diff options
Diffstat (limited to 'lib/sqlalchemy/engine/default.py')
| -rw-r--r-- | lib/sqlalchemy/engine/default.py | 21 |
1 files changed, 17 insertions, 4 deletions
diff --git a/lib/sqlalchemy/engine/default.py b/lib/sqlalchemy/engine/default.py index 9574e9980..e91e34f00 100644 --- a/lib/sqlalchemy/engine/default.py +++ b/lib/sqlalchemy/engine/default.py @@ -321,10 +321,23 @@ class DefaultDialect(interfaces.Dialect): @util.memoized_property def _supports_statement_cache(self): - return ( - self.__class__.__dict__.get("supports_statement_cache", False) - is True - ) + ssc = self.__class__.__dict__.get("supports_statement_cache", None) + if ssc is None: + util.warn( + "Dialect %s:%s will not make use of SQL compilation caching " + "as it does not set the 'supports_statement_cache' attribute " + "to ``True``. This can have " + "significant performance implications including some " + "performance degradations in comparison to prior SQLAlchemy " + "versions. Dialect maintainers should seek to set this " + "attribute to True after appropriate development and testing " + "for SQLAlchemy 1.4 caching support. Alternatively, this " + "attribute may be set to False which will disable this " + "warning." % (self.name, self.driver), + code="cprf", + ) + + return bool(ssc) @util.memoized_property def _type_memos(self): |