[MGNLCACHE-36] Failure to generate response first time might lead to page not being accessible w/o restart Created: 07/May/10  Updated: 04/Nov/15  Resolved: 04/Nov/15

Status: Closed
Project: Cache Modules
Component/s: None
Affects Version/s: 5.0
Fix Version/s: None

Type: Bug Priority: Major
Reporter: Jan Haderka Assignee: Unassigned
Resolution: Won't Do Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
relation
is related to MAGNOLIA-3167 cache: single blocking request can bl... Closed
Template:
Acceptance criteria:
Empty
Task DoD:
[ ]* Doc/release notes changes? Comment present?
[ ]* Downstream builds green?
[ ]* Solution information and context easily available?
[ ]* Tests
[ ]* FixVersion filled and not yet released
[ ]  Architecture Decision Record (ADR)
Bug DoR:
[ ]* Steps to reproduce, expected, and actual results filled
[ ]* Affected version filled
Date of First Response:

 Description   

If thread gets stuck forever in generating the response and creating the cache entry, the mutex from cache entry is never removed and such entry can't be served without restart of the server. The same result occurs for infinite loop, waiting for external resources w/o timeout or when thread crashes or is stopped from server maintenance tool (thread.stop() means finally blocks are not executed, thus the mutex is not removed)
Prior to fixing MAGNOLIA-3167 this would lead eventually into whole server to be blocked from serving the cached content. Since the fix issue is relevant only to the single resource.
There might be various reasons for such situation to occur such as programmer error, lack of resources on the server, waiting for external resources, etc. The variety of possible causes makes it more difficult to decide what to do in such situation. Possibilities are:

  • keep the current behavior - if the resource could not be served once, chances are it can't be served ever without fixing the code. Not working URL makes it easier to spot and fix the problem
  • remove mutex after certain time or number re-tries. This solution would make it harder to spot the pages/URLs for which problem occurs intermittently, however would allow Magnolia to recover. Another side effect is that if thread gets stuck in infinite loop due to programming error, server would be leaking threads this way eventually exhausting all the resources.


 Comments   
Comment by Michael Mühlebach [ 04/Nov/15 ]

Given the thousands of other issues we have open that are more highly requested, we won't be able to address this issue in the foreseeable future. Instead we will focus on issues with a higher impact, and more votes.
Thanks for taking the time to raise this issue. As you are no doubt aware this issue has been on our backlog for some time now with very little movement.
I'm going to close this to set expectations so the issue doesn't stay open for years with few updates. If the issue is still relevant please feel free to reopen it or create a new issue.

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