part of Pylons controller:
"""
def index(self):
query = Session(FGM).filter(FGM.c.state == 'normal')
...
query = query.filter(FGM.c.anotherstate.in_('read', 'write'))
...
ids = getIds()
...
query = query.filter(FGM.c.type.in_(ids))
"""
query executed against eight shards, and the one query against master
base
some profiling:
580971 function calls (579337 primitive calls) in 3.088 CPU
seconds
Ordered by: internal time
List reduced from 1045 to 30 due to restriction <30>
ncalls tottime percall cumtime percall
filename:lineno(function)
14 0.399 0.028 0.399 0.028 {method 'recv' of
'_socket.socket' objects}
12040 0.218 0.000 1.246 0.000 /var/lib/python-support/
python2.5/sqlalchemy/orm/mapper.py:1280(_instance)
11 0.181 0.016 0.181 0.016 {method 'query' of
'_mysql.connection' objects}
55745 0.179 0.000 0.303 0.000 /var/lib/python-support/
python2.5/sqlalchemy/engine/base.py:1340(__getitem__)
6543 0.136 0.000 0.447 0.000 /var/lib/python-support/
python2.5/sqlalchemy/orm/mapper.py:1412(populate_instance)
12040 0.130 0.000 0.369 0.000 /var/lib/python-support/
python2.5/sqlalchemy/orm/mapper.py:851(identity_key_from_row)
55745 0.123 0.000 0.124 0.000 /var/lib/python-support/
python2.5/sqlalchemy/engine/base.py:1590(_get_col)
12051 0.098 0.000 1.707 0.000 /var/lib/python-support/
python2.5/sqlalchemy/orm/query.py:850(iterate_instances)
19667 0.097 0.000 0.301 0.000 /var/lib/python-support/
python2.5/sqlalchemy/orm/query.py:1465(exec_with_path)
19633 0.090 0.000 0.203 0.000 /var/lib/python-support/
python2.5/sqlalchemy/orm/strategies.py:76(new_execute)
12040 0.078 0.000 0.188 0.000 /var/lib/python-support/
python2.5/sqlalchemy/util.py:904(append)
6543 0.061 0.000 0.061 0.000 /var/lib/python-support/
python2.5/sqlalchemy/orm/attributes.py:675(__init__)
18048 0.059 0.000 0.090 0.000 /var/lib/python-support/
python2.5/sqlalchemy/orm/attributes.py:41(__get__)
12040 0.058 0.000 1.304 0.000 /var/lib/python-support/
python2.5/sqlalchemy/orm/query.py:868(main)
12040 0.056 0.000 0.056 0.000 /var/lib/python-support/
python2.5/sqlalchemy/orm/attributes.py:898(__contains__)
1 0.050 0.050 3.044 3.044 /home/stromnov/......./
controllers/controller.py:113(index)
And I just want to optimize this to something like this:
_query = Query(FGM).filter(.......)
def index(self):
ids = getIds()
...
query = _query.filter(FGM.c.type.in_(ids))
execute_query_using_session(query=query, session=Session)
On 7 мар, 18:49, Michael Bayer <[EMAIL PROTECTED]> wrote:
> On Mar 7, 2008, at 6:11 AM, Andrew Stromnov wrote:
>
>
>
> > I have only two complicated queries with in_() statements in my app
> > (under Pylons). How to pregenerate common parts of this queries and
> > assign Session (in my case ShardedSession) to them at runtime?
>
> this is a vague question. it depends on what effort you are looking
> to minimize. If it were my app, and I was sick of typing a big long
> query each time, I'd just build a helper function q =
> generate_long_query(session) that does it for me. Alternatively you
> can build up a Query object and reuse it, although a Query is attached
> to a single session; we'd have to give you a method
> q.with_session(somesession) to reassign a pre-built query with a
> different session...but that doesn't seem very different from just
> building your own function.
>
> If you're building a full select() statement, just build it somewhere,
> then just use it as needed....query.from_statement(myselect).
>
> If I read your question completely literally, it seems like you'd like
> the session to use a certain query "automatically", I don't exactly
> understand that since the Session doesn't generate SQL queries.
>
> if its the "performance" of compiling a query you're concerned about,
> I think query compilation performance is fairly negligible - I think
> you should run some profiling to determine if that's actually a
> bottleneck. even in that case i think query.from_statement() can
> accept a Compiled object (or if not we can make that work).
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