Question

I’ve optimized my queries and they all run faster than 0.6 seconds. However, sometimes they can take 2 or 3 seconds.

I’m using a shared server, however the server is only used by a static html site and my database. I’ve added functionality so I get an email if a query takes longer than 0.6 seconds. I get about 20 to 30 a day. The site gets around 800 hits a day. So the queries are ok most of the time.

I’m looking for a way in PHP using mysql that i can find out if I’m running other queries aka if the server is busy.

I want to add something in my php so I can add this to my slow query email

Any ideas ?

Answer 1

• Check the execution plan for those queries that do sometimes take long with EXPLAIN and see if you can rewrite them or add indexes to speed them up
• Make sure you’re flushing the query cache between tests, otherwise it could be the case that the queries are ALWAYS 2-3 seconds, you’re just getting cached results from the earlier run when you think it’s faster. The query is slow again when the cache is full or an update to the table invalidates the cached results.
• When you start getting mails about slow queries occurring, check the server load and memory usage. Maybe you’re running out of resources (cpu/memory/disk IO) when you receive a higher number of queries during some period of the day.

Regarding your update “I want to add something in my php so I can add this to my slow query email”:

• Run the query SHOW PROCESSLIST to get a list of all queries currently running. You can dump those results in your mail.
• Use exec or shell_exec to run top, uptime and other system commands that will give you an idea of the server’s state at the time of the slow queries. Save the output to a string and add it to your mails.