October 21, 2014

read_ahead (disabled) as steroid

Last week we were busy to align XtraDB performance with 5.4, now we have some results. Currently it is available as “hacks” to XtraDB (available on Lauchpad lp:~percona-dev/percona-xtradb/hacks-porting-tune if you are interested). Basically we took improvements from 5.4 and backported ones performance related to XtraDB. Here are results for tpcc-like workload, 100W (~10GB) ( raw […]

Can Innodb Read-Ahead reduce read performance ?

I ran into pretty interesting behavior today. We needed to dump and reload large database and we had pretty good IO subsystem so we started number of mysqldump processes in parallel. Unlike in other case when we did load in parallel, dump in parallel did not increase IO rate significantly and we could still see […]

LVM read performance during snapshots

For the same customer I am exploring ZFS for backups, the twin server is using regular LVM and XFS. On this twin, I have setup mylvmbackup for a more conservative backup approach. I quickly found some odd behaviors, the backup was taking much longer than what I was expecting. It is not the first time […]

btrfs – probably not ready yet

Every time I have a conversation on SSD, someone mentions btrfs filesystem. And usually it is colored as a solution that will solve all our problems, improve overall performance and SSD in particular, and it is a saviour. Of course it caught my curiosity and I decided to perform a benchmark similar to what I […]

Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5

This is the second blog post in the series of blog posts leading up to the talk comparing the optimizer enhancements in MySQL 5.6 and MariaDB 5.5. This blog post is aimed at the optimizer enhancement Multi Range Read (MRR). Its available in both MySQL 5.6 and MariaDB 5.5 Now let’s take a look at […]

Percona Server 5.6.13-60.5 third Release Candidate is now available

Percona is glad to announce the third Release Candidate of Percona Server 5.6.13-60.5 (downloads are available here and from the Percona Software Repositories). The final release is almost ready. Thank you to everyone who has been testing and filing bugs. You’ve been a big help and we can’t wait for you to see the fantastic […]

Is there room for more MySQL IO Optimization?

I prefer to run MySQL with innodb_flush_method=O_DIRECT in most cases – it makes sure there is no overhead of double buffering and I can save the limited amount of file system cache I would normally have on database server for those things which need to be cached — system files, binary log, FRM files, MySQL […]

Recovering Linux software RAID, RAID5 Array

Dealing with MySQL you might need to deal with RAID recovery every so often. Sometimes because of client lacking the proper backup or sometimes because recovering RAID might improve recovery, for example you might get point in time recovery while backup setup only takes you to the point where last binary log was backed up. […]

XtraDB storage engine release 1.0.2-3 (Spring edition) codename Sapporo

Today we announce release 1.0.2-3 of our XtraDB storage engine. Here is a list of enhancements: Move to MySQL 5.1.31 Scalability fix — ability to use several rollback segments Increasing the number of rseg may be helpful for CPU scale of write-intentional workloads. See benchmark results. Scalability fix — replaced page_hash mutex to page_hash read-write […]

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 […]