Late at night, in server rooms, if you listen carefully, you can hear how databases quietly cry. But why? We as developers often see databases as magic boxes which work fast and without the expense of resources. Databases are far from ideal, they are just abstractions of many algorithms that interact with each other and a little understanding of what is happening "under the bonnet" can prevent common performance problems.
In this talk, Mikhail will tell about common mistakes in work with RDBMS and NoSQL databases, how they affect performance, why they happen and how to reduce or prevent their effect.