[Sqlalchemy-tickets] Issue #4158: pyodbc SQL Server cursor.fast_executemany (zzzeek/sqlalchemy)

[Danny H. <iss...@bi...>]

New issue 4158: pyodbc SQL Server cursor.fast_executemany
https://bitbucket.org/zzzeek/sqlalchemy/issues/4158/pyodbc-sql-server-cursorfast_executemany

Danny Hollandmoritz:

Hi,

pyodbc implemented a different execute_many handling for native Microsoft ODBC drivers, which greatly speeds up bulk inserts. (https://github.com/mkleehammer/pyodbc/issues/120)

To use it, "fast_executemany" needs to be set to True on the pyodbc cursor instance.

At the moment sqlalchemy does not use this flag.

To be able to use this feature with sqlalchemy, i changed dialects.mssql.pyodbc.MSExecutionContext_pyodbc to:


```
#!python

class MSExecutionContext_pyodbc(MSExecutionContext):
    _embedded_scope_identity = False

    def create_cursor(self):
        if self._use_server_side_cursor():
            self._is_server_side = True
            return self.create_server_side_cursor()
        else:
            self._is_server_side = False
            cursor = self._dbapi_connection.cursor()
            cursor.fast_executemany = True
            return cursor


    def pre_exec(self):
        """where appropriate, issue "select scope_identity()" in the same
        statement.

```

But i am sure, there is a better solution for this. (e.g. as a connection string parameter when initiating a sqlalchemy engine)

Would it be possible to implement the usage of pyodbc's fast_executemany natively for the pyodbc mssql dialect?

Greetings
Danny