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Displaying posts with tag: mariadb (reset)
MariaDB MaxScale Masking Basics and Examples

I wanted to take a moment to write up a post on MariaDB MaxScale’s masking basics and include some real-world examples.

We have nice documentation on the subject, and Dipti wrote a nice blog post on it as well. I just wanted to provide my take on it, and hopefully build upon what is already there and offer some additional insights.

To provide a 50-foot overview, the masking filter makes it possible to obfuscate the returned value of a particular column.

3 quite common columns where this would be very beneficial: Social Security Number (“SSN”), Date of Birth (“DOB”), and Credit Card Number (“CCNUM”).

To use masking, it assumes you already have a MaxScale service up and running. For instance, the readwrite …

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Fun with Bugs #79 - On MySQL Bug Reports I am Subscribed to, Part XV

More than 3 weeks passed since my previous review of public MySQL bug reports I am subscribed to, so it's time to present some of the bugs I've considered interesting in January, 2019.

As usual, I'll review them starting from the oldest and try to summarize my feelings about these bugs at the end of this post. Here they are:

  • Bug #93806 - "Document error about ON DUPLICATE KEY UPDATE". Years pass, but fine MySQL manual still does not explain some cases of InnoDB locking properly. Xiaobin Lin found yet another case that it does not explain properly. Or, maybe, the manual is correct and the problem in …
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Debugging MariaDB Galera Cluster SST Problems – A Tale of a Funny Experience

Recently, I had to work on an emergency for a customer who was having a problem restarting a MariaDB Galera Cluster. After a failure in the cluster they decided to restart the cluster entirely following the right path: bootstrapping the first node, and then adding the rest of the members, one by one. Everything went fine until one of the nodes rejected the request to join the cluster.

Given this problem, the customer decided to ask us to help with the problematic node because none of the tests they did worked, and the same symptom repeated over and over: SST started, copied few gigs of data and then it just hanged (apparently) while the node remained out of the cluster.

Identifying the issue…

Once onboard with the issue, initially I just checked that the cluster was trying a SST: given the whole dataset was about 31GB I decided to go directly to a healthy solution: to clean up the whole datadir and start afresh. No luck …

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On my Favorite FOSDEM 2019 MySQL, MariaDB and Friends Devroom Talks

This year I had not only spoken about MySQL bugs reporting at FOSDEM, but spent almost the entire day listening at MySQL, MariaDB and Friends Devroom. I missed only one talk, on ProxySQL, (to get some water, drink a bottle of famous Belgian beer and chat with my former colleague in MySQL support team, Geert, whom I had not seen for a decade). So, for the first time out of my 4 FOSDEM visits I've got a first hand impression about the entire set of talks in the devroom that I want to share today, while I still remember my feelings.

Most of the talks have both slides and videos …

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Chris Attending OpenWorks19

Those of you who know me know that I don’t travel often.

So it’s kind of a big deal, at least for me, that I will be at OpenWorks in NYC later this month!!!

If you’re planning on attending, please stop by and say “hi”! I’ll be helping in the Security Workshop on Monday, or you can find me at one of the Expert Bars Tuesday and Wednesday.

If you’re on the fence about attending, please message (or email) me for a significant discount code (if that might help you decide or help persuade your manager!).

Anyway, I’m excited to be going, and I hope to see you there!

MariaDB OpenWorks

Dates: February 25th – February 27th

A New Dashboard to Monitor Memory Usage in the PMM plugin!

While the PMM team works hard on our PMM 2.0 release, we have been working on a few things in the background which we’d like to show off !  In particular we have developed a new dashboard that displays metrics related to memory usage on Linux systems. The dashboard leverages information collected by node_exporter. The graphs take advantage of  /proc filesystem files, specifically:

  • meminfo: Provides information about distribution and utilization of memory. This varies by architecture and compile options.
  • vmstat: Provides information about block IO and CPU activity in addition to memory.

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Viewing the Originating Host or IP Address with MaxScale’s Proxy Protocol

If you use MaxScale to route queries from various servers to some MariaDB server(s), when viewing the processlist on the MariaDB server, you will see MaxScale’s host for any “host” information related to that connection or its queries.

When tracking down problematic queries, it can be helpful to know what originating host of that query.

MaxScale’s proxy protocol to the rescue.

The proxy protocol was introduced in MaxScale 2.2 and MariaDB 10.3.

To enable it, it is quite simple (essentially just 2 changes).

1. In MariaDB, you need to set the variable proxy_protocol_networks in your my.cnf file (you can specify comma-separated IP addresses and/or subnetworks, as well as localhost and ::1):

proxy-protocol-networks=::1,, localhost

This one, which I will use as-is, is the example from the …

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FOSDEM MySQL Community Dinner – Friday 1 Feb 2019 – Tickets Selling Out Fast!

If you have not purchased your ticket yet for this years FOSDEM MySQL, MariaDB and Friends Community Dinner, hurry! We’ve already sold 2/3 of our tickets since launching tickets sales last week.

The dinner takes place in the same location, on the same day as the  pre-FOSDEM MySQL Day 2019.

Buy your tickets on Eventbrite:

We’re looking forward to meeting you all again at Fosdem and the Community Dinner. See you then! Party-Squad – Kenny Gryp,  …

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Will IO Size Affect your RDS Performance?​

During our recent consulting with one of our client, We came across an interesting issue on RDS. The baseline is that “Low IO size on your RDS instance can affect your DB performance”.  Yes, It’s IO size, Not IOPS.

We had our production systems running on RDS MySQL with a single master, 3 replicas. All instances are of same type db.m4.4xlarge with same parameter group configuration and the disk size is 1.5 TB. According to the AWS user guide, each of these instances can support up to 4500 (sustained IOPS) guaranteed IOPS.

Find below the Write IOPS graph for all the instances.

It’s understood that Write IOPS / pattern on Master can vary when compared with Slave, due to a lot of factors like binlog row format, log writing etc. But it has to be almost similar for all the slaves given that it …

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Replication Manager Works with MariaDB

Some time ago I wrote a script to manage asynchronous replication links between Percona XtraDB clusters. The original post can be found here. The script worked well with Percona XtraDB Cluster but it wasn’t working well with MariaDB®.  Finally, the replication manager works with MariaDB.

First, let’s review the purpose of the script. Managing replication links between Galera based clusters is a tedious task. There are many potential slaves and many potential masters. Furthermore, each replication link must have only a single slave. Just try to imagine how you would maintain the following replication topology:

A complex replication topology

The above topology consists of five clusters and four …

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