search

mit-dci / utreexo

accumulator for bitcoin utxo set
MIT License
323 stars 60 forks source link

csn/ibd: Don't set UTXOs to be remembered #309

Closed kcalvinalvin closed 3 years ago

kcalvinalvin commented 3 years ago

UTXOs are currently marked with ttl value of 0. Since 0 < 1000 is true, the pollard was remembering all the UTXOs ever, leading to a ton of memory usage. With this change, CSNs see a lot less memory usage.

This PR still sees the remembered leaves growing over time so there might still be a problem yet to be fixed.

dergoegge commented 3 years ago

Does the size of the pollard grow even if ttls are not used at all?

kcalvinalvin commented 3 years ago

Does the size of the pollard grow even if ttls are not used at all?

We still remember them so it does take up space. You can test it out on the master branch by commenting out this code https://github.com/mit-dci/utreexo/blob/0c940de7b6d9ff864e8a1d1282298e7cbc8f7202/accumulator/pollard.go#L151-L154

With it commented out, the CSN barely uses any memory. With it, CSNs go up to 7GB around block 1,300,000 on testnet3