Disclaimer - views expressed in this blog (and this entry) are my own and do not necessarily reflect the views of MySQL AB

Ever since I wrote my blog entry about Google Gears and the query tool for the browser embedded offline Google Gears database service, I have been wondering how MySQL might fit in here.

I have heard an idea to write a MySQL storage engine for SQLite and although I do not think this is necessarily a bad idea, I don’t think it will be immediately useful for typical applications powered by Google Gears. Personally, I think the following things might be of more use:

A modification of the Google Gears browser extension that allows a local MySQL database to be used instead of the embedded SQLite database

This would be interesting in case you would need a particular MySQL feature that is not available in SQLite. I’m thinking mainly of stored procedures but more so about replication.

The local MySQL server could be setup as a master that replicates to a remote slave. The remote slave would be hosted by your company and that backend would somehow merge all the private slaves from its employees into the corporate database.

Of course, the idea for the SQLite storage engine could fit here too - a local MySQL Server with the SQLite storage engine could be set up as master to replicate to the corporate slave.

A Google Gears Worker Pool application that synchronizes the embedded SQLite database with the remote, corporate MySQL database

This idea would of course require some server component that may be accessed by the Worker application, and it would presumably take the form of a web-service. This could be implemented either as a piece of middleware that sits in a HTTP server or as a component that is part of the MySQL server itself. This product would achieve in part the same functionality as replication from the client’s master to the remote slave but I think there are a number of advantages here.

First of all, the implementation would not be intrusive to Google Gears - users can still use the ordinary Google Gears extension, and MySQL AB does not need to ensure that their modifications to the browser extension are compatible with future Google Gears developments.

Second, this application could in principle allow a true synchronization rather than just replication. In other words, it could pull data from the corporate database as needed, and push local modifications to be merged with the remote database. Obviously the possibilities here would depend on the flexibility of the server-side component accessed by the worker pool application.

Thirdly, users would not need to install an extra MySQL server on their webclient host. Arguably this could be seen as a disadvantage for MySQL AB as it would result in fewer installations of MySQL Server, but personally I don’t think this is the right angle. I think that for most people, an extra MySQL Server that sits on their machine just for the purpose of replication will not be very attractive.

To me, using the Google Gears Worker Pool to drive synchronization seems like the most sensible choice that fits good with the whole offline-web idea. But what do you think? Can MySQL play a role in the offline web like SQLite can now?