Question

So I was wondering whether I should or should not ping the mysql server (mysqli_ping) to ensure that the server is always alive before running query?

Answer 1

You shouldn’t ping MySQL before a query for three reasons:

1. Its not a reliable way of checking the server will be up when you attempt to execute your query, it could very well go down in the time between the ping response and query.
2. Your query may fail even if the server is up.
3. As the amount traffic to your website scales up, you will be adding a lot of extra overhead to the database. Its not uncommon in enterprise apps that have used this method to see a huge amount of the database’s resources getting wasted on pings.

The best way to deal with database connections is error handling (try/catch), retries and transactions.

More on this on the MySQL performance blog:
Checking for a live database connection considered harmful

In that blog post you’ll see 73% of the load on that instance of MySQL was caused by applications checking if the DB was up.