Search Results for: default storage engine innodb mysql

Using Cgroups to Limit MySQL and MongoDB memory usage

Quite often, especially for benchmarks, I am trying to limit available memory for a database server (usually for MySQL, but recently for MongoDB also). This is usually needed to test database performance in scenarios with different memory limits. I have physical servers with the usually high amount of memory (128GB or more), but I am […]

Update on the InnoDB double-write buffer and EXT4 transactions

In a post, written a few months ago, I found that using EXT4 transactions with the “data=journal” mount option, improves the write performance significantly, by 55%, without putting data at risk. Many people commented on the post mentioning they were not able to reproduce the results and thus, I decided to further investigate in order […]

MySQL 5.7 key features

The other day I was discussing new features of MySQL 5.7 with a Percona Support customer. After that conversation, I thought it would be a good idea to compile list of important features of MySQL 5.7. The latest MySQL 5.7.6 release candidate (RC) is out and is packed with nice features. Here’s a list of […]

Illustrating Primary Key models in InnoDB and their impact on disk usage

On a recent engagement I worked with a customer who makes extensive use of UUID() values for their Primary Key and stores it as char(36), and their row count on this example table has grown to over 1 billion rows. The table is INSERT-only (no UPDATEs or DELETEs), and the bulk of their retrieval are PK […]

Worrying about the ‘InnoDB: detected cycle in LRU for buffer pool (…)’ message?

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:

Worry not as this is mostly harmless. It’s becoming a February tradition for me (Fernando) […]

Is MySQL’s innodb_file_per_table slowing you down?

MySQL’s innodb_file_per_table is a wonderful thing – most of the time. Having every table use its own .ibd file allows you to easily reclaim space when dropping or truncating tables. But in some use cases, it may cause significant performance issues. Many of you in the audience are responsible for running automated tests on your […]

Recover MySQL root password without restarting MySQL (no downtime!)

Disclaimer: Do this at your own risk! It doesn’t apply if you’re using Pluggable authentication and certainly won’t be usable if/when MySQL system tables are stored on InnoDB What is the situation? The situation is the classic “need to recover MySQL root password” but you cannot restart MySQL (because it is the master production server, […]

Google Compute Engine adds Percona XtraDB Cluster to click-to-deploy process

I’m happy to announce that Google has added Click-to-deploy functionality for Percona XtraDB Cluster (PXC) on Google Cloud Compute nodes. This gives you the ability to rapidly spin up a cluster for experimentation, performance testing, or even production use on Google Compute Engine virtual machines. What is Percona XtraDB Cluster? Percona XtraDB Cluster is a […]

Avoiding MySQL ALTER table downtime

MySQL table alterations can interrupt production traffic causing bad customer experience or in worst cases, loss of revenue. Not all DBAs, developers, syadmins know MySQL well enough to avoid this pitfall. DBAs usually encounter these kinds of production interruptions when working with upgrade scripts that touch both application and database or if an inexperienced admin/dev […]

Innodb transaction history often hides dangerous ‘debt’

In many write-intensive workloads Innodb/XtraDB storage engines you may see hidden and dangerous “debt” being accumulated – unpurged transaction “history” which if not kept in check over time will cause serve performance regression or will take all free space and cause an outage. Let’s talk about where it comes from and what can you do […]