I am running c-lightning with a pruned bitcoind backend. Every day at around the same time, c-lightning asks for a specific block which is already pruned, which looks like this in the logfile (block 540574 in this case):
2021-07-25T10:06:49.026Z UNUSUAL plugin-bcli: bitcoin-cli -rpcuser=... -rpcpassword=... getblock 00000000000000000010b0d763e1835bdb9921ae4b8adbb6d88d8cfcfbc392aa 0 exited with status 1
According to this comment from Christian, it is safe to ignore this warning. But because it appears every second in the logs and it feels spammy, I restart c-lighting and the error is gone until the other block (block 564180) is missing. Then I get the same message in the logs but for block 564180, also at around the same time every day.
I am pretty sure the two blocks have nothing to do with each other and also the blocks are probably specific to a channel (or two) I've opened with my node. So my question in the title is maybe a little bit misleading. That it happens with two blocks is probably also just a coincidence. But what my "real" questions are:
- Why is the error gone after a restart? Does c-lightning "forget" it wanted to know about that specific block?
- Why does the error appear at around the same time every day?
If this isn't the place to ask this, please tell me! I thought about opening an issue on github. Wasn't sure about this.