This script will massconvert all tables to UTF-8 (needed from Confluence 5.3 and onwards):
#!/bin/bash
all_tables=$(mysql -uconfluence -pxxxxxxxx confluence -e 'show tables')
for table in ${all_tables}; do
echo "Altering ${table}"
echo "ALTER TABLE confluence.${table} convert to character set utf8 collate utf8_bin" > /tmp/sql
mysql -uconfluence -pxxxxxxxx confluence < /tmp/sql
done