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PLACES_EXPIRATION_STEPS_TO_CLEAN telemetry might be misleading

RESOLVED FIXED in Firefox 17

Status

()

Firefox
Bookmarks & History
RESOLVED FIXED
5 years ago
5 years ago

People

(Reporter: briansmith, Assigned: froydnj)

Tracking

Trunk
Firefox 17
Points:
---
Dependency tree / graph

Firefox Tracking Flags

(firefox13-, firefox14-, firefox15-, firefox16-)

Details

Attachments

(1 attachment)

+++ This bug was initially created as a clone of Bug #763359 +++

Please see my investigation in bug 763351 and Bug 763359.

A linear histogram with range (1, n) specified to have n buckets will actually have (n+1) buckets with a range slightly less than 1, instead of n buckets with range of 1. Consequently, sometimes two distinct values will get mapped into the same bucket. For example, in bug 763351, the values 2 and 3 both got mapped into the 2 bucket.

Since this probe seems to want to measure an integral number of steps, it seems like a good idea to change the probe to avoid this issue.
How is current code handling this issue? Just creating n+1 buckets?
Blocks: 764260
(In reply to dev from comment #1)
> How is current code handling this issue? Just creating n+1 buckets?

Yes, if you are storing counts or other integers in buckets that aren't enums.

For enums, (e.g. SSL cipher suites), you can use HISTOGRAM_ENUMERATED_VALUES.
likely we may just fix the number of buckets here, the thing we care most is that this measure stays low (under 5), so the actual value has less importance. We will just get more precice infos once the fix gets out in the wild.
tracking-firefox13: ? → -
tracking-firefox14: ? → +
tracking-firefox15: ? → +
tracking-firefox16: ? → +
Not sure I understand the tracking 14+ flags here - this isn't something that's crucial to fix ASAP, is it?
(Assignee)

Updated

5 years ago
Blocks: 763359
No longer depends on: 763359
(In reply to :Gavin Sharp (use gavin@gavinsharp.com for email) from comment #4)
> Not sure I understand the tracking 14+ flags here - this isn't something
> that's crucial to fix ASAP, is it?

nope, as I said in comment 3, we may just fix the measure and get new results, but not high priority.
OK, un-tracking for 14.
tracking-firefox14: + → -
taking off tracking for 15/16 as well since this isn't a crucial fix.
tracking-firefox15: + → -
tracking-firefox16: + → -
(Assignee)

Comment 8

5 years ago
Created attachment 649766 [details] [diff] [review]
patch

Just use HISTOGRAM_ENUMERATED_VALUES.  It doesn't sound like we're terribly attached to the exact number of buckets here.
Attachment #649766 - Flags: review?(taras.mozilla)

Comment 9

5 years ago
Comment on attachment 649766 [details] [diff] [review]
patch

looks reasonable
Attachment #649766 - Flags: review?(taras.mozilla) → review+

Comment 10

5 years ago
Comment on attachment 649766 [details] [diff] [review]
patch

however mak is the only who needs to r+ this
Attachment #649766 - Flags: review?(mak77)
Comment on attachment 649766 [details] [diff] [review]
patch

Review of attachment 649766 [details] [diff] [review]:
-----------------------------------------------------------------

thanks
Attachment #649766 - Flags: review?(mak77) → review+
(Assignee)

Comment 12

5 years ago
https://hg.mozilla.org/integration/mozilla-inbound/rev/f4e742d57ce7
Assignee: nobody → nfroyd
Status: NEW → ASSIGNED
https://hg.mozilla.org/mozilla-central/rev/f4e742d57ce7
Status: ASSIGNED → RESOLVED
Last Resolved: 5 years ago
Resolution: --- → FIXED
Target Milestone: --- → Firefox 17
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