Revert "Unified search query syntax using the full-text search capabilities of the underlying DB. (#11635)"

This reverts commit d902181de98399d90c46c4e4e2cf631064757941.

1 files changed, 0 insertions, 16 deletions

diff --git a/synapse/storage/engines/postgres.py b/synapse/storage/engines/postgres.py
index 9bf74bbf59..d8c0f64d9a 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