Showing entries 31 to 40 of 193
« 10 Newer Entries | 10 Older Entries »
Displaying posts with tag: galera (reset)
Log Buffer #435: A Carnival of the Vanities for DBAs

Sun of database technologies is shining through the cloud technology. Oracle, SQL Server, MySQL and various other databases are bringing forth some nifty offerings and this Log Buffer Edition covers some of them.

Oracle:

  • How to create your own Oracle database merge patch.
  • Finally the work of a database designer will be recognized! Oracle has announced the Oracle Database Developer Choice Awards.
  • Oracle Documents Cloud Service R4: Why You Should Seriously Consider It for Your Enterprise.
  • Mixing Servers in a Server …
[Read more]
Bypassing SST in Percona XtraDB Cluster with binary logs

In my previous post, I used incremental backups in Percona XtraBackup as a method for rebuilding a Percona XtraDB Cluster (PXC) node without triggering an actual SST. Practically this reproduces the SST steps, but it can be handy if you already had backups available to use.

In this post, I want to present another methodology for this that also uses a full backup, but instead of incrementals uses any binary logs that the cluster may be producing.

Binary logs on PXC

Binary logs are not strictly needed in PXC for replication, but …

[Read more]
Bypassing SST in Percona XtraDB Cluster with incremental backups

Beware the SST

In Percona XtraDB Cluster (PXC) I often run across users who are fearful of SSTs on their clusters. I’ve always maintained that if you can’t cope with a SST, PXC may not be right for you, but that doesn’t change the fact that SSTs with multiple Terabytes of data can be quite costly.

SST, by current definition, is a full backup of a Donor to Joiner.  The most popular method is Percona XtraBackup, so we’re talking about a donor node that must:

  1. Run a full XtraBackup that reads its entire datadir
  2. Keep up with Galera replication to it as much as possible (though laggy donors don’t send flow control)
  3. Possibly still be serving application traffic if you don’t remove Donors from rotation.
[Read more]
MariaDB Galera Cluster 5.5.44 and 10.0.20 now available

The MariaDB project is pleased to announce the immediate availability of MariaDB Galera Cluster 10.0.20 and MariaDB Galera Cluster 5.5.44. These are Stable (GA) releases.

Download MariaDB Galera Cluster 10.0.20

Release Notes Changelog What is MariaDB Galera Cluster?

Download …

[Read more]
Optimizing Percona XtraDB Cluster for write hotspots

Some applications have a heavy write workload on a few records – for instance when incrementing a global counter: this is called a write hotspot. Because you cannot update the same row simultaneously from multiple threads, this can lead to performance degradation. When using Percona XtraDB Cluster (PXC), some users try to solve this specific issue by writing on multiple nodes at the same time. Good idea or bad idea? Read on!

Simultaneous writes on a standalone InnoDB server

Say you have these 3 transactions being run simultaneously (id is the primary key of the table):

# T1
UPDATE t SET ... WHERE id = 100
# T2
UPDATE t SET ... WHERE id = 100
# T3
UPDATE t SET ... WHERE id = 101

All transactions will require a row lock on the record they want to modify. So T3 can commit at the same time than T1 and/or T2, because it will …

[Read more]
Is 80% of RAM how you should tune your innodb_buffer_pool_size?

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 question is: does it makes sense?

What uses the memory on your server?

Before we question such advice, let’s consider what can take up RAM in a typical MySQL server in their broad categories.  This list isn’t necessarily complete, but I think it outlines the large areas a MySQL server could consume memory.

  • OS Usage: Kernel, running processes, filesystem cache, etc.
  • MySQL fixed usage: query cache, InnoDB …
[Read more]
Test your knowledge: Percona XtraDB Cluster (PXC) quiz

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 to test your PXC knowledge: try to solve these 12 questions related to PXC! (you will find the answers at the end of the post.)

Workload

1. With Galera 3.x, support for MyISAM is experimental. When can we expect to have full MyISAM support?
a. This will never happen as Galera is designed for transactional storage engines.
b. This is planned for Galera 4.0.

2. Why aren’t all workloads a good fit for PXC?
a. Execution plans can change compared to a regular MySQL server, so performance is sometimes not as good as with a regular MySQL server.
b. Large …

[Read more]
Q&A: Multi-threaded Replication in MySQL 5.6 and MySQL 5.7

My webinar “Multi-threaded Replication in MySQL 5.6 and 5.7″ on February 25 generated several excellent questions following the presentation (available here for playback along with the slides). I didn’t have time to answer many of the questions during the session and so in this post I answer all of them. Thanks to everyone who attended!

Q: What do you expect from MTS with logical clock? Do you think performance would be good as with per database?
A: MTS with 5.6 is not usable if you have a single database. I do not have numbers, but this is quite frequent. With 5.7 everyone should be able to benefit from multi-threaded replication.

Q: When MySQL 5.6 was released, performance of MTS was lower, than in 5.5, for example. Is this addressed now?
A: I am not sure which …

[Read more]
Galera for Mesos

This time it is nothing like a linkt to another Blog:  Galera on Mesos

Ok as a fact I was kinda involved. Even the work is done by Stefan all alone. We meat for a day in a coworking space and discussed about Galera and Mesos.
In the end Stefan produced this incredible blogpost and pushed Mesos forward.
Whats the fun about this post?
We already now Galera is already the standard in a lot of architectures. For example OpenStack. Doing consultant work for Docker also I encourage to use Galera for all this infrastructures Docker runs on. 
Mesos is about to run easy on 1000 nodes. It has a nice abstraction of nodes and framework. Companies like Airbnb, Paypal, eBay, Groupon use Mesos. Having a Galera poc for Mesos is going to make it likely to …

[Read more]
MariaDB Galera Cluster 10.0.16 now available

Download MariaDB Galera Cluster 10.0.16

Release Notes Changelog What is MariaDB Galera Cluster?

MariaDB APT and YUM Repository Configuration Generator

The MariaDB project is pleased to announce the immediate availability of MariaDB Galera Cluster 10.0.16. This is a Stable (GA) release.

See the …

[Read more]
Showing entries 31 to 40 of 193
« 10 Newer Entries | 10 Older Entries »