The latest from the MySQL community

This post was written by Seppo Jaakola, CEO of Codership.

There appears to be great misunderstanding as to what MySQL transaction isolation levels Galera CLuster actually supports and how. This blog post tries to give answer to those uncertainties.

Galera Cluster provides SNAPSHOT ISOLATION between transactions running on separate cluster nodes. Transactions running on the same node are isolated by whatever was configured as the transaction isolation level in the MySQL configuration. So, if you have configured the default REPEATABLE READ isolation, transactions issued on the same node will behave under REPEATABLE READ semantics. However, for transactions issued on separate cluster nodes, the ‘first committer wins’ rule of SNAPSHOT ISOLATION is provided, and this will fix the lost update problem that generally hurts REPEATABLE READ isolation.

Therefore, it is not safe for the application to rely on SNAPSHOT …

I installed the MariaDB 10.1 Release Candidate. Nothing interesting happened, which from MariaDB's point of view is good. But here's how I tried to make it interesting. Some of this applies to late releases of MariaDB 10.0 as well.

Loop with MAKE INSTALL

My habit is to download the source to directory X and then say "cmake -DCMAKE_INSTALL_PREFIX=/X" (the same directory), then "make", then "make install". That doesn't work any more. Now I can't install in the same directory that I downloaded in. Not a big deal; perhaps I'm the only person who had this habit.

Crash with ALTER

In an earlier blog post General Purpose Storage Engines in MariaDB I mentioned a crash, which I'm happy to say is fixed now. Here's another way to crash, once again involving different storage engines.

Welcome to the …

On Monday 21 September Percona Live will start in Amsterdam.

The program is full of interesting topics and I am sure a lot of great discussions will follow.

I whish all my best to all my colleagues, friends and customers that will attend it. Have fun guys and drink a couple of beer for me as well.

That is it, I had decided to do not submit speech(es) and to do not come this year, not only to Percona Live but to most or all the conferences.

I want to stay focus on my customers for now, and be present as much as I can for my teammates.

We have so much going on that an effort in that direction must be done, and the few time left ... well I have to read a lot of intersting stuff not Tech related.

So have fun, learn, teach, listen and talk ... but on top of all share and …

On Monday 21 September Percona Live will start in Amsterdam.

The program is full of interesting topics and I am sure a lot of great discussions will follow.

I whish all my best to all my colleagues, friends and customers that will attend it. Have fun guys and drink a couple of beer for me as well.

That is it, I had decided to do not submit speech(es) and to do not come this year, not only to Percona Live but to most or all the conferences.

I want to stay focus on my customers for now, and be present as much as I can for my teammates.

We have so much going on that an effort in that direction must be done, and the few time left ... well I have to read a lot of intersting stuff not Tech related.

So have fun, learn, teach, listen and talk ... but on top of all share and …

The MySQL team are busily working on improving ways to use MySQL in scalable highly available systems. As most of you are already aware, the MySQL Group Replication project is progressing at full speed. Indeed, we just got preview release 0.5 out, while Fabric 1.5.6 was just released and work is ongoing for the Fabric 1.6 release.…

There are at least three issues with the catalog URL rewrite indexer and URL rewrite management in Magento:

• A reindex will add a new rows for products with duplicate url_key's - every single time you reindex
• Disabled products generate new rows
• Products that are not-visible individually generate new rows

Core bug

I’m pretty late to the party, but decided to investigate it anyway since I have to deal with many stores whose indexers get stuck because of various SQL errors related to the URL rewrite index and whose tables are way too big and out of proportions for the amount of categories and products they have.

This bug will make your table grow into the millions of rows and hundreds of …

[…] Aurora CPU […]

This Log Buffer Edition dives deep into the ocean of blogosphere and surfaces with some cool blog posts from Oracle, SQL Server and MySQL.

Oracle:

• Lets Talk DB Perth
• The Fundamental Challenge of Computer System Performance
• Index Advanced Compression: Multi-Column Index
• Middleware Diagnostics Advisor (MDA) Setup
• Most people are now aware that in 12c, a …

Intro

The purpose of this project was to measure the potential overhead of VividCortex Agent, which is used by VividCortex.com database monitoring system. This benchmark is part of a consulting engagement with VividCortex and paid by the customer.

The assumption is that VividCortex agent uses CPU processing time, and we should see an impact on user queries when the workload is CPU-intensive (how much is to be measured). The impact on IO-bound should be small or insignificant.

Workload Description
For this, we use LinkBenchX benchmark in a combination of different options.

Workloads

There are 3 different workloads we want to look into:

• CPU bound. …

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