We are using Authcache Builtin (with memcache), Authcache Block, and Authcache Ajax. The only personalized component on the page is a block at the top being loaded in with Authcache Ajax and it displays the username of the logged-in use. I am unable to reproduce this issue but I received reports that some users were seeing the username of a different user when they logged in. The settings for the block are:

  • Cache lifetime: 6 days
  • Cache per: user
  • Enabled clients: Ajax
  • Fallback: Cancel caching

I assumed if the load failed that caching would be cancelled and the correct username would load in the block. Is this a known issue or is there any fix for this in the latest 7.x-2.x-dev release? Thanks in advance!

Comments

vinmassaro created an issue. See original summary.

vinmassaro’s picture

vinmassaro CreditAttribution: vinmassaro commented
Issue summary: View changes
znerol’s picture

znerol CreditAttribution: znerol commented

The configuration looks correct. Authcache does not support server-side caching of fragments. Therefore I cannot think of a way how fragments rendered for different users could be mixed up on the server.

I can think of a failure mode where Authcache fails to realize that the username-block should be personalized (loaded via ajax). If that applies, then every user should see the same username at a given time. If this problem occurs intermittently, then maybe there is a problem with the variable-cache. Inconsistent configuration likely would affect other parts of the site as well (throughout core/contrib). If you use features make sure that there are no conflicts. If you have some other configuration management in place, then examine that whether it has the potential to flip-flop config.

The variables are cached in the cache_bootstrap bin. Do you store that bin in memcache too? Maybe revert to the database cache backend for this bin and check whether the problem persists.

Also is there anything special about the affected users or their working environment? E.g.:

  • Do they share the very same workstation/browser?
  • Do you see a pattern in the affected browsers? E.g., are the affected users all using the same browser software/version?
  • Are there any reverse proxies (e.g. Varnish) in front of the server?
  • Are there any caching proxies (e.g. Squid at a branch-office) involved?
  • Some mobile operators employ transparent caching proxies. Is there a chance that the affected users use the same provider?
vinmassaro’s picture

vinmassaro CreditAttribution: vinmassaro commented

This is on a university network with many staff logging in, and isn't impacting everyone. I actually can't reproduce the issue, but our help desk has reported certain users seeing a username for a different user. It appears that that case is consistent, where a single user continues to see the name of a different user every time. All cache bins are stored in memcache except cache_form.

vinmassaro’s picture

vinmassaro CreditAttribution: vinmassaro commented

Ok, what's strange is that I noticed now that the name coming back is not even a username of another user in the site. The logic to do this uses global $user for the authenticated user logging in. I saw another case where the text displayed wasn't even a username.

vinmassaro’s picture

vinmassaro CreditAttribution: vinmassaro commented
Status: Active » Closed (works as designed)

This issue turned out to be an issue with the code getting the user info so I'm closing this. znerol, thanks for your quick response!