1702332 - 4x-10x jump in number of DNS queries starting Feb 8th

Status: RESOLVED FIXED

(Core :: Networking: DNS, task, P2)

Description

[Trevor Rowbotham [:rowbot]]

Attachment: queries chart

I am seeing a 4x-10x jump in number of DNS queries when using Nightly. This started Feb 8th as shown in the chart image. I don't believe my browsing habits have changed. I'll try to test a build from before the 8th sometime this week to confirm.

I am using NextDNS with DoH. All my other devices have remained constant, so I don't think its an issue with NextDNS. I've tried a new profile, disabling addons, and disabling http3, but nothing has changed.

Comment 1

[Trevor Rowbotham [:rowbot]]

Attachment: about.support.txt

Comment 2

[Trevor Rowbotham [:rowbot]]

Tentative regression range: https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=7c861a1895759bd3878692c4e01f17a9b1a6847b&tochange=6b0fbffe2432584fb9e2b303beafd3aecf6bce7a

I'll try to see if I can narrow it down further over the next day or so.

Comment 3

[Kershaw Chang [:kershaw]]

I think this should be caused by bug 1686421. This pref network.dns.upgrade_with_https_rr is enabled, so we do one additional DNS query for every http request. Could you try to disable this pref and see if it helps?

Comment 4

[Trevor Rowbotham [:rowbot]]

Disabling network.dns.upgrade_with_https_rr seems to have helped tremendously. Currently sitting at ~4k queries for the day, though my browsing has been on the lighter side today. Still much better than the ~20k queries per day I was seeing after the pref got enabled.

Comment 5

[Kershaw Chang [:kershaw]]

(In reply to Trevor Rowbotham [:rowbot] from comment #4)

Disabling network.dns.upgrade_with_https_rr seems to have helped tremendously. Currently sitting at ~4k queries for the day, though my browsing has been on the lighter side today. Still much better than the ~20k queries per day I was seeing after the pref got enabled.

Thanks for testing!
In theory, we should have 2 times of DNS queries when enabling this feature. I think we need to investigate the total amount of DNS queries before shipping this HTTPS RR.

Comment 6

[Kershaw Chang [:kershaw]]

Attachment: Bug 1702332 - Reduce the amount of DNS queries for unavailable type records, r=#necko

Comment 7

[Trevor Rowbotham [:rowbot]]

After having browsed for a week with network.dns.upgrade_with_https_rr disabled, I am still seeing double the number of queries that I was previously getting. So, I believe there is another change that landed the same day that also caused an increase in the number of queries being made.

Comment 8

[Kershaw Chang [:kershaw]]

(In reply to Trevor Rowbotham [:rowbot] from comment #7)

After having browsed for a week with network.dns.upgrade_with_https_rr disabled, I am still seeing double the number of queries that I was previously getting. So, I believe there is another change that landed the same day that also caused an increase in the number of queries being made.

There is another pref network.dns.use_https_rr_as_altsvc that also creates DNS queries for HTTPS RR. You can also disable it if you want.

Comment 9

[Kershaw Chang [:kershaw]]

Attachment: Bug 1702332 - Add a test for returning a negative result, r=#necko

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/7785438d5527
Reduce the amount of DNS queries for unavailable type records, r=necko-reviewers,valentin
https://hg.mozilla.org/integration/autoland/rev/1458eb0164ea
Add a test for returning a negative result, r=necko-reviewers,valentin

Comment 11

[Dorel Luca [:dluca]]

https://hg.mozilla.org/mozilla-central/rev/7785438d5527
https://hg.mozilla.org/mozilla-central/rev/1458eb0164ea