522154 - Updater should be more frugal with disk usage.

Status: RESOLVED DUPLICATE of bug 520491

(Toolkit :: Application Update, defect)

Description

[Justin Dolske [:Dolske]]

For partial updates, the updater is a bit inefficient with disk usage.

All of the patches are extracted in the Prepare phase, and the patches are not deleted until the Finish phase. This results in update data consuming 2x the MAR size throughout the entire update process, which could be a problem in low-diskspace situations.

It would be better to do one of two ways:

1) Extract everything in the Prepare phase. Then delete the MAR file. Then execute (apply) the patches, deleting them along the way.

2) Don't extract anything in the Prepare phase. For each execute step, extract the patch, apply it, then delete it.

#1 briefly has the same disk usage (until it deletes the MAR). The amount of update data drops towards 0, as it deletes patches during the update process.

#2 has a disk usage equal the MAR size plus the largest patch, and has the nice side effect of leaving the original MAR around for troubleshooting.

#2 seems slightly preferable, but I didn't think too hard about the impact of the updater making backup files as it goes, so that might have some impact.

The process for full updates is a bit different; it doesn't do anything during the Prepare phase, and just extracts the added file to it's destination during the Execute phase (making backups along the way). So, I don't see any disk space savings from changing that.

Comment 1

[Robert Strong (they/them - no direct email)]

Bug 520491 makes the updater somewhat more frugal with disk usage so adding dependency.

Comment 2

[Justin Dolske [:Dolske]]

Actually, 520491 fixes this problem (#2 from comment 0), so I'm just duping this.