I am currently building a high traffic GIS system which uses python on the web front end. The system is 99% read only. In the interest of performance, I am considering using an externally generated cache of pre-generated read-optimised GIS information and storing in an SQLite database on each individual web server. In short it's going to be used as a distributed read-only cache which doesn't have to hop over the network. The back end OLTP store will be postgreSQL but that will handle less than 1% of the requests.
I have considered using Redis but the dataset is quite large and therefore it will push up the administrative cost and memory cost on the virtual machines this is being hosted on. Memcache is not suitable as it cannot do range queries.
Am I going to hit read-concurrency problems with SQLite doing this?
Is this a sensible approach?