database size

So I thought I was having a database crisis, long story short it doesn't appear I am. I compared table sizes for my current installation and a two week old backup. A few tables seemed to drop in size which caught my eye and I'm not sure if I should be concerned or not. Left columns contain...

Kind of an odd question, but how big would you say an average single error log is? 1kb? Less? Does it ever auto purse? Does clearing the error log in the admincp automatically clear it in the database?