974995 - Research browser.db maintenance

Status: RESOLVED INCOMPLETE

(Firefox for Android Graveyard :: Data Providers, defect)

Description

[Michael Comella (:mcomella) [NI reported issues only: ex-Mozilla]]

e.g. vacuuming! According to mfinkle, we don't do that! :o

While we're at it, we should probably check that any other DBs we use are propery maintained.

Comment 1

[Richard Newman [:rnewman]]

Vacuuming isn't always worthwhile, as you know from FHR!

It's expensive, and it can make subsequent writes more costly.

But yes, research! Perhaps a free page percentage in FHR or telemetry would be interesting…

Comment 2

[Richard Newman [:rnewman]]

Attachment: sqlite3_analyzer output for my own browser.db

Comparing this with another DB I had, my DB contains very few thumbnails, and lots of Sync-sourced data.

You'll see that vacuuming this DB would be pointless from a free page perspective, but we're not utilizing the space well:

Size of the file in bytes......................... 4169728
Bytes of user payload stored...................... 2324873     55.8%

Unused bytes on index pages....................... 12552       76.6%
Unused bytes on primary pages..................... 698671      21.4%
Unused bytes on overflow pages.................... 15355        1.7%
Unused bytes on all pages......................... 726578      17.5%

Favicons consumes most of the space in this DB:

FAVICONS.......................................... 286         28.1%

and are very index-inefficient:

Unused bytes on index pages....................... 3420        83.5%


Probably the best thing to do from a browser.db maintenance standpoint is to not store thumbnails, and perhaps not store favicons, in the DB at all.

Comment 3

[BMO Automation]

We have completed our launch of our new Firefox on Android. The development of the new versions use GitHub for issue tracking. If the bug report still reproduces in a current version of [Firefox on Android nightly](https://play.google.com/store/apps/details?id=org.mozilla.fenix) an issue can be reported at the [Fenix GitHub project](https://github.com/mozilla-mobile/fenix/). If you want to discuss your report please use [Mozilla's chat](https://wiki.mozilla.org/Matrix#Connect_to_Matrix) server https://chat.mozilla.org and join the [#fenix](https://chat.mozilla.org/#/room/#fenix:mozilla.org) channel.