1145914 - Multiple attribute changes are queued up on server and sent over with the same values

Status: RESOLVED FIXED

(DevTools :: Inspector, defect)

Description

[Brian Grinstead [:bgrins]]

Open the inspector on https://bgrins.github.io/devtools-demos/inspector/mutations.html.

There is an attribute changing in a loop:

    for (var i = 0; i < 1000; i++) {
      document.querySelector("#toofast").setAttribute("data-toofast", toofast++);
    }

If you open the inspector on that tab and watch the protocol traffic, you'll see 1000 duplicate packets per batch like this:

    {
      "type": "attributes",
      "target": "server1.conn1.domnode107",
      "numChildren": 3,
      "attributeName": "data-toofast",
      "newValue": "5999"
    },
    {
      "type": "attributes",
      "target": "server1.conn1.domnode107",
      "numChildren": 3,
      "attributeName": "data-toofast",
      "newValue": "5999"
    },
    {
      "type": "attributes",
      "target": "server1.conn1.domnode107",
      "numChildren": 3,
      "attributeName": "data-toofast",
      "newValue": "5999"
    }

Comment 1

[Brian Grinstead [:bgrins]]

Interestingly, after the fix in Bug 1139569, the frontend doesn't care much about these duplicate packets since the attribute value hasn't changed, but we still shouldn't send them to prevent unnecessary noise

Comment 2

[Brian Grinstead [:bgrins]]

Attachment: inspector-duplicate-attribute-changes.patch

Something like this, probably

Comment 3

[Patrick Brosset <:pbro>]

(In reply to Brian Grinstead [:bgrins] from comment #2)
> https://bgrins.github.io/devtools-demos/inspector/mutations.html
You just killed my browser with this page :)

Comment 4

[Brian Grinstead [:bgrins]]

Attachment: inspector-duplicate-attribute-changes.patch

Dave, we've discussed the issue in which multiple attribute modifications get queued up and sent across in a single call to getMutations.  This patch prunes out any duplicate attribute modifications that happen within a single call to getMutations.  What do you think?  If you're too busy, please redirect the review to Patrick.

Comment 5

[Brian Grinstead [:bgrins]]

Try push: https://treeherder.mozilla.org/#/jobs?repo=try&revision=b1524b9d1d3a

Comment 6

[Brian Grinstead [:bgrins]]

https://hg.mozilla.org/integration/fx-team/rev/fde5601c5dd4

Comment 7

[Ekanan Ketunuti]

https://hg.mozilla.org/mozilla-central/rev/fde5601c5dd4