Drop support for Postgres 10 in full text search code. (#14397)

4 files changed, 41 insertions, 95 deletions

diff --git a/changelog.d/14397.removal b/changelog.d/14397.removal
new file mode 100644
index 0000000000..e96b3de2bd
--- /dev/null
+++ b/changelog.d/14397.removal
@@ -0,0 +1 @@
+Remove support for PostgreSQL 10.
diff --git a/synapse/storage/databases/main/search.py b/synapse/storage/databases/main/search.py
index e9588d1755..3fe433f66c 100644
--- a/synapse/storage/databases/main/search.py
+++ b/synapse/storage/databases/main/search.py
@@ -463,18 +463,17 @@ class SearchStore(SearchBackgroundUpdateStore):
 
         if isinstance(self.database_engine, PostgresEngine):
             search_query = search_term
-            tsquery_func = self.database_engine.tsquery_func
-            sql = f"""
-            SELECT ts_rank_cd(vector, {tsquery_func}('english', ?)) AS rank,
+            sql = """
+            SELECT ts_rank_cd(vector, websearch_to_tsquery('english', ?)) AS rank,
             room_id, event_id
             FROM event_search
-            WHERE vector @@  {tsquery_func}('english', ?)
+            WHERE vector @@  websearch_to_tsquery('english', ?)
             """
             args = [search_query, search_query] + args
 
-            count_sql = f"""
+            count_sql = """
             SELECT room_id, count(*) as count FROM event_search
-            WHERE vector @@ {tsquery_func}('english', ?)
+            WHERE vector @@ websearch_to_tsquery('english', ?)
             """
             count_args = [search_query] + count_args
         elif isinstance(self.database_engine, Sqlite3Engine):
@@ -523,9 +522,7 @@ class SearchStore(SearchBackgroundUpdateStore):
 
         highlights = None
         if isinstance(self.database_engine, PostgresEngine):
-            highlights = await self._find_highlights_in_postgres(
-                search_query, events, tsquery_func
-            )
+            highlights = await self._find_highlights_in_postgres(search_query, events)
 
         count_sql += " GROUP BY room_id"
 
@@ -604,18 +601,17 @@ class SearchStore(SearchBackgroundUpdateStore):
 
         if isinstance(self.database_engine, PostgresEngine):
             search_query = search_term
-            tsquery_func = self.database_engine.tsquery_func
-            sql = f"""
-            SELECT ts_rank_cd(vector, {tsquery_func}('english', ?)) as rank,
+            sql = """
+            SELECT ts_rank_cd(vector, websearch_to_tsquery('english', ?)) as rank,
             origin_server_ts, stream_ordering, room_id, event_id
             FROM event_search
-            WHERE vector @@ {tsquery_func}('english', ?) AND
+            WHERE vector @@ websearch_to_tsquery('english', ?) AND
             """
             args = [search_query, search_query] + args
 
-            count_sql = f"""
+            count_sql = """
             SELECT room_id, count(*) as count FROM event_search
-            WHERE vector @@ {tsquery_func}('english', ?) AND
+            WHERE vector @@ websearch_to_tsquery('english', ?) AND
             """
             count_args = [search_query] + count_args
         elif isinstance(self.database_engine, Sqlite3Engine):
@@ -686,9 +682,7 @@ class SearchStore(SearchBackgroundUpdateStore):
 
         highlights = None
         if isinstance(self.database_engine, PostgresEngine):
-            highlights = await self._find_highlights_in_postgres(
-                search_query, events, tsquery_func
-            )
+            highlights = await self._find_highlights_in_postgres(search_query, events)
 
         count_sql += " GROUP BY room_id"
 
@@ -714,7 +708,7 @@ class SearchStore(SearchBackgroundUpdateStore):
         }
 
     async def _find_highlights_in_postgres(
-        self, search_query: str, events: List[EventBase], tsquery_func: str
+        self, search_query: str, events: List[EventBase]
     ) -> Set[str]:
         """Given a list of events and a search term, return a list of words
         that match from the content of the event.
@@ -725,7 +719,6 @@ class SearchStore(SearchBackgroundUpdateStore):
         Args:
             search_query
             events: A list of events
-            tsquery_func: The tsquery_* function to use when making queries
 
         Returns:
             A set of strings.
@@ -758,13 +751,16 @@ class SearchStore(SearchBackgroundUpdateStore):
                 while stop_sel in value:
                     stop_sel += ">"
 
-                query = f"SELECT ts_headline(?, {tsquery_func}('english', ?), %s)" % (
-                    _to_postgres_options(
-                        {
-                            "StartSel": start_sel,
-                            "StopSel": stop_sel,
-                            "MaxFragments": "50",
-                        }
+                query = (
+                    "SELECT ts_headline(?, websearch_to_tsquery('english', ?), %s)"
+                    % (
+                        _to_postgres_options(
+                            {
+                                "StartSel": start_sel,
+                                "StopSel": stop_sel,
+                                "MaxFragments": "50",
+                            }
+                        )
                     )
                 )
                 txn.execute(query, (value, search_query))
diff --git a/synapse/storage/engines/postgres.py b/synapse/storage/engines/postgres.py
index 0c4fd88914..719a517336 100644
--- a/synapse/storage/engines/postgres.py
+++ b/synapse/storage/engines/postgres.py
@@ -170,22 +170,6 @@ class PostgresEngine(
         """Do we support the `RETURNING` clause in insert/update/delete?"""
         return True
 
-    @property
-    def tsquery_func(self) -> str:
-        """
-        Selects a tsquery_* func to use.
-
-        Ref: https://www.postgresql.org/docs/current/textsearch-controls.html
-
-        Returns:
-            The function name.
-        """
-        # Postgres 11 added support for websearch_to_tsquery.
-        assert self._version is not None
-        if self._version >= 110000:
-            return "websearch_to_tsquery"
-        return "plainto_tsquery"
-
     def is_deadlock(self, error: Exception) -> bool:
         if isinstance(error, psycopg2.DatabaseError):
             # https://www.postgresql.org/docs/current/static/errcodes-appendix.html
diff --git a/tests/storage/test_room_search.py b/tests/storage/test_room_search.py
index 868b5bee84..ef850daa73 100644
--- a/tests/storage/test_room_search.py
+++ b/tests/storage/test_room_search.py
@@ -12,9 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from typing import List, Tuple, Union
+from typing import List, Tuple
 from unittest.case import SkipTest
-from unittest.mock import PropertyMock, patch
 
 from twisted.test.proto_helpers import MemoryReactor
 
@@ -220,10 +219,8 @@ class MessageSearchTest(HomeserverTestCase):
 
     PHRASE = "the quick brown fox jumps over the lazy dog"
 
-    # Each entry is a search query, followed by either a boolean of whether it is
-    # in the phrase OR a tuple of booleans: whether it matches using websearch
-    # and using plain search.
-    COMMON_CASES: List[Tuple[str, Union[bool, Tuple[bool, bool]]]] = [
+    # Each entry is a search query, followed by a boolean of whether it is in the phrase.
+    COMMON_CASES = [
         ("nope", False),
         ("brown", True),
         ("quick brown", True),
@@ -231,13 +228,13 @@ class MessageSearchTest(HomeserverTestCase):
         ("quick \t brown", True),
         ("jump", True),
         ("brown nope", False),
-        ('"brown quick"', (False, True)),
+        ('"brown quick"', False),
         ('"jumps over"', True),
-        ('"quick fox"', (False, True)),
+        ('"quick fox"', False),
         ("nope OR doublenope", False),
-        ("furphy OR fox", (True, False)),
-        ("fox -nope", (True, False)),
-        ("fox -brown", (False, True)),
+        ("furphy OR fox", True),
+        ("fox -nope", True),
+        ("fox -brown", False),
         ('"fox" quick', True),
         ('"quick brown', True),
         ('" quick "', True),
@@ -246,11 +243,11 @@ class MessageSearchTest(HomeserverTestCase):
     # TODO Test non-ASCII cases.
 
     # Case that fail on SQLite.
-    POSTGRES_CASES: List[Tuple[str, Union[bool, Tuple[bool, bool]]]] = [
+    POSTGRES_CASES = [
         # SQLite treats NOT as a binary operator.
-        ("- fox", (False, True)),
-        ("- nope", (True, False)),
-        ('"-fox quick', (False, True)),
+        ("- fox", False),
+        ("- nope", True),
+        ('"-fox quick', False),
         # PostgreSQL skips stop words.
         ('"the quick brown"', True),
         ('"over lazy"', True),
@@ -275,7 +272,7 @@ class MessageSearchTest(HomeserverTestCase):
         if isinstance(main_store.database_engine, PostgresEngine):
             assert main_store.database_engine._version is not None
             found = main_store.database_engine._version < 140000
-        self.COMMON_CASES.append(('"fox quick', (found, True)))
+        self.COMMON_CASES.append(('"fox quick', found))
 
     def test_tokenize_query(self) -> None:
         """Test the custom logic to tokenize a user's query."""
@@ -315,16 +312,10 @@ class MessageSearchTest(HomeserverTestCase):
             )
 
     def _check_test_cases(
-        self,
-        store: DataStore,
-        cases: List[Tuple[str, Union[bool, Tuple[bool, bool]]]],
-        index=0,
+        self, store: DataStore, cases: List[Tuple[str, bool]]
     ) -> None:
         # Run all the test cases versus search_msgs
         for query, expect_to_contain in cases:
-            if isinstance(expect_to_contain, tuple):
-                expect_to_contain = expect_to_contain[index]
-
             result = self.get_success(
                 store.search_msgs([self.room_id], query, ["content.body"])
             )
@@ -343,9 +334,6 @@ class MessageSearchTest(HomeserverTestCase):
 
         # Run them again versus search_rooms
         for query, expect_to_contain in cases:
-            if isinstance(expect_to_contain, tuple):
-                expect_to_contain = expect_to_contain[index]
-
             result = self.get_success(
                 store.search_rooms([self.room_id], query, ["content.body"], 10)
             )
@@ -366,38 +354,15 @@ class MessageSearchTest(HomeserverTestCase):
         """
         Test searching for phrases using typical web search syntax, as per postgres' websearch_to_tsquery.
         This test is skipped unless the postgres instance supports websearch_to_tsquery.
-        """
-
-        store = self.hs.get_datastores().main
-        if not isinstance(store.database_engine, PostgresEngine):
-            raise SkipTest("Test only applies when postgres is used as the database")
-
-        if store.database_engine.tsquery_func != "websearch_to_tsquery":
-            raise SkipTest(
-                "Test only applies when postgres supporting websearch_to_tsquery is used as the database"
-            )
 
-        self._check_test_cases(store, self.COMMON_CASES + self.POSTGRES_CASES, index=0)
-
-    def test_postgres_non_web_search_for_phrase(self):
-        """
-        Test postgres searching for phrases without using web search, which is used when websearch_to_tsquery isn't
-        supported by the current postgres version.
+        See https://www.postgresql.org/docs/current/textsearch-controls.html
         """
 
         store = self.hs.get_datastores().main
         if not isinstance(store.database_engine, PostgresEngine):
             raise SkipTest("Test only applies when postgres is used as the database")
 
-        # Patch supports_websearch_to_tsquery to always return False to ensure we're testing the plainto_tsquery path.
-        with patch(
-            "synapse.storage.engines.postgres.PostgresEngine.tsquery_func",
-            new_callable=PropertyMock,
-        ) as supports_websearch_to_tsquery:
-            supports_websearch_to_tsquery.return_value = "plainto_tsquery"
-            self._check_test_cases(
-                store, self.COMMON_CASES + self.POSTGRES_CASES, index=1
-            )
+        self._check_test_cases(store, self.COMMON_CASES + self.POSTGRES_CASES)
 
     def test_sqlite_search(self):
         """
@@ -407,4 +372,4 @@ class MessageSearchTest(HomeserverTestCase):
         if not isinstance(store.database_engine, Sqlite3Engine):
             raise SkipTest("Test only applies when sqlite is used as the database")
 
-        self._check_test_cases(store, self.COMMON_CASES, index=0)
+        self._check_test_cases(store, self.COMMON_CASES)