No. Any data which is not needed anymore due to update/delete of table rows will be immediately released. This is why ETS can in some cases work better than regular data structures, because it doesn’t put any pressure on the garbage collector, and can therefore give you a more consistent latency (i.e. less variations due to unexpected GCs). I blogged about that technique here.

In general I’d recommend carefully choosing keys, and not storing needless data there, precisely because of the reason you mention. More generally, ETS or not, I wouldn’t expect a lookup by a 10MB key to perform well As usual, measuring is the best way to verify if performance is satisfactory

Thanks for the great explanation!!!

I was considering using ETS tables to implement something like in-memory indexes to other data – and wanted to make sure I wasn’t going to get into too much trouble