Querying DNS seeds too frequently #15434
Description
Despite being running most of the time, and having a database of tens of thousands of peers, my node seems to query the DNS seeds each time I restart it, which doesn't seem ideal from a privacy perspective?
eg from my debug.log:
2018-10-25T18:03:51Z Loaded 70360 addresses from peers.dat 172ms
2018-10-25T18:04:02Z Loading addresses from DNS seeds (could take a while)
2018-10-28T23:00:06Z Loaded 70368 addresses from peers.dat 153ms
2018-10-28T23:00:17Z Loading addresses from DNS seeds (could take a while)
2018-11-18T21:06:11Z Loaded 70033 addresses from peers.dat 1105ms
2018-11-18T21:06:22Z Loading addresses from DNS seeds (could take a while)
2018-12-19T06:37:23Z Loaded 71275 addresses from peers.dat 1953ms
2018-12-19T06:37:34Z Loading addresses from DNS seeds (could take a while)
2018-12-27T08:03:36Z Loaded 71670 addresses from peers.dat 1259ms
2018-12-27T08:03:47Z Loading addresses from DNS seeds (could take a while)
2019-02-18T08:46:48Z Loaded 70040 addresses from peers.dat 165ms
2019-02-18T08:46:59Z Loading addresses from DNS seeds (could take a while)
I think this is due to (1) many of the peers in my peers.dat not being alive, which means that (2) most outgoing connection attempts fail and stall for 5 seconds (nConnectTimeout), so (3) since the DNS seed thread waits for 11 seconds, only 3 or 4 attempts are generally made, with only 0 or 1 peers successfully connecting, so the threshold of 2 or more relevant peers isn't reached.
It might make sense to increase the DNS threads sleep time correspondingly? Something like:
- if (!interruptNet.sleep_for(std::chrono::seconds(11)))
+ if (!interruptNet.sleep_for(std::chrono::milliseconds(nConnectTimeout * 7)))
perhaps?