pruneblockchain should be able to increase the size of pruned blockchain #24286

Is it possible to update pruneblockchain command so it can also increase the size of pruned blockchain?

It seems to me that now it is only able to decrease it:

bitcoin@server:~$ bitcoin-cli pruneblockchain 650000
error code: -8
error message:
Blockchain is shorter than the attempted prune height.

One can set higher -prune=### parameter and wait until the extra blocks get mined/downloaded. It is quite hard to un-prune without doing IBD (from the genesis block).

It is quite hard to un-prune without doing IBD (from the genesis block).

Should be much easier now that #20295 rpc: getblockfrompeer has been merged

I think both this issue and #19807 can be closed simply because after we erase undo data, there is no way to recover it without re-syncing from genesis.

If a user wants to keep more data on disk like @carnhofdaki said, you can increase the -prune value and wait for it to fill up with new blocks.

If a user just wants pre-prune block data for wallet rescans, I think using neutrino filters and getblockfrompeer would be a cool feature, see https://github.com/bitcoin/bitcoin/issues/21267

If a user just wants pre-prune block data for wallet rescans, I think using neutrino filters and getblockfrompeer would be a cool feature, see #21267

yeah @pinheadmz, I would say to unify all this issues into a single one. So can send progress updates and we can make reviewers calls if the sub-projects require review.

Ok, closing this for now as duplicate of #19807 which has a bit more active discussion. Will try to close that one as well in favor of #21267 if OP agrees. @prusnak please feel free to comment if you think we need to keep this one open as well.

Ack