Caching and drupal stability problems
[I'm posting this message here, as not clear where else to turn.]
We have a Drupal-6.10 site installation, running a number of contributed modules (domain access, mailhandler, gallery, etc). The site has been having ongoing stability problems that have proven impossible to debug or diagnose. I have tried disabling various contributed modules, without success. I am starting to suspect the bug is in the core itself.
The symptom is that we get (basically) a WSOD. The only relevant logfile message is "premature end of script headers". This occurs even when there is minimal server load. I've verified that it is not a memory limitation, and I do not believe there is a php syntax error.
If I clear all caches (either using drush, update.php, or manually with mysql), the WSOD instantly goes away. I have turned off caching (in the admin/performance area), but still I see this problem.
Any suggestions how to diagnose the problem, or what may be going on?
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6.10 is 4 security and bug fix releases behind. Ensure all contrib module are also up to date.
similar threads = http://www.google.com/search?hl=en&source=hp&q=drupal+premature+end+of+s...
Will try upgrade, but...
I spent quite a bit of time searching bug reports to see if others were running into this problem. I found a couple postings, some of which indicate they are using latest 6.14 release.
For example, this post describes situation similar to what I've been seeing. (I also have to temporarily rename the modules directory just to get control of the system again.)
We will be upgrading anyway, but unless someone can point to specific bug report, I am doubtful that minor upgrade will fix this issue.
Here is the solution
In case anyone else is running into this problem, I have identified the cause.