937915 - Restore DB filenames in Telemetry SlowSQL strings

Status: RESOLVED FIXED

(Toolkit :: Telemetry, defect)

Description

[Vladan Djeric (:vladan)]

Attachment: always append the DB name as a comment

bug 896737 accidentally caused us to stop reporting the DB filenames in Telemetry slowSQL strings

Comment 1

[David Teller [:Yoric] - still alive but not very active]

Comment on attachment 831166 [details] [diff] [review]
always append the DB name as a comment

Review of attachment 831166 [details] [diff] [review]:
-----------------------------------------------------------------

r=me, with the changes below

::: toolkit/components/telemetry/Telemetry.cpp
@@ +2029,2 @@
>      }
> +    sanitizedSQL.AppendPrintf(" /* %s */", dbName.BeginReading());

If I recall correctly, the chartype* returned by BeginReading() is not necessarily 0-terminated. I'd be more comfortable with a series of calls to Append().

@@ +2036,5 @@
>      StoreSlowSQL(aggregate, delay, Sanitized);
>    }
>  
>    nsAutoCString fullSQL(sql);
> +  fullSQL.AppendPrintf(" /* %s */", dbName.BeginReading());

Same here.

Comment 2

[Vladan Djeric (:vladan)]

nsString/nsCString are guaranteed to be null-terminated, and nsAutoCString is derived from nsCString

https://developer.mozilla.org/en-US/docs/Mozilla_internal_string_guide#The_Major_String_Classes

I could use get() if you prefer?

https://developer.mozilla.org/en-US/docs/nsAutoString#get

Your call.

Comment 3

[David Teller [:Yoric] - still alive but not very active]

(In reply to Vladan Djeric (:vladan) from comment #2)
> nsString/nsCString are guaranteed to be null-terminated, and nsAutoCString
> is derived from nsCString

Well, yes, but you are using a nsACString argument which has no such guarantee. I seem to remember that you should nsPromiseFlatCString()-ify it before you call get() or BeginReading(). Which should be a no-copy if your string is a nsAutoCString.

Comment 4

[Vladan Djeric (:vladan)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/6d8762404e6f

Comment 5

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/6d8762404e6f

Comment 6

[Vladan Djeric (:vladan)]

Comment on attachment 831166 [details] [diff] [review]
always append the DB name as a comment

[Approval Request Comment]
Bug caused by (feature/regressing bug #): bug 896737
User impact if declined: None, but Telemetry data collected by Firefox will be incomplete
Testing completed (on m-c, etc.): Tested locally and on Nightly for a couple of days
Risk to taking this patch (and alternatives if risky): None really
String or IDL/UUID changes made by this patch: None

Comment 7

[Vladan Djeric (:vladan)]

https://hg.mozilla.org/releases/mozilla-aurora/rev/07e7f637e2a4
https://hg.mozilla.org/releases/mozilla-beta/rev/158aeb4c6657