Intermittent problem with UTF-8 characters

Question

I am running a fairly standard LAMP stack.

The problem is an intermittent rendering of UTF-8 characters correctly. About 50% of the time the non-ASCII UTF-8 characters render correctly (e.g. with appropriate diacritical marks), but about 50% of the time I get the '?' rendition instead. If I reload the page, sometimes it corrects the problem and sometimes it does not. It happens with all browsers on all platforms, which suggests a MYSQL or Apache problem but I have not been able to figure it out.

The data base itself is in UTF-8 format and I have never seen the problem while browsing the database in phpMyAdmin.

I issue a SET NAMES utf-8 command upon opening the data base (and have tried changing that to a SET CHARSET utf-8 command) with no luck.

What's confusing me is that it is intermittent, happening in streaks, e.g. it will happen on 30 pages in a row (even if they are just reloads), and then clear up for 10 pages, and then happen again for a few pages, etc.

You can try to see the problem by hitting the 'list' button here: http://latin-words.com/list_vocab.php though it may take many reloads to either make it happen or make it go away

Server Configuration: Ubuntu: 9.10 Mysql: 5.1.37 PHP 5.2.10 Apache 2.2.12

Any hints would be greatly appreciated?

Answer 1

edit:
For searchers sake, from the comments, the problem was actually an issue doing a SET NAMES utf-8; (incorrect) instead of an SET NAMES utf8; (correct) That doesn't mean my much more obscure reason posted below cannot also be the reason ;)

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Sounds like a problem with locales & iconv, try to determine what locale is used in the webserver process the moment all is well, and the moment it doesn't work anymore (try $currentlocale = setlocale(LC_ALL,NULL); or $currentlocale = setlocale(LC_CTYPE ,NULL); to get the used locale).