Hello,
I think I have found a bug, but I may be doing something wrong. It
looks like session.query(<class>).set_shard(<shard_id>) does not work
and session.connection(shard_id=<shard_id>).execute does. The first
does not return any result, the second one does (even when executing
the same query).
I've tested it with MySQL 3.23.54 and 5.0.45 and sqlalchemy 0.5.0rc1,
rc2 and rc4.
Here is the test database setup:
CREATE TABLE persons (
id INTEGER NOT NULL AUTO_INCREMENT,
name VARCHAR(20) NOT NULL,
PRIMARY KEY (id),
UNIQUE (name)
);
insert into persons (name) values('bob');
insert into persons (name) values('alice');
Here is the test code:
#!/opt/python-2.4/bin/python
import sys
import logging
import sqlalchemy as sa
from sqlalchemy.orm.shard import ShardedSession
from sqlalchemy.orm import sessionmaker
from sqlalchemy.ext.declarative import declarative_base
logging.basicConfig(stream=sys.stdout, format='%(asctime)s %(levelname)
s %(name)s: %(message)s')
logging.getLogger('sqlalchemy').setLevel(logging.DEBUG)
logging.getLogger().setLevel(logging.DEBUG)
Session = sessionmaker(class_=ShardedSession)
Base = declarative_base()
class Person(Base):
__tablename__ = 'persons'
id = sa.Column(sa.Integer, primary_key=True)
name = sa.Column(sa.String(20), unique=True, nullable=False)
def __str__(self):
return '<Person(%s, %s)>' % (self.id, self.name)
def shard_chooser(mapper, instance, clause=None):
raise NotImplementedError
def id_chooser(query, ident):
raise NotImplementedError
def query_chooser(query):
raise NotImplementedError
Session.configure(shard_chooser=shard_chooser,
id_chooser=id_chooser,
query_chooser=query_chooser)
session = Session()
shard_id='test'
engine = sa.create_engine('mysql://[EMAIL PROTECTED]/%s' % shard_id)
session.bind_shard(shard_id, engine)
q = session.query(Person).set_shard(shard_id).limit(1)
logging.debug("QUERY 1: %s", q)
rows = list(q.all())
logging.debug("QUERY 1 RESULT: %s" % rows)
#
# now to it manually:
#
q = '''SELECT persons.id AS persons_id, persons.name AS persons_name
FROM persons
LIMIT 1
'''
logging.debug("QUERY 2: %s", q)
rows = session.connection(shard_id=shard_id).execute(q)
rows = list(rows)
logging.debug("QUERY 2: RESULT: %s" % rows)
And here is the code output:
2008-11-26 10:52:26,043 INFO sqlalchemy.orm.strategies.ColumnLoader:
Person.id register managed attribute
2008-11-26 10:52:26,044 INFO sqlalchemy.orm.strategies.ColumnLoader:
Person.name register managed attribute
2008-11-26 10:52:26,045 DEBUG root: QUERY 1: SELECT persons.id AS
persons_id, persons.name AS persons_name
FROM persons
LIMIT 1
2008-11-26 10:52:26,061 INFO sqlalchemy.pool.QueuePool.0x...8bf4:
Created new connection <_mysql.connection open to 'localhost' at
82b02ec>
2008-11-26 10:52:26,062 INFO sqlalchemy.pool.QueuePool.0x...8bf4:
Connection <_mysql.connection open to 'localhost' at 82b02ec> checked
out from pool
2008-11-26 10:52:26,062 INFO sqlalchemy.engine.base.Engine.0x...8a14:
BEGIN
2008-11-26 10:52:26,060 INFO sqlalchemy.engine.base.Engine.0x...8a14:
SELECT persons.id AS persons_id, persons.name AS persons_name
FROM persons
LIMIT 1
2008-11-26 10:52:26,064 INFO sqlalchemy.engine.base.Engine.0x...8a14:
[]
2008-11-26 10:52:26,066 DEBUG sqlalchemy.engine.base.Engine.0x...8a14:
Col ('persons_id', 'persons_name')
2008-11-26 10:52:26,070 DEBUG root: QUERY 1 RESULT: []
2008-11-26 10:52:26,070 DEBUG root: QUERY 2: SELECT persons.id AS
persons_id, persons.name AS persons_name
FROM persons
LIMIT 1
2008-11-26 10:52:26,071 INFO sqlalchemy.engine.base.Engine.0x...8a14:
SELECT persons.id AS persons_id, persons.name AS persons_name
FROM persons
LIMIT 1
2008-11-26 10:52:26,071 INFO sqlalchemy.engine.base.Engine.0x...8a14:
{}
2008-11-26 10:52:26,073 DEBUG sqlalchemy.engine.base.Engine.0x...8a14:
Col ('persons_id', 'persons_name')
2008-11-26 10:52:26,073 DEBUG sqlalchemy.engine.base.Engine.0x...8a14:
Row (1L, 'bob')
2008-11-26 10:52:26,074 DEBUG root: QUERY 2: RESULT: [(1L, 'bob')]
There are two things I notice in the sqlalchemy.Engine logs; the
second SELECT statement seems to have an additional newline and the
next log (which seem to be the parameters for the select statement)
contain a {} instead of a [].
Am I doing something wrong here or is this supposed to work?
Regards,
Ids
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