Greg wrote:
> What about also making input prevouts filter based on the scriptpubkey being
> _spent_? Layering wise in the processing it's a bit ugly, but if you
> validated the block you have the data needed.
AFAICT, this would mean that in order for a new node to catch up the filter
index (index all historical blocks), they'd either need to: build up a
utxo-set in memory during indexing, or would require a txindex in order to
look up the prev out's script. The first option increases the memory load
during indexing, and the second requires nodes to have a transaction index
(and would also add considerable I/O load). When proceeding from tip, this
doesn't add any additional load assuming that your synchronously index the
block as you validate it, otherwise the utxo set will already have been
updated (the spent scripts removed).