> That's much more likely flash degradation than actual fragmentation. Did you use cheap tablets with eMMC storage?

My understanding of the parent reply's situation is that this was happening on the tablets of their users, so it kinda doesn't matter that it can be avoided by not using cheap tablets.

Most apps aren't in a position to tell their users that they are on their own when they run into what feels like an unreasonable app slowdown because they didn't buy a good enough device to run it on, especially when they've previously experienced it running just fine.

If all their apps feel like crap on that tablet, sure, that might fly... but if its only your app (or only a small set of apps that use SQLite in the same way the OP's company did) that feels like crap after a while, that's effectively a you problem (to solve) even if its not really a you problem.

In any case, its an interesting data point and could be very useful information to others who run into similar issues.

I don't quite understand what you're arguing here.

I'm merely saying that the root cause was misidentified - the performance degradation didn't happen due to fragmentation, but because the flash storage was degraded to the point where the write performance dropped significantly. This happens faster for eMMC vs. SSD-style storage.

Copying the DB file moved the data to different storage blocks which is why it (temporarily again) improved performance.