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How small changes impact complex systems – MySQL example

If you’ve been studying complex systems you know what minor changes might cause consequences of much greater proportions, sometimes causing some effects that are not easily explained at first. I recently ran across a great …


InnoDB crash recovery speed in MySQL 5.6

It has been a while since I have looked at InnoDB crash recovery. A lot has change in the last few years – we have serious crash recovery performance improvements in MySQL 5.5 and MySQL …


Making HAProxy 1.5 replication lag aware in MySQL

HAProxy is frequently used as a software load balancer in the MySQL world. Peter Boros, in a past post, explained how to set it up with Percona XtraDB Cluster (PXC) so that it only sends queries …


Sys Schema for MySQL 5.6 and MySQL 5.7

Performance Schema (P_S) has been available since MySQL 5.5, more than 4 years ago. It is still difficult to see production servers with P_S enabled, even with MySQL 5.6 where the feature is enabled by …


MySQL upgrade best practices

MySQL upgrades are necessary tasks and we field a variety of questions here at Percona Support regarding MySQL upgrade best practices. This post highlights recommended ways to upgrade MySQL in different scenarios. Why are MySQL …


When (and how) to move an InnoDB table outside the shared tablespace

In my last post, “A closer look at the MySQL ibdata1 disk space issue and big tables,” I looked at the growing ibdata1 problem under the perspective of having big tables residing inside the so-called shared …


Getting to know TokuDB for MySQL

During last April’s Percona Live MySQL Conference and Expo, TokuDB celebrated it’s first full-year as an open source storage engine. I still remember reading the official announcement and the expectations it created one year ago. The …


Why TokuMX Changed MongoDB’s Oplog Format for Operations

Over several posts, I’ve explained the differences between TokuMX replication and MongoDB replication, and why they are completely incompatible. In this (belated) post, I explain one last difference: the oplog format for operations. Specifically, TokuMX …


Introducing Partitioned Collections for MongoDB Applications

TokuMX 1.5 is around the corner. The big feature will be something we discussed briefly when talking about replication changes in 1.4: partitioned collections. Before introducing the feature, I wanted to mention the following. Although …


On TokuMX Oplog, Tailable Cursors, and Concurrency

In a post last week, I described the difference in concurrency behavior between MongoDB’s oplog and TokuMX’s oplog. In short, here are the key differences: MongoDB protects access to the oplog with a database level …