In this blog, we’ll discuss the ramifications of the Galera Error Failed to Report Last Committed (Interrupted System Call).

I have recently seen this error with Percona XtraDB Cluster (or Galera):

[Warning] WSREP: Failed to report last committed 549684236, -4 (Interrupted system call)

It was posted in launchpad as a bug in 2013: https://bugs.launchpad.net/percona-xtradb-cluster/+bug/1434646

My colleague Przemek replied, and explained it as:

Reporting the last committed transaction is just a part of the certification index purge process. In case it fails for some reason (it occasionally does), the cert index purge may be a little delayed. But it does not mean the transaction was not applied successfully. This is a warning after all.

If we look up this error in the source code, we realize …

In this blog, we will discuss MySQL 5.7 asynchronous query execution using the X Plugin.

Overview

MySQL 5.7 supports X Plugin / X Protocol, which allows (if the library supports it) asynchronous query execution. In 2014, I published a blog on how to increase a slow query performance with the parallel query execution. There, I created a prototype in the bash shell. Here, I’ve tried a similar idea with NodeJS + mysqlx library (which uses MySQL X Plugin).

TL;DR version: By using the MySQL X Plugin with NodeJS I was able to increase query performance 10x (some query rewrite required).

X Protocol and NodeJS

Here are the steps required:

1. First, we will need to …

I was speaking at PHP[Tek] this week on the JSON Data Type and using generated columns. JSON columns can not be indexed but data from a JSON column can be extracted via a generated column and that column can be indexed. All was going well until someone asked me about modifying data in a generated column. Was it possible?

I blinked hard. I have not tried that! I had not seen any mention of that in the documentation. So I had to admit that I did not know and would have to try that.

The Test

mysql> CREATE TABLE gentest (a INT, b INT AS (a + 1) STORED, INDEX(b));
...
mysql> INSERT INTO gentest VALUES (1),(2),(3),(4);
...

So now we have a table with data to test. So lets try to modify the value of one of the generated columns.

mysql> UPDATE gentest SET b = 9 WHERE a = 1;

And what did …

This article consolidates information from several sources into the format I use to setup MySQL Master/Master Replication. The beauty of Linux and open source is that there are many different ways to do this. Please take a look at my references and use them to accommodate any needs you may have.

Awhile ago I found myself analyzing a MySQL fabric installation to understand why a group member was occasionally being marked as FAULTY even when the server was up and running and no failures were observed.  

         
                         server_uuid     address  status       mode weight
------------------------------------ ----------- ------- ---------- ------
ab0b0653-6121-11c5-55a0-007543445454 mysql1:3306 PRIMARY READ_WRITE    1.0
f34dd331-2432-11f4-a2d3-006754678533 mysql2:3306 FAULTY  READ_ONLY     1.0

Upon reviewing mysqlfabric logs, I found the following warnings were being logged from time to time:

[WARNING] 1442221217.920115 - FailureDetector(xc_grp_1) - Server (f34dd331-2432-11f4-a2d3-006754678533) in group (xc_grp_1) is unreachable

Since I was not clear under which circumstances a server is marked as FAULTY, I decided to review MySQL Fabric code (Python) to better …

Some time ago, I published the article on AWS Aurora Benchmarking (AWS Aurora Benchmarking – Blast or Splash?), in which I analyzed the behavior of different solutions using synchronous replication in AWS environment. This blog follows up with some of the comments and suggestions I received regarding that post from the community and Amazon engineers.

I decided to perform another round of tests, keeping in mind comments and suggestions received.

I presented some of the results during the Percona conference in Santa Clara last April 2016. The following is the transposition that presentation, with more details.

Not interested in the preliminary descriptions? Go to the results section

Why new tests?

This Log Buffer Edition goes through various blogs, and selects some of the top posts from Oracle, SQL Server and MySQL.

Oracle:

MOS Note:136697.1 – New HCHECK.SQL for Oracle Database 12c

ORAchk / EXAchk questions.

Cloud control won’t start!

ASMLib is an optional utility that can be used on Linux systems to manage Oracle ASM devices.

ORA-56841: Master Diskmon cannot connect to a …

Could this be Oracle’s influence? has this improved with recent versions?

Percona is glad to announce the release of Percona Server 5.6.30-76.3 on May 25, 2016. Download the latest version from the Percona web site or the Percona Software Repositories.

Based on MySQL 5.6.30, including all the bug fixes in it, Percona Server 5.6.30-76.3 is the current GA release in the Percona Server 5.6 series. Percona Server is open-source and free …

Thanks to everyone who joined us yesterday for our ClusterControl 1.3 release webinar!

Johan Andersson, CTO at Severalnines and creator of ClusterControl, walked us through the latest features of the 1.3 release and demonstrated them live as well. In addition to an overview of ClusterControl’s deployment, monitoring, management and scaling functionalities for MySQL, MariaDB, Percona Server, MongoDB and PostgreSQL, Johan focussed our attention on new features around key management, operational reports and more.

One feature-set that triggered particular interest in yesterday’s audience was the automated deployment of a production setup of NDB / MySQL Cluster: users can create a production setup of NDB/MySQL Cluster from ClusterControl and deploy management, SQL/API and data nodes - all via the ClusterControl interface.

The replay of this webinar and the slides are now available for viewing online:

…