It seems these days if anyone knows anything about tuning InnoDB, it’s that you MUST tune your innodb_buffer_pool_size to 80% of your physical memory. This is such prolific tuning advice, it seems engrained in many a DBA’s mind. The MySQL manual to this day refers to this rule, so who can blame the DBA? The […]
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I often talk with people who are very interested in the features of Percona XtraDB Cluster (PXC) such as synchronous and parallel replication, multi-node writing and high availability. However some get confused when operating a real PXC cluster because they do not fully realize the implications of these features. So here is a fun way […]
A few years back Deva wrote about how to use tcpdump on very busy hosts. That post sparked my interest about exploring how to measure the impact of tcpdump on very busy hosts. In this post, I wanted to highlight how much of an impact there really is and what options you have to make the […]
Every day hundreds of millions of dollars are wasted by allowing improperly tuned or misconfigured systems, misunderstood infrastructure, and inefficient IT operations to live and thrive in data centers around the globe. There are both direct and indirect costs associated with allowing these unhealthy systems to continue to exist. Let’s look at some. The setup: […]
The MySQL Performance Schema exposes so much data that it’s not trivial to learn, configure, and use. With recently released Percona Agent 1.0.11 you can get query metrics – like min, max, and average query execution time – with a few clicks: Click “Apply” and about two minutes later you’ll have query metrics from Performance Schema, collected and […]
If you use Percona Server 5.5 and you have configured it to use multiple buffer pool instances than sooner or later you’ll see the following lines on the server’s error log and chances are you’ll be worried about them:
InnoDB: detected cycle in LRU for buffer pool 5, skipping to next buffer pool.
InnoDB: detected cycle in LRU for buffer pool 3, skipping to next buffer pool.
InnoDB: detected cycle in LRU for buffer pool 7, skipping to next buffer pool.
Worry not as this is mostly harmless. It’s becoming a February tradition for me (Fernando) […]
This is yet another story of Django web-framework with time zone support and pain dealing with python datetimes and MySQL on the backend. In other words, offset-naive vs offset-aware datetimes. Shortly, more about the problem. After reading the official documentation about the time zones, it makes clear that in order to reflect python datetime in […]
Have you ever experienced a situation where one moment you can connect to the MySQL database and the next moment you cannot, only to be able to connect again a second later? As you may know one cannot open infinite connections with MySQL. There’s a practical limit and more often than not it is imposed […]
One new feature in Percona XtraDB Cluster (PXC) in recent releases was the inclusion of the ability for an existing cluster to auto-bootstrap after an all-node-down event. Suppose you lose power on all nodes simultaneously or something else similar happens to your cluster. Traditionally, this meant manually re-bootstrapping the cluster, but not any more. How it […]
Often enough I find MySQL benchmark results where the difference between results is 1% or even less and some conclusions are drawn. Now it is not that 1% is not important – especially when you’re developing the product you should care about those 1% improvements or regressions because they tend to add up. However with […]