Bug ID 476476: Occasional inability to cache optimized PDFs and images

Last Modified: Apr 10, 2019

Bug Tracker

Affected Product:  See more info
BIG-IP AAM(all modules)

Known Affected Versions:
11.3.0, 11.4.0, 11.4.1, 11.5.0, 11.5.1, 11.5.1 HF1, 11.5.1 HF10, 11.5.1 HF11, 11.5.1 HF2, 11.5.1 HF3, 11.5.1 HF4, 11.5.1 HF5, 11.5.1 HF6, 11.5.1 HF7, 11.5.1 HF8, 11.5.1 HF9, 11.5.2, 11.5.2 HF1, 11.5.3, 11.5.3 HF1, 11.5.3 HF2, 11.6.0, 11.6.0 HF1, 11.6.0 HF2, 11.6.0 HF3, 11.6.0 HF4, 11.6.0 HF5, 11.6.0 HF6, 11.6.0 HF7, 11.6.0 HF8, 11.6.1

Fixed In:
12.0.0, 11.6.1 HF1, 11.5.4, 11.4.1 HF9

Opened: Aug 22, 2014
Severity: 3-Major
Related AskF5 Article:
K16113

Symptoms

Restarting the datastor service can result in some optimized PDFs or optimized images becoming un-cacheable

Impact

Certain URLs become uncacheable, thus reducing effectiveness of WAM.

Conditions

If WAM has a handle to cached content in datastor which no longer exists because datastor restarted or evicted it, and if this content is an image or PDF which WAM optimized, and if two requests for such content arrive on the same TCP connection, the second can get incorrectly cached such that it can not be served or replaced until tmm is restarted.

Workaround

Disable client keep-alive in the HTTP profile (change Maximum Requests in the HTTP profile from 0 to 1) or disable PDF linearization and image optimization. A partial workaround is to use wa_clear_cache instead of restarting datastor to clear the cache. Content which datastor evicts might still suffer (but this is unlikely).

Fix Information

Restarting datastor no longer results in the possibility of some optimized PDFs or optimized images becoming uncacheable.

Behavior Change