Hi, I'm currently running several python applications (each app using sqlalchemy) accessing (read/write) a single SQLite database stored on disk. For performance reasons, I would like to store this db file in RAM memory (ie, in my /dev/shm) The applications would then access a shared in-memory db through SQLAlchemy and a backup application would periodically make a hot copy of the in-memory db to disk. Then, on a [power off, power on] sequence, this backup app would copy the backed up db file from disk to RAM before launching the other apps. Before starting, I would like to know if you think it is feaseable. My questions are: 1- Has SQLALchemy an API to do a hot copy? (based on <http://sqlite.org/backup.html> http://sqlite.org/backup.html for this particular db type) 2- If so, is this an actual hot copy, ie: the other apps will still run without waiting for the backup app to finish he backup? 3- Is there a particular configuration in SQLAlchemy that enables sharing an in-momory db from different apps (python processes)? Thanks a lot for your feedback, Pierre --
Pierre, While I do think this is feasible, I would discourage going down this path unless you have a really good reason. It sounds like you need a real database engine like postgres here. It basically does everything you describe out of the box, is easy to set up, and will likely be more reliable than anything you could come up with on your own. It will also perform better when dealing with many simultaneous transactions. If you still run into performance problems you could look into introducing a caching layer such as memcached, but I wouldn't cross that bridge until I had thoroughly tweaked my db settings and identified real bottlenecks in my application(s). Jeff Peck -- 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/groups/opt_out.
