696179 - search engine "alias" getter caching is broken, results in many unnecessary synchronous SQLite reads when entering text in the location bar

Status: RESOLVED FIXED

(Firefox :: Search, defect)

Description

[:Gavin Sharp [email: [e-mail]]]

We iterate over all engines and retrieve their "alias" to compare to the entered text (for triggering search engines using a keyword). Unfortunately the getter for the alias doesn't cache a null result, which means that we end up hitting SQLite for the value multiple times in the common case (engines not having an alias).

(Jeff was seeing this hit the disk every time, which seems like a failure of caching for SQLite, since this DB is very small and should fit in memory. That's a separate issue that needs investigation though.)

Comment 1

[:Gavin Sharp [email: [e-mail]]]

Attachment: patch

Comment 2

[Jeff Muizelaar [:jrmuizel]]

(In reply to Gavin Sharp (use [e-mail] for email) from comment #0)
> (Jeff was seeing this hit the disk every time, which seems like a failure of
> caching for SQLite, since this DB is very small and should fit in memory.
> That's a separate issue that needs investigation though.)

It appears as though this was just rereading of the lock page, which is expected. I have however filed a bug on getting rid of that read too: bug 696364.

Comment 3

[:Gavin Sharp [email: [e-mail]]]

Attachment: patch

I changed my mind about this after thinking about the "alias" getter - I think it's best to have aliases continue to be |null| if they're not set, rather than |""|. So to preserve that behavior I'm just switching to use "undefined" as the uninitialized value.

Comment 4

[:Gavin Sharp [email: [e-mail]]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/3cf9011b5494

Comment 5

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/3cf9011b5494