mariadb - Slow SQL Query with Federated engine

Question

My set up is the following:

• website running both the php code and the mariaDB 10.2 dabatase
• local "Master" database under mariaDB 5.3 with 100MB/s internet connection where I need to have synchronous updates (inputs can be made on both ends)

Running simple queries like

select * from table

Takes ages (more than 45s).

When I look at processor and RAM usage, both are low (3% and 7% respectively at most).

The traffic takes this shape when I run a query:

My questions are then:

• Is the latency normal in those cases when tables are linked by the Federated engine or is there something wrong ?
• Why the query pulls around 150KB/s for 30 seconds and then finally jumps to some decent bandwith.
• Are there some generic configurations to be made to speed up the queries ? (ex: identical mariaDB versions)

Thanks much for your help !!

question from:https://stackoverflow.com/questions/65937481/slow-sql-query-with-federated-engine

Answer 1

Waitting for answers