On Mar 18, 2011, at 11:19 AM, Sebastian Elsner wrote: > Hello, > > I wanted to make sure, I get this right: every session creates its own > connection on demand (only if I actually do query with the session), right?
right > So, using MySQL with max_connections = 100 I quickly run out of connections, > because every client is using about 6 connections, one for each dialog > window, which has its own session instance. seems like an architecture that could use some trimming.... > > Now I am playing with poolclass = StaticPool instead of QueuePool, which > seems to give me the the same speed per query. Or is there any difference to > expect, which I just haven't encountered? Only the enormous difference that MySQL connections aren't threadsafe, as well as the fact that each Session runs its own transaction, a pattern that cannot be shared by multiple sessions on one connection. Though MySQL in MyISAM mode renders the latter point to be moot. > Also, is there something about StaticPool which prohibits me to do certain > things a QueuePool could (except the reconnection note in the docs)? I guess > having multiple threads with their own session querying would not work?! The timeout thing is pretty key with MySQL since their client lib times out a connection unused for 8 hours (such as, overnight). QueuePool has a "threadlocal" flag that returns the same connection in the same thread (on create_engine() its via use_threadlocal=True, and it appears that flag didn't make it into the docs) that may be able to help here. > > Thank you, > > Sebastian > > -- > You received this message because you are subscribed to the Google Groups > "sqlalchemy" group. > To post to this group, send email to sqlalchemy@googlegroups.com. > To unsubscribe from this group, send email to > sqlalchemy+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/sqlalchemy?hl=en. > -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
