If the peer (whether pruned or not itself) supports sending pruned blocks
to syncing nodes, the pruned version will be sent along with the hash
of the pruned data and the block weight. The original tx hashes can be
reconstructed from the pruned txes and theur prunable data hash. Those
hashes and the block weights are hashes and checked against the set of
precompiled hashes, ensuring the data we received is the original data.
It is currently not possible to use this system when not using the set
of precompiled hashes, since block weights can not otherwise be checked
for validity.
This is off by default for now, and is enabled by --sync-pruned-blocks
The blockchain prunes seven eighths of prunable tx data.
This saves about two thirds of the blockchain size, while
keeping the node useful as a sync source for an eighth
of the blockchain.
No other data is currently pruned.
There are three ways to prune a blockchain:
- run monerod with --prune-blockchain
- run "prune_blockchain" in the monerod console
- run the monero-blockchain-prune utility
The first two will prune in place. Due to how LMDB works, this
will not reduce the blockchain size on disk. Instead, it will
mark parts of the file as free, so that future data will use
that free space, causing the file to not grow until free space
grows scarce.
The third way will create a second database, a pruned copy of
the original one. Since this is a new file, this one will be
smaller than the original one.
Once the database is pruned, it will stay pruned as it syncs.
That is, there is no need to use --prune-blockchain again, etc.
Fix sync wedge corner case:
It could happen if a connection went into standby mode, while
it was the one which had requested the next span, and that span
was still waiting for the data, and that peer is not on the
main chain. Other peers can then start asking for that data
again and again, but never get it as only that forked peer does.
And various other fixes
Connections can be dropped by the net_node layer,
unbeknownst to cryptonote_protocol, which would then
not flush any spans scheduled to that connection,
which would cause it to be only downloaded again
once it becomes the next span (possibly after a small
delay if it had been requested less than 5 seconds
ago).
A block queue is now placed between block download and
block processing. Blocks are now requested only from one
peer (unless starved).
Includes a new sync_info coommand.
