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Percona Server 5.5.53-38.4 is now available

Percona announces the release of Percona Server 5.5.53-38.4 on November 18, 2016. Based on MySQL 5.5.53, including all the bug fixes in it, Percona Server 5.5.53-38.4 is now the current stable release in the 5.5 series.

Percona Server is open-source and free. You can find release details in the 5.5.53-38.4 milestone on Launchpad. Downloads are available here and from the Percona Software Repositories.

Removed Features:

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Introducing the “Safe-To-Bootstrap” feature in Galera Cluster

Galera Clusters are generally meant to run non-stop, so shutting down the entire cluster is not required during normal operation. Yet, if there is a need to perform such a procedure, it is likely that it will be happening under pressure, so it is important for it to complete safely and as quickly as possible in order to avoid extended downtime and potential data loss.

Galera 3.19 includes two important improvements to whole-cluster restart: the “Safe-to-Bootstrap” protection and Gcache recovery. In this article, we will describe the first feature.

Whole-Cluster Restart

First, a few words on cluster restarts in general. Regardless of whether it was an orderly shutdown or a sudden crash of all nodes, restarting the entire cluster is governed by the following principles:

  • Since the old cluster no longer logically exists, a new logical cluster is being created
  • The first node that is being started …
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GNU Parallel and Block Size(s)

I’ve been a fan of GNU Parallel for a while but until recently have only used it occasionally. That’s a shame, because it’s often the simplest solution for quickly solving embarrassingly parallel problems.

My recent usage of it has centered around database export/import operations where I have a file that contains a list of primary keys and need to fetch the matching rows from some number of tables and do something with the data. The database servers are sufficiently powerful that I can run N copies of my script to get the job done far faster (where N is value like 10 or 20).

A typical usage might look like this:

cat ids.txt | parallel -j24 --max-lines=1000 --pipe "bin/  --db live >> {#}.out

However, I recently found myself scratching my head because parallel was only running 3 jobs rather than the 24 I had specified. …

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Strict sql mode and errors

After MySQL version upgrade, there is a possibility that application will start getting error/exception for INSERT/UPDATE operation due missing default data/values as follows,

ERROR:  Field ‘column_name’ doesn’t have a default value

Also above error will trigger for the wrong data type or out of range value for the column with INSERT/UPDATE sql operation.

Reason for this error is new SQL_MODE default values (MySQL 5.7 ) that included STRICT_TRANS_TABLES value in it and sql_mode value in default my.cnf created after installation[ Under /etc/my.cnf or /usr/my.cnf ]

sql_mode MySQL version Default
>= 5.6.6
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About cloud lock-in and open source databases

The cloud is no longer a question of if, but of when. Many IT leaders, however, find that one consistent barrier to their adoption of the cloud is vendor lock-in. What do you do when you are forced to stay with a provider that no longer meets your needs?

But is cloud lock-in a problem?

While it appears that you are able to move your workload from one cloud to another without being penalised economically, (the utility billing methods of the major pay-as-you-go platforms like Amazon Web Services or Azure ensure that you would only pay for services used, rather than paying for provisioned resources that may or may not be used.), the reality is that it might not work if the exact services and resources that you are using aren’t available on the cloud you’re migrating to.

Hardware is commodity, and if Cloud Infrastructure as a Service (IaaS) is just about renting VMs by the hour, then Cloud IaaS …

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All You Need to Know About GCache (Galera-Cache)

This blog discusses some important aspects of GCache.

Why do we need GCache?

Percona XtraDB Cluster is a multi-master topology, where a transaction executed on one node is replicated on another node(s) of the cluster. This transaction is then copied over from the group channel to Galera-Cache followed by apply action.

The cache can be discarded immediately once the transaction is applied, but retaining it can help promote a node as a DONOR node serving write-sets for a newly booted node.

So in short, GCache acts as a temporary storage for replicated transactions.

How is GCache managed?

Naturally, the first choice to cache these write-sets is to use memory allocated pool, which is governed by gcache.mem_store. However, this is deprecated and buggy and shouldn’t be used.

Next …

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Open-Sourcing Yelp's Data Pipeline

For the past few months we’ve been spreading the word about our shiny new Data Pipeline: a Python-based tool that streams and transforms real-time data to services that need it. We wrote a series of blog posts covering how we replicate messages from our MySQL tables, how we track schemas and compute schema migrations, and finally how we connect our data to different types of data targets like Redshift and Salesforce. With all of this talk about the Data Pipeline, you might think that we here at Yelp are like a kid with a new toy, wanting to keep it...

Meet New Versions of dbForge Tools for MySQL

We are glad to announce the release of the updated versions of:

Is Docker Good for Your Database?

This blog post reviews the appropriateness of Docker and other container solutions for your database environment.

A few weeks back, I wrote a fairly high-level blog post about containers. It covered what you should consider when thinking about using Docker, rkt, LXC, etc. I hope you’ve taken the chance to give it a quick read. It’s a good way to understand some of the disciplines you need to consider before moving to a new technology. However, it sparked a conversation in our Solutions Engineering team. Hopefully, the same one that you’re having in your organization: should customers run their database in containers? …

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Inspecting MySQL micro-stalls with pt-stalk

Very often MySQL is much less stable than we realize. In this video I explain how to detect and dianose these MySQL stalls that last for 5-10 seconds or more.

The reason nobody knows about these issues is that they’re:
a) rare
b) intermittent
c) monitoring software can’t catch them

You can use pt-stalk to detect and diagnose such issues. All of the tools I have mentioned in this video are part of Percona Toolkit (no wonder they all start with PT), you can find the toolkit here:

Percona Toolkit

Here’s the main commands I have discussed in this video:

Starting pt-stalk in foreground

# pt-stalk

Starting pt-stalk in background with email notification:

# pt-stalk …
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