I added this bits to the part of the code where the SQL error appears:
$backtrace = "SQL error on request: " . $sql . "\nBacktrace:\n" . get_backtrace();
mail ( 'engerim@forumosa.com', 'SQL error on Forumosa', $backtrace);
I also increased the number of maximum connections on Wednesday.
So in case this happens again we’ll get immediately informed.
The server has been stable since the upgrade. Forumosa had a few out of memory errors before, not now anymore.
I guess the main reason is that the database is huge. You can go back in nearly 13 years of posts.
The oldest one: Oriented.org - Viewer Comments and Feedback
The posts table alone is about 1.1 GB. Totally we have 2.4 GB of pure text data.
This isn’t ‘just’ an average phpbb installation, For the “user experience” I take it that it is being worked on.