Launchpad itself

Possible race condition in branch puller causing OOPS

Bug #210031 reported by Jonathan Lange
2
Affects Status Importance Assigned to Milestone
Launchpad itself
Fix Released
High
Jonathan Lange

Bug Description

See OOPS-821SMPU28.

The puller is saying that the branches that it tries to mirror are "Not a branch". And yet, by the time the OOPS report comes around, there is no problem with the branch.

My initial suspicion is that it's some sort of race condition, perhaps due to some failure / misunderstanding of branch locking.

Exception type: NotBranchError
Exception value: Not a branch: "/srv/bazaar.launchpad.net/push-branches/00/00/2b/f9/.bzr/branch/".

See original description
Tags: lp-code oops
Diogo Matsubara (matsubara)
description: updated
Revision history for this message
Jonathan Lange (jml) wrote :

This may also be the cause of InstallFailed errors, as mentioned in OOPS-906SMPU119

<mwhudson> jml: every time i've look at an installfailed oops, the branch has been fine the next time
<jml> mwhudson: as in, the db records a successful mirror?
<mwhudson> yes
<mwhudson> by the time the oops report comes around even
<mwhudson> i've not been systematic about it though
<jml> in that case, I reckon that it's tied to the request_mirror race bug.

Revision history for this message
Tim Penhey (thumper) wrote :

Is this covered by work you are doing?

Changed in launchpad-bazaar:
assignee: nobody → jml
Revision history for this message
Jonathan Lange (jml) wrote :

I hope so. The "only branch unlock" thing I landed should go some way to reducing the instances of this bug, but I'm not sure whether it will fully fix it.

Essentially, we made the code only request a mirror on branch unlock. If the client unlocks the branch twice during creation, say, then the bug will still continue.

When I get back on Monday I'll gather all the bugs related to this issue. Not sure how to QA without real-time access to staging OOPS logs.

Revision history for this message
Jonathan Lange (jml) wrote :

The OOPS reports we were getting from this have disappeared. Will keep an eye open for InstallFailed errors.

Changed in launchpad-bazaar:
importance: Undecided → High
status: New → Fix Released
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