I'm having an issue with my search index on both 4.6.10 and 4.7.4. The problem that I'm seeing is that some content is being indexed and others is not and I can't figure out what the difference is. I'm using the built in search facilities.

My website is basically a set of pages with links to external content which I have found interesting. Each page follows the same basic format with the links and comments about them stored in a table, so it is a little surprising that the index results are inconsistent. It doesn't appear to be related to the case of the search text, nor does it seem to be related to the length of the keywords either.

The cron logs don't seem to be showing anything so no help there. Has anyone come across this or a similar problem and solved it? Is it possible that one of the other search modules would be more appropriate? If so, which one(s) and why?

I apologise for the vagueness of the post, but I don't have much more to go on.

Thanks in advance for any assistance.