Author - Stephane Combaudon

Estimating potential for MySQL 5.7 parallel replication

Unlike MySQL 5.6, where parallel replication can only be used when replicas have several schemas, MySQL 5.7 replicas can read binlog group commit information coming from the master to replicate transactions in parallel even when a single schema is used. Now the question is: how many replication threads should you use?
A simple benchmark
Let’s assume […]

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RocksDB 101

After we announced that Percona offers support for RocksDB, we saw many people looking for more details about this storage engine. Here is a quick list of some of the most frequent questions we get.

Q: What is RocksDB?
A: Quoting the homepage of the project:
RocksDB is an embeddable persistent key-value store for fast storage. RocksDB can […]

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MongoDB and Percona TokuMX Security Guidelines

Several reports we’re published in the news about how easy it is to access data stored in some NoSQL systems, including MongoDB. This is not surprising because security was rather relaxed in earlier versions of MongoDB . This post lists some of the common vulnerabilities in MongoDB and Percona TokuMX.
Network Security
One key point is […]

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super_read_only and GTID replication

Percona Server 5.6.21+ and MySQL 5.7.8+ offer the super_read_only option that was first implemented in WebscaleSQL. Unlike read_only, this option prevents all users from running writes (even those with the SUPER privilege). Sure enough, this is a great feature, but what’s the relation with GTID? Read on!
TL;DR
Enabling super_read_only on all slaves when using GTID […]

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How much could you benefit from MySQL 5.6 parallel replication?

I have heard this question quite often: “At busy times, our replicas start lagging quite frequently. We are using N schemas, so which performance boost could we expect from MySQL 5.6 parallel replication?” Here is a quick way to give you a rough estimate of the potential benefit.
General idea
In MySQL 5.6, parallelism is added […]

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The MySQL query cache: Worst enemy or best friend?

During the last couple of months I have been involved in an unusually high amount of performance audits for e-commerce applications running with Magento. And although the systems were quite different, they also had one thing in common: the MySQL query cache was very useful. That was counter-intuitive for me as I’ve always expected […]

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SELinux and the MySQL init script

I recently worked with a customer who had a weird issue: when their MySQL server was started (Percona Server 5.5), if they try to run service mysql start a second time, the init script was not able to detect that an instance was already running. As a result, it tried to start a second […]

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Percona XtraDB Cluster (PXC): How many nodes do you need?

A question I often hear when customers want to set up a production PXC cluster is: “How many nodes should we use?”
Three nodes is the most common deployment, but when are more nodes needed? They also ask: “Do we always need to use an even number of nodes?”
This is what we’ll clarify in this […]

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