Wallet is slow with 200k subaccounts

[SChernykh]

Reported by Antidarknet:

the official wallets are extremely unstable at 200,000 subaccounts if each has had at least one transaction in and one out. Try generating more subaccounts after 200k it takes many times longer to generate rather than when first initializing a wallet. The more accounts you add the slower it gets. Should probably fix that too. Don't take our word for it but test it yourselves.

[preland]

To be 100% clear: do we have any proof from Antidarknet that this is true?

I’m assuming that the issue is valid, but just making sure

[selsta]

200k subaccounts is likely going to require a large amount of RAM so that should be taken into account when testing.

If I remember correctly by default it creates 200 subaddresses per account, 200k accounts will lead to 40M subaddresses.

[SChernykh]

@preland It is possible, based on wallet2 code track record. We just don't know what exactly can cause it.

[plowsof]

related? #8740 , even better: #8926

[moneromooo-monero]

Also #5370, though that was more about addressing memory usage.

[Gingeropolous]

just a reminder there's a server with 256GB of memory ppl can use to test this on the monero research cluster. contact me for access if you don't have it already