We know full-node will remove all pending transactions but keeps value address after global snapshot. In the local snapshot, after reading the article: Coming Up: Local Snapshots, we know full-node maintainer need choose a confirmed transaction that is sufficiently old and use this transaction as an “anchor” for the local snapshot and clean the old transactions before the "anchor", my question is: The pending transactions should be removed after local snapshot?

  • No: It pending transactions have not removed after local snapshot, the size of IRI database will still very big after local snapshot, especially after a SPAM attack (SPAMer will issue large numbers of tips and they all, not solid, e.g: invalid or no Parent transactions, like this transaction that was pending 2 months).

  • Yes: The pending transactions will be removed. But how to do the local snapshot announcement? in the Global snapshot ... it will be announced on IOTA discord. But how about local snapshot? If I issue a transaction by random choice a public full-node, and the node makes a local snapshot immediately and my transaction still pending. My transaction will be removed and I have no idea the reason is the local snapshot.

1 Answer 1


In one of the recent updates, due to performance issues caused by spamming ("side tangle") there was introduced a requirement, that transactions to be selected as a tip need to be confirming a sufficiently recent milestone N (i. e. there may not be any path to an older milestone that does not go through milestone N.

I am not involved in the implementation of local snapshots, but for me that change looked like the ideal situation for local snapshots. When pruning at some anchor, the node should™ make sure that this anchor itself is no longer eligible for tip selection based on the rule above. In that case, all unconfirmed transactions that are also no longer eligible for tip selection can be pruned. More recent unconfirmed transactions which are still eligible for tip selection have to stay.

It may still happen that you may come back after a day, find your transaction unconfirmed (or missing) and try to reattach it. The light wallet cannot reattach a transaction that "is not there any more", but I think the Trinity wallet can do it (when doing it on the same machine that initially published the transaction).


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