It's disabled by default because, if I remember correctly, its performance is very poor on larger update operations. However, you are correct of course that it somewhat compromises on the failsafe aspect of the store.
I'm not against making it enabled by default, especially if we can combine that with certain options to cater for bulk uploads or other things to mitigate performance loss. I would like some recent comparative benchmarks though to see what the actual performance degradation is on various kinds of update operation. I can live with some degradation, but if we're suddenly 150% slower on every write operation, that's a bit much.
As for bulk uploads, not sure what you have in mind there but one relatively simple option might be to look at the transaction isolation level. For example, we could enable force sync by default, but then turn it off if a transaction with isolation level NONE comes in (which is typically the isolation we recommend using for bulk uploads). This is an off the cuff idea and I have no idea how that would play out in the face of concurrent transactions, to be honest, but it might be worth looking at.
Cheers,
Jeen
