Based on #26626
This PR changes the legacy to descriptor wallet migration from creating a new combo() for every individual key to creating one large combo() that has a list of every key. This improves the performance of the migrated wallet as it will only have one DescriptorSPKM for all of the non-HD keys.
Note that this does not affect previously migrated wallets. Such wallets will still have a combo() for every key.
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Wouldn't #20018 address most performance concerns of having a large number of
DescriptorSPKMs? Albeit at the cost of a slightly higher memory footprint, especially in this case.
Yes, but these approaches aren't mutually exclusive, and I'd like to get feedback on both.
ListPubkeyProvider is a ranged PubkeyProvider that returns individual
public keys that it was constructed with.
A new KEY expression is introduced which takes a list of non-ranged
public keys. This expression itself is ranged and can provide the key at
a particular index. It can take any KEY as long as it is not ranged.
Instead of having several thousand individual combo descriptors, have a
single large combo descriptor with a list of keys. This will improve
performance in IsMine and other similar areas.