Memory leak related to "triggered priming query"
Periodically (once a day maybe) I see in the logs a big burst of messages "kresd[27686]: [primin] triggered priming query, next in 0 seconds" (about a thousand of them). In a monitoring graphs I see RAM usage jumps about this time nearly in each case and doesn't come back. Currently kresd's RSS has grown to 1.4Gib.
Messages between these bursts look like this:
Oct 01 22:45:38 kresd[27686]: [primin] triggered priming query, next in 0 seconds
Oct 01 22:45:39 kresd[27686]: [primin] triggered priming query, next in 0 seconds
Oct 01 22:45:39 kresd[27686]: [primin] triggered priming query, next in 86400 seconds
Oct 02 16:53:42 kresd[27686]: [taupd ] refreshing TA for .
Oct 02 16:53:42 kresd[27686]: [tasign] signalling query triggered: _ta-123-abc.
Oct 02 16:53:42 kresd[27686]: [taupd ] you need to update package with trust anchors in "/usr/share/dns/root.key" before it breaks
Oct 02 16:53:42 kresd[27686]: [taupd ] next refresh for . in 24 hours
Oct 02 22:45:39 kresd[27686]: [primin] triggered priming query, next in 21753 seconds
Oct 03 04:48:12 kresd[27686]: [primin] triggered priming query, next in 0 seconds
Oct 03 04:48:12 kresd[27686]: [primin] triggered priming query, next in 0 seconds
Versions:
ii knot-dnsutils 3.1.1-cznic.1 amd64 DNS clients provided with Knot DNS (kdig, knsupdate)
ii knot-resolver 5.6.0-cznic.1 amd64 caching, DNSSEC-validating DNS resolver
ii knot-resolver-module-http 5.6.0-cznic.1 all HTTP module for Knot Resolver
ii knot-resolver-release 1.10-1 all Knot Resolver official upstream repositories
ii libknot12:amd64 3.1.1-cznic.1 amd64 DNS shared library from Knot DNS
Ubuntu 18.04
Config:
log_level('info')
net.listen('127.0.0.53', 53, { kind = 'dns' })
modules = {
'hints > iterate',
'stats',
'predict',
}
cache.size = 100 * MB