You probably need to hit that flag early before anything connects. A safe
place would be in the dbapi() accessor itself, or in the __init__ method of the
dialect class.
Sent from my iPhone
> On Oct 24, 2014, at 1:32 PM, Lycovian <mfwil...@gmail.com> wrote:
>
> Thanks for the reply Mike. I've been tracking SQLAlchemy for years now and
> it's probably some of the best code, docs, and support I've ever seen.
>
> Yes, I have verified that pyodbc and the pooling flag work:
> In [1]: import pyodbc
> In [2]: pyodbc.pooling = False
> In [3]: conn = pyodbc.connect
> pyodbc.connect
> In [3]: conn = pyodbc.connect('DSN=tdprod')
> In [4]: conn.execute('select current_timestamp').fetchall()
> Out[4]: [(datetime.datetime(2014, 10, 24, 9, 22, 34, 270000), )]
> In [5]: pyodbc.pooling = True
> In [6]: conn.execute('select current_timestamp').fetchall()
> Out[6]: [(datetime.datetime(2014, 10, 24, 9, 22, 46, 500000), )]
>
> Without pooling (and with core dump):
> In [1]: import pyodbc
> In [2]: conn = pyodbc.connect('DSN=tdprod')
> Fatal Python error: Unable to set SQL_ATTR_CONNECTION_POOLING attribute.
> Aborted (core dumped)
>
>
> Since a "generic" pyodbc connection is out, can you comment on how I could
> set the pyodbc.pooling flag as part of a dialect? To get me off the ground
> please see below for my bootstrap base.py and pyodbc.py for a Teradata
> dialect that could use pyodbc. I have been unable to set pyodbc.pooling
> appropriately. Feel free to comment additionally on the best way to create a
> minimal functional dialect that would pass a basic test harness.
>
> <base.py>
> import operator
> import re
>
> from sqlalchemy.sql import compiler, expression, text, bindparam
> from sqlalchemy.engine import default, base, reflection
> from sqlalchemy import types as sqltypes
> from sqlalchemy.sql import operators as sql_operators
> from sqlalchemy import schema as sa_schema
> from sqlalchemy import util, sql, exc
>
> from sqlalchemy.types import CHAR, VARCHAR, TIME, NCHAR, NVARCHAR,\
> TEXT, DATE, DATETIME, FLOAT, NUMERIC,\
> BIGINT, INT, INTEGER, SMALLINT, BINARY,\
> VARBINARY, DECIMAL, TIMESTAMP, Unicode,\
> UnicodeText, REAL
>
> RESERVED_WORDS = set([])
>
> class TeradataTypeCompiler(compiler.GenericTypeCompiler):
> pass
>
> class TeradataInspector(reflection.Inspector):
> pass
>
> class TeradataExecutionContext(default.DefaultExecutionContext):
> pass
>
> class TeradataSQLCompiler(compiler.SQLCompiler):
> pass
>
> class TeradataDDLCompiler(compiler.DDLCompiler):
> pass
>
> class TeradataIdentifierPreparer(compiler.IdentifierPreparer):
> reserved_words = RESERVED_WORDS
>
> class TeradataDialect(default.DefaultDialect):
> pass
> </base.py>
>
> <pyodbc.py>
> import pyodbc
>
> from .base import TeradataDialect, TeradataExecutionContext
> from sqlalchemy.connectors.pyodbc import PyODBCConnector
>
> pyodbc.pooling = False
>
> class TeradataExecutionContext_pyodbc(TeradataExecutionContext):
> pass
>
> class TeradataDialect_pyodbc(PyODBCConnector, TeradataDialect):
> execution_ctx_cls = TeradataExecutionContext_pyodbc
>
> pyodbc_driver_name = 'Teradata'
>
> def initialize(self, connection):
>
> # Teradata requires pooling off for pyodbc
> super(TeradataDialect_pyodbc, self).initialize(connection)
> self.dbapi.pooling = False
>
> dialect = TeradataDialect_pyodbc
> </pyodbc.py>
>
> If there is any way to make this simpler please let me know, but in
> particular for this very simple dialect I need to be able to set the
> pyodbc.pooling attribute to False.
>
>
>
>> On Thursday, October 23, 2014 9:38:30 PM UTC-7, Michael Bayer wrote:
>>
>>> On Oct 23, 2014, at 2:50 PM, Lycovian <mfwi...@gmail.com> wrote:
>>>
>>> Is there a way to use a pyodbc connection without a dialect?
>>
>> there is not. the dialect is responsible for formulating SQL of the format
>> that the database understands as well as dealing with idiosyncrasies of the
>> DBAPI driver (of which pyodbc has many, many, many, which are also specific
>> to certain databases).
>>
>>
>>>
>>> Barring that working which seems unlikely since I can't find any working
>>> examples, I have started stubbing out a very simple Teradata dialect but I
>>> can't figure out how to manually set pyodbc.pooling = False. This is
>>> required as the TD ODBC driver will core dump on connect if this isn't set.
>>> I've tried the following in the my pyodbc.py my dialect but on testing it
>>> core dumps indicating the value isn't being set.
>>>
>>> Here is the pyodbc.py for my TD dialect. I'm trying to control pooling in
>>> two different ways in this example but neither works:
>>
>>
>>
>>
>> have you tried talking to your database using just pyodbc directly? does
>> this flag even work ?
>
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