systemd-resolved very slow 5s+ under load
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resolve
- Dominant language
- C
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Description
systemd 244
Ubuntu Server 20.04
I noticed that under production load, maybe a couple hundred DNS queries per second, the resolver takes 10+ seconds to resolve a domain.
UNDER LOAD
resolvectl query archlinux.org
archlinux.org: 138.201.81.199 -- link: enp5s0f0
2a01:4f8:172:1d86::1 -- link: enp5s0f0
-- Information acquired via protocol DNS in 10.5834s.
-- Data is authenticated: no
NO LOAD
resolvectl query archlinux.org
archlinux.org: 138.201.81.199 -- link: enp5s0f0
2a01:4f8:172:1d86::1 -- link: enp5s0f0
-- Information acquired via protocol DNS in 20.8ms.
-- Data is authenticated: no
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reproducing the reported contrast with resolvectl query archlinux.org on systemd 244 and Ubuntu Server 20.04, both without load and at the reported query rate. Investigate the resolver's behavior under load and document the cause and a verified resolution for the 10+ second latency.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- c, linux
- Domain
- networking, operating-systems
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 35/100