[Feature]: store/v2: support archive node migration

[kocubinski]

Summary

store/v2 migrations support migrating from a snapshot, which is ideal for a high throughput validator, but this does not account for migrating (or after migration, retrieving) historical state.

Problem Definition

Today, after migrating to store/v2, historical state present prior to the snapshot used for migration is no longer accessible to the state machine or query handlers.

Proposed Feature

1. A migration path for all store/v1 SC keys into store/v2 SS
2. In lieu of (1), store/v2 should fall back to the store/v1 SC database on version miss.

[tac0turtle]

we should be able to offer a simple command line to transfer the data for node operators that would like to

[kocubinski]

Since SS was removed from store/v2 in #22683 this is no longer relevant.

[tac0turtle]

we should still have migration for iavlv2 no?

[kocubinski]

iavl v2 could use some attention for migrations. presently the only supported migration is iavl v0 -> iavl v2, and that is latest state only. should that be a feature of iavl v2 or store/v2 though?

[tac0turtle]

i was thinking a cmd that uses that the user runs and does gets and sets, it will be slow but its the best we can do

[kocubinski]

so migrate between 2 arbitrary SC stores?

[kocubinski]

for historical state recovery, this is not trivial. I wrote a tool to recover the full state log from an iavl v0 db on TB scale and it takes on the order of 12-48 hours to run.

re opening for now, let's discuss synchronously on tomorrow's SDK call?

[tac0turtle]

closing this after the previous discussion