we're also assuming that you've exhausted these approaches (which would be a lot more appropriate for this sort of thing):
http://forge.mysql.com/wiki/MySQL_Proxy http://dev.mysql.com/doc/refman/5.0/en/replication.html On Jun 9, 2008, at 2:22 PM, qhfgva wrote: > > > > On Jun 6, 12:34 pm, Michael Bayer <[EMAIL PROTECTED]> wrote: >> On Jun 6, 2008, at 2:29 PM, qhfgva wrote: >> >> >> >> >> >>> We have (what I think of as) a moderately complicated database >>> configuration and I'm hoping there will be a way to configure >>> sqlalchemy to deal with it. The basic scenario is like this: >> >>> There are N mysql servers in different geographical regions that are >>> all replicating against one master. In the interest of speed the >>> rule >>> in each location is to do reads which are very frequent against the >>> local copy of the database and if there is a write to do that >>> against >>> the master. As an added wrinkle the user has an option to write to >>> the master with a master_pos_wait so that the current process will >>> wait until replication has caught up with the update just executed. >>> Hopefully that makes sense and gives enough of a flavor of what I've >>> got in mind. >> >>> I'm pretty new to sqlalchemy. Is the above feasible? If so are >>> there >>> examples to compare with and learn from doing something similar? >>> Where (api/code) would I start looking to accomplish the above? >> >>> Any tips to get me going would be much appreciated. >> >> easiest approach is to use multiple sessions, multiple engines. >> Your >> app would need to know which engine it wants to talk to, and binds a >> session to that engine. Binding is described here: >> http://www.sqlalchemy.org/docs/04/session.html#unitofwork_getting_bin >> ... > > Thanks I'll take a look. I left out what I think is an important part > of this scenario (or maybe it's trivial - I don't have a good > perspective on this yet). In any case, I would like to use the ORM > component of sqlalchemy and completely hide the fact that the read/ > write connections are possibly different. (They might become the > same connection if the local database becomes unaccessible and/or is > too far behind the master). > > In other words I'd like to have a handle to, say, a user object, and > do reads/updates to it with the programmer using this object not > caring about how the work gets done. So for instance I select a > number of user objects that come from the local database. Later I > update a field on one of these and the update takes place on the > master directly. > > Is that weird? Doable? Unfortunately this is the environment I need > to get this working with. > > As a side note, we manage this difference by hand now, it's really > annoying which is why I'd love to abstract it away. > > thanks. > > --~--~---------~--~----~------------~-------~--~----~ 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 [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~----------~----~----~----~------~----~------~--~---
