Possible sendtoaddress improvement? #15885

I've been going through all the code that runs to serve a "sendtoaddress" call, to find potential improvements.

One control flow path looks like: sendtoaddress -> SendMoney -> CreateTransaction -> AvailableCoins + SelectCoins

Now, AvailableCoins iterates upon all the txn entries in the wallet and stores usable ones into a list. This list is later trimmed down by SelectCoins.

So, we end up building a huge list every time sendtoaddress is called, only to trim it down later.

Wouldn't it be better if we could tell AvailableCoins to only select coins of required value?

I think the nMinimumSumAmount parameter in AvailableCoins was made for this purpose only?

How expensive of an operation is it to create the list compared to running the selection logic and signing?

Wouldn't it be better if we could tell AvailableCoins to only select coins of required value?

SelectCoins needs all of them in order to select the best set for the target value.

I think the nMinimumSumAmount parameter in AvailableCoins was made for this purpose only?

No, it was added for listunspent.

Closing for now. Though, improvements are definitely welcome as pull requests