What are the tools for debugging database queries?

Question

Database

We set the task of optimizing a self-written site in PHP. It works slowly and I suspect that the issue here is in queries to the database. Please tell me the tools with which they can be tracked, for example, as in Yii2:

Answer 1

From the DBMS side:
Postgresql: pg_stat_statements
https://www.postgresql.org/docs/current/static/pgs...
Mysql: slow query log
dev.mysql.com/doc/refman/5.7/en/slow-query- log.html
For others, they don’t know, well, since even mysql has at least something, then others will definitely have something.
From the PHP side - xdebug + kcachegrind will tell you exactly where you are wasting time for a particular request and how you got there. To monitor the combat system as a whole, look towards pinba.
From the project code itself - the subd access libraries are not directly involved in profiling. Therefore, you need to look at a specific project, is there a place where you can stick query profiling.