Settings for parallel replication workers

We currently (2018/04) run several MySQL 5.7.25 replicas with parallel replication workers. Over time there were huge changes in load on replicas so I had to adjust settings several times to keep up with changes and correct always newly occurring replication lags. So...

How to clean or resize the ibtmp1 file in MySQL

Based on “How to clean or resize the ibtmp1 file in MySQL?” This is another lesson learned in rather “hard way” – temporary tablespace on one of our instances grew so big we had problems with full disk. Fortunately both Debian and MySQL...

Check MySQL slow log from command line

MySQL slow log is extremely useful feature of MySQL server. But its investigation can be very painful. Mainly due to the usually huge size of it. Investigation using command line tools is usually the quickest possibility. So here are few useful commands: find longest...