I’ve been talking and writing a bit lately about the scaling problems I’m seeing on fast servers running lots of queries. As a rough guide, I’m seeing this in servers running 20k queries per second and higher, lots of memory, lots of CPU cores, and most queries are running faster than one millisecond; some in [...]
I have not caused a fist fight in a while, so it’s time to take off the gloves. I claim that somewhere around of 99% of advice about tuning MySQL’s key cache hit ratio is wrong, even when you hear it from experts. There are two major problems with the key buffer hit ratio, and [...]
You know how in addition to the main movie you have extras on the DVD.Â Extra commentary, bloopers, extra scenes, etc? Well welcome the Tyrant extras.Â With my previous blog posts I was trying to set-up a case for looking at NOSQL tools, and not meant to be a decision making tool.Â Each solution has [...]
This is part 3 of our series.Â In part 1 we talked about boosting performance with memcached on top of MySQL, in Part 2 we talked about running 100% outside the data with memcached, and now in Part 3 we are going to look at a possible solution to free you from the database.Â The [...]
Have you ever wondered how optimized your Memcached installation is? There is a common misconception that one doesn’t have to think too deeply about Memcached performance, but that is not true. If your setup is inefficient, you could: Burn Memory Waste Network Round-Trips Store Keys That Never Get Retrieved Have a Low Cache Hit Ratio [...]
I vaguely recall a couple of blog posts recently asking something like “what’s the formula to compute mysqld’s worst-case maximum memory usage?” Various formulas are in wide use, but none of them is fully correct. Here’s why: you can’t write an equation for it.
One of my favorite MySQL configurations for high availability is master-master replication, which is just like normal master-slave replication except that you can fail over in both directions. Aside from MySQL Cluster, which is more special-purpose, this is probably the best general-purpose way to get fast failover and a bunch of other benefits (non-blocking ALTER [...]
Our customers or prospective customers often ask us how we do a performance audit (it’s our most popular service). I thought I should write a blog post that will both answer their question, so I can just reply “read all about it at this URL” and share our methodology with readers a little bit. This [...]