Currently when sqlalchemy performs a polymorphic lookup, it queries against all the detail tables, and returns the correct Python object represented by the polymorphic identity. Essentially you get a sub select for each detail table that is included in your primary join even though only one of the detail tables contains the data that is specific to the identity of the object. Is there currently a way, or a plan to support, splitting the polymorphic query into two queries? The first would get the base table, the second would retrieve the details based on the discovered table. This way only two tables would be queried instead of n where n is the number of polymorphic identities.
Our DBAs have concerns that as our tables grow, possibly to the size of 2.5million rows, that unioning against multiple tables, despite the fact that we are unioning against a primary key, will become non- performant. I know I could write a custom mapper to resolve this issue, however, I thought I would bring this up since it may affect other users, and there may already be a way to solve this easily of which I am not aware. --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
