CCK fields disappear from Content type

Question

Sometimes, during period of high traffic on sites, CCK input fields disappear while adding a content from the backend. I haven't enabled the throttle module. The fields are restored automatically at other times.

For example - field for image upload, checkbox for featured for a content type News disappear during heavy traffic but get automatically restored during other times.

What could be a cause?

Does Drupal have an internal throttling mechanism during times of heavy traffic?

Answer 1

Does Drupal have an internal throttling mechanism during times of heavy traffic?

No. Throttle was an attempt to do this, but it is genrally not used. As you have this off it is not going to be the cause.

I would suggest tweeking your performance settings to see if you can get peak load to not affect your systems so much.

Answer 2

To me this indicates problems with your database. Try optimizing your database in the following ways

1. Increase the caching RAM available
2. Change your tables from MyISAM to InnoDB. InnoDB is more reliable in periods of high traffic.
3. Try moving the session handling to memcache ( search for "drupal session handling memcache" or some similar string on google to find out how to do this). This decreases server load significantly.
4. Do some debugging and see what are the slow queries, I'm sure CCK is a culprit. You can use the devel module to see slow queries or go into the mysql interface to know which are the slow queries. Depending on what slow queries you get you can add some indexes to the tables.