On Wed, Nov 22, 2017 at 10:56 AM, mdob <mike.dobrzan...@gmail.com> wrote: > Hi SQLAlchemy Group, > > I've been experimenting with automap (in SQLAlchemy 1.0.20) a bit and I > wonder how safe is to automap multiple databases in threads because I run > into random errors of classes not being mapped: > > One or more mappers failed to initialize - can't proceed with initialization > of other mappers. Original exception was: Class > 'sqlalchemy.ext.automap.Manufacturer' is not mapped > > I was a bit surprised the class was added to automap module which could > cause conflicts when automapping databases simultaneously in threads. Is > this intentional that the automapped class is added to automap module or I > messed something up?
are you using individual bases and metadata collections? this should be OK in theory, however mappers are subject to a global registry as well as the global configure_mappers() step - this routine is mutexed for thread-safe operation. > > I was digging in sqlalchem/ext/automap.py and I found that a class method > AutomapBase.prepare uses class > sqlalchemy.ext.declarative.base._DeferredMapperConfig to store configs. This > class would be shared between threads. Is it possible one thread flashes > configs and other breaks automap process on other thread? shouldn't. > > I can't reproduce the problem when secluding automap from my application so > it's hard to give code example. I'm sorry that question is not very precise > but maybe you could give me any hint where to look? stack trace would help > > Kind regards, > Michal > > > -- > SQLAlchemy - > The Python SQL Toolkit and Object Relational Mapper > > http://www.sqlalchemy.org/ > > To post example code, please provide an MCVE: Minimal, Complete, and > Verifiable Example. See http://stackoverflow.com/help/mcve for a full > description. > --- > You received this message because you are subscribed to the Google Groups > "sqlalchemy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sqlalchemy+unsubscr...@googlegroups.com. > To post to this group, send email to sqlalchemy@googlegroups.com. > Visit this group at https://groups.google.com/group/sqlalchemy. > For more options, visit https://groups.google.com/d/optout. -- SQLAlchemy - The Python SQL Toolkit and Object Relational Mapper http://www.sqlalchemy.org/ To post example code, please provide an MCVE: Minimal, Complete, and Verifiable Example. See http://stackoverflow.com/help/mcve for a full description. --- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at https://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
