October 22, 2014

How to improve InnoDB performance by 55% for write-bound loads

During April’s Percona Live MySQL Conference and Expo 2014, I attended a talk on MySQL 5.7 performance an scalability given by Dimitri Kravtchuk, the Oracle MySQL benchmark specialist. He mentioned at some point that the InnoDB double write buffer was a real performance killer. For the ones that don’t know what the innodb double write […]

Testing Intel, Samsung & SanDisk SATA SSD

While working on the service architecture for one of our projects, I considered several SATA SSD options as the possible main storage for the data. The system will be quite write intensive, so the main interest is the write performance on capacities close to full-size storage. After some research I picked several candidates (I show […]

Is Synchronous Replication right for your app?

I talk with lot of people who are really interested in Percona XtraDB Cluster (PXC) and mostly they are interested in PXC as a high-availability solution.  But, what they tend not to think too much about is if moving from async to synchronous replication is right for their application or not. Facts about Galera replication […]

Comparing Percona XtraDB Cluster with Semi-Sync replication Cross-WAN

I have a customer who is considering Percona XtraDB Cluster (PXC) in a two colo WAN environment.  They wanted me to do a test comparing PXC against semi-synchronous replication to see how they stack up against each other. Test Environment The test environment included AWS EC2 nodes in US-East and US-West (Oregon).  The ping RTT latency […]

MLC SSD card lifetime and write amplification

As MLC-based SSD cards are raising popularity, there is also a raising concern how long it can survive. As we know, a MLC NAND module can handle 5,000-10,000 erasing cycles, after which it gets unusable. And obviously the SSD card based on MLC NAND has a limited lifetime. There is a lot of misconceptions and […]

InnoDB Flushing: a lot of memory and slow disk

You may have seen in the last couple of weekly news posts that Baron mentioned we are working on a new adaptive flushing algorithm in InnoDB. In fact, we already have three such algorithms in Percona Server (reflex, estimate, keep_average). Why do we need one more? Okay, first let me start by showing the current […]

SSD, XFS, LVM, fsync, write cache, barrier and lost transactions

We finally managed to get Intel X25-E SSD drive into our lab. I attached it to our Dell PowerEdge R900. The story making it running is worth separate mentioning – along with Intel X25-E I got HighPoint 2300 controller and CentOS 5.2 just could not start with two RAID controllers (Perc/6i and HighPoint 2300). The […]

How multiple disks can benefit for single client workload ?

Let us talk few more about disks. You might have read my previous post and Matt’s Reply and it looks like there are few more things to clarify and explain. Before I get to main topic of the article lets comment on IO vs Disk question. If you look at Disk Based databases all data […]

Innodb Double Write

One of very interesting techniques Innodb uses is technique called “doublewrite” It means Innodb will write data twice when it performs table space writes – writes to log files are done only once. So why doublewrite is needed ? It is needed to archive data safety in case of partial page writes. Innodb does not […]

Group commit and real fsync

During the recent months I’ve seen few cases of customers upgrading to MySQL 5.0 and having serious performance slow downs, up to 10 times in certain cases. What was the most surprising for them is the problem was hardware and even OS specific – it could show up with one OS version but not in […]