On Feb 22, 2013, at 6:33 PM, Greg Grossmeier greg@wikimedia.org wrote:

Hello all,

Background and longer/more detailed discussion on this issue is in bug 44570: https://bugzilla.wikimedia.org/show_bug.cgi?id=44570

Summary: As w

e delete old -wmfX branches there appears to be cached pages that reference old branch URLs, eg: https://bits.wikimedia.org/static-1.21wmf1/skins/common/images/poweredby_med...

(that 404s because 1.21wmf1 is long gone)

If you want to see my bad ASCII art representation of our current caching layers, see this page: http://wikitech.wikimedia.org/view/Caching_overview

So possible ways forward

option 1:

• reduce parsercache timeout to size of deployment window (~28 days) [0]
• Tim may have knowledge why that shouldn't happen [1]

Well, the obvious thing to do and imho what we should do, like, *right now* is extend the lifetime of the old branch to the timeout of the cache.

Simply not deleting a directory is very, very easy.

As far as I'm concerned we can agree right now not to delete any old branch from the servers until further notice (until we've figured out the max time age, and then implement the guard in multiversion/deleteMediawiki and then remove then when possible).

option 2:

• change away from version numbers in URLs [2]

** maybe use slots or something else ** skins?

My bugzilla comment doesn't' suggest to change away from using these version numbers. It suggest to not use these urls directly in any code that makes it to the main html output.

[0] https://bugzilla.wikimedia.org/show_bug.cgi?id=44570#c14 [1] https://bugzilla.wikimedia.org/show_bug.cgi?id=44570#c12 [2] https://bugzilla.wikimedia.org/show_bug.cgi?id=44570#c15