diff options
Diffstat (limited to 'lib/sqlalchemy/dialects/postgresql/asyncpg.py')
| -rw-r--r-- | lib/sqlalchemy/dialects/postgresql/asyncpg.py | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/lib/sqlalchemy/dialects/postgresql/asyncpg.py b/lib/sqlalchemy/dialects/postgresql/asyncpg.py index 7dbcfa357..4c3c47ba6 100644 --- a/lib/sqlalchemy/dialects/postgresql/asyncpg.py +++ b/lib/sqlalchemy/dialects/postgresql/asyncpg.py @@ -96,6 +96,25 @@ To disable the prepared statement cache, use a value of zero:: stale, nor can it retry the statement as the PostgreSQL transaction is invalidated when these errors occur. +Disabling the PostgreSQL JIT to improve ENUM datatype handling +--------------------------------------------------------------- + +Asyncpg has an `issue <https://github.com/MagicStack/asyncpg/issues/727>`_ when +using PostgreSQL ENUM datatypes, where upon the creation of new database +connections, an expensive query may be emitted in order to retrieve metadata +regarding custom types which has been shown to negatively affect performance. +To mitigate this issue, the PostgreSQL "jit" setting may be disabled from the +client using this setting passed to :func:`_asyncio.create_async_engine`:: + + engine = create_async_engine( + "postgresql+asyncpg://user:password@localhost/tmp", + connect_args={"server_settings": {"jit": "off"}}, + ) + +.. seealso:: + + https://github.com/MagicStack/asyncpg/issues/727 + """ # noqa import collections |