Modules breaking or incompatible with external and aggressive caching
This is a question that had been asked before and discussed elsewhere. For instance, https://wiki.fourkitchens.com/display/PF/Modules+that+break+caching%2C+a... provides a list of modules that break the external and aggressive caching - some of them does not play well with normal cache either.
I need Drupal for Facebook and Organic Groups, both of which are listed as incompatible when external cache setting in the performance page is enabled.
Read moreProblem with Drupal cache functions (D5.16)
Reviewing codes for cache functions in Drupal 5 core, I believe I have found some flaws in them.
Following is the section of cache_clear_all() in includes/cache.inc,
<?php
121: function cache_clear_all($cid = NULL, $table = NULL, $wildcard = FALSE) {
// ... ... ...
129: if (empty($cid)) {
130: if (variable_get('cache_lifetime', 0)) {
131: // We store the time in the current user's $user->cache variable which
132: // will be saved into the sessions table by sess_write(). We then
