(v)
-
-    clause += "))" * (len(keys) - 1)
-    return clause, args
+    return (
+        "(%s) > (%s)" % (",".join(k[0] for k in keys), ",".join("?" for _ in keys)),
+        [k[1] for k in keys],
+    )

synapse/storage/databases/main/client_ips.py

@@ -298,7 +298,6 @@ def _devices_last_seen_update_txn(txn):
             #      times, which is fine.
 
             where_clause, where_args = make_tuple_comparison_clause(
-                self.database_engine,
                 [("user_id", last_user_id), ("device_id", last_device_id)],
             )
 

synapse/storage/databases/main/devices.py

@@ -985,7 +985,7 @@ async def _remove_duplicate_outbound_pokes(self, progress, batch_size):
 
         def _txn(txn):
             clause, args = make_tuple_comparison_clause(
-                self.db_pool.engine, [(x, last_row[x]) for x in KEY_COLS]
+                [(x, last_row[x]) for x in KEY_COLS]
             )
             sql = """
                 SELECT stream_id, destination, user_id, device_id, MAX(ts) AS ts

synapse/storage/databases/main/events_bg_updates.py

@@ -838,7 +838,6 @@ def _calculate_chain_cover_txn(
         # We want to do a `(topological_ordering, stream_ordering) > (?,?)`
         # comparison, but that is not supported on older SQLite versions
         tuple_clause, tuple_args = make_tuple_comparison_clause(
-            self.database_engine,
             [
                 ("events.room_id", last_room_id),
                 ("topological_ordering", last_depth),

synapse/storage/engines/_base.py

@@ -42,14 +42,6 @@ def can_native_upsert(self) -> bool:
         """
         ...
 
-    @property
-    @abc.abstractmethod
-    def supports_tuple_comparison(self) -> bool:
-        """
-        Do we support comparing tuples, i.e. `(a, b) > (c, d)`?
-        """
-        ...
-
     @property
     @abc.abstractmethod
     def supports_using_any_list(self) -> bool:

synapse/storage/engines/postgres.py

@@ -47,8 +47,8 @@ def check_database(self, db_conn, allow_outdated_version: bool = False):
         self._version = db_conn.server_version
 
         # Are we on a supported PostgreSQL version?
-        if not allow_outdated_version and self._version < 90500:
-            raise RuntimeError("Synapse requires PostgreSQL 9.5+ or above.")
+        if not allow_outdated_version and self._version < 90600:
+            raise RuntimeError("Synapse requires PostgreSQL 9.6 or above.")
 
         with db_conn.cursor() as txn:
             txn.execute("SHOW SERVER_ENCODING")
@@ -129,13 +129,6 @@ def can_native_upsert(self):
         """
         return True
 
-    @property
-    def supports_tuple_comparison(self):
-        """
-        Do we support comparing tuples, i.e. `(a, b) > (c, d)`?
-        """
-        return True
-
     @property
     def supports_using_any_list(self):
         """Do we support using `a = ANY(?)` and passing a list"""