My website has been chewing through disk space recently. I couldn’t work out why and the largest files a few weeks ago were some webstat logs, so I cleared them down. Tonight, as I couldn’t upload anything (or apply any updates) I hunted around and found a couple of error_log files in my webspace.  The first related to a PHP file that was reading my Twitter feed using an old API and so was repeatedly failing. I removed the log and the offending PHP but that wasn’t the biggest problem. In my blog’s home folder was a 1.2GB error_log file – loo big to even read properly in Notepad, Word, or anything else I tried.

I managed to download a partial copy of the file (using Filezilla, then cancelling the transfer after a few seconds and saw lots of lines that contained the following error:

WordPress database error Column ‘offset’ cannot be null for query INSERT INTO wp_wpb2d_processed_files (file, uploadid, offset)

That told me it was the (very useful) WordPress Backup to Dropbox plugin, by Michael de Wildt. I don’t really want to disable that but luckily I found a fix on WordPress.org, posted by Rich Helms:

The issue is file wordpress-backup-to-dropbox/Classes/Processed/Files.php

Toward the bottom of the program change from

$this->upsert(array(
'file' => $file,
'uploadid' => null,
'offset' => null,
));

to

$this->upsert(array(
'file' => $file,
'uploadid' => null,
'offset' => 0,
));

so change the offset default from null to 0 and the issue goes away

Sure enough, that change seems to have fixed the problem and whilst the edit to the plugin will be over-written with the next release, hopefully that release will also include a permanent fix!