> My point is instead of doing 100k transactions in your web app, you should look at how to gather them into batches.

This sounds odd to me. Assuming 100k independent web requests, a reasonable web app ought to be 100k transactions, and the database is the bottleneck. Suggesting that the web app should rework all this into one bulk transaction is ignoring the supposed value-add of the database abstraction and re-implementing it in the web app layer.

And most attempts are probably going to do it poorly. They're going to fail at maintaining the coherence and reliability of the naive solution that leaves this work to the database.

Of course, one ought to design appropriate bulk operations in a web app where there is really one client trying to accomplish batches of things. Then, you can also push the batch semantics up the stack, potentially all the way to the UX. But that's a lot different than going through heroics to merge independent client request streams into batches while telling yourself the database is not actually the bottleneck...