Thu, 2015-04-02 12:02jean-françoisgagné

(The previous post, Better Parallel Replication for MySQL, is Part 1 of the series.) Parallel replication is a much expected feature of MySQL. It is already available in MariaDB 10.0 and in MySQL 5.7. In this post, a very nice side effect of the MariaDB implementation is presented: Slave Group Commit.

(If you are not familiar with parallel replication and its implementation, read the previous post in this series to better understand this post.)

To allow better parallelization on slaves, MariaDB 10.0 and MySQL 5.7 have parameters that control the commit group sizes on the master. Those parameters are …

I contributed an article on modern database storage engines to the recent DZone Guide To Database and Persistence Management. I’m cross-posting the article below with DZone’s permission.

Readers of this guide already know the database world is undergoing rapid change. From relational-only, to NoSQL and Big Data, the technologies we use for data storage and retrieval today are much different from even five years ago.

Today’s datasets are so large, and the workloads so demanding, that one-size-fits-all databases rarely make much sense. When a small inefficiency is multiplied by a huge dataset, the opportunity to use a specialized database to save money, improve performance, and optimize for developer productivity and happiness can be very large. And today’s solid-state …

I contributed an article on modern database storage engines to the recent DZone Guide To Database and Persistence Management. I’m cross-posting the article below with DZone’s permission.

Readers of this guide already know the database world is undergoing rapid change. From relational-only, to NoSQL and Big Data, the technologies we use for data storage and retrieval today are much different from even five years ago.

Today’s datasets are so large, and the workloads so demanding, that one-size-fits-all databases rarely make much sense. When a small inefficiency is multiplied by a huge dataset, the opportunity to use a specialized database to save money, improve performance, and optimize for developer productivity and happiness can be very large. And today’s solid-state …

A friends table is the cornerstone of social applications. Its purpose is to define relationships and help answer the question what are my friends doing.

Here is an example friend’s table:

 CREATE TABLE `friends` (
  `user_id` bigint(20) unsigned NOT NULL,
  `friend_id` bigint(20) unsigned NOT NULL,
  `auto_ts` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (`user_id`,`friend_id`),
  KEY `user_id-auto_ts` (`user_id`,`auto_ts`),
  KEY `friend_id-auto_ts` (`friend_id`,`auto_ts`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci


With the table above we can get a list of user_ids a user follows (following), or a list of people who follow said user (followers), or get a list of mutual follows. This is a very simple table structure yet very powerful.
…

We are excited to announce that VividCortex now supports Redis, a popular open source database. After announcing PostgreSQL support in January, our brainiacs continue to create a unified solution for diverse systems.

Baron Schwartz explains the product development further. “Redis is an important database for VividCortex, both strategically and commercially, due to its incredible popularity and our own usage. We rely on Redis to help analyze the massive amounts of time-series data we receive from agents running on customer systems. Although it is a high-performance and reliable system that generally just works, that doesn’t mean it can’t be improved. We were able to significantly optimize our usage of Redis with the network-traffic visibility built into our agents. Most of our …

Most of the time I like pt-kill, but sometimes it gets a little overzealous and kills a query that I need. That's why I'm glad Percona created pt-reanimate so I can bring those important queries back to life. Of course the queries are not exactly the same when they come back, but at least they come back.

Here's an example of pt-reanimate in action. First I add a column to a large table:

alter table big_table add column new_col int;

Here is my DDL in the processlist table:

+---------+------+----------------+----------------------------------------------+ | command | time | state | info | +---------+------+----------------+----------------------------------------------+ | Query | 146 | altering table | alter table big_table add column new_col int | …

I have done a lot of benchmarks of MySQL Cluster on large servers which
is obviously very interesting. As mentioned in a previous blog I have
an Intel NUC machine now easily accessible. So I thought it would be
fun to make some benchmarks on this machine to see how fast MySQL Cluster
runs on small HW.

First a little description of the HW. The CPU is an Intel Core i5-4250
CPU. It runs at 1.3GHz and have a turbo frequency of 2.3 GHz. The CPU
has two cores and each core can run two threads simultaneously
(called hyperhtreading in Intel CPUs). It comes with the box containing
the motherboard and the CPU. Then you buy one or two DRAMs to it and an
SSD drive. I installed two DDR3L DRAMs which gives me a total of 16GByte
memory in the machine. In addition I installed an SSD drive of 256GByte.
The box fits nicely into the palm of your hand.

On …

A Quick Security Update

Starting with MySQL 5.7.6, the following functions are now deprecated:

• DES_ENCRYPT
• DES_DECRYPT
• ENCRYPT

DES (Data Encryption Standard) is known to be less secure and slower than other available encryption methods. There are also many …

Yes, after many hours, late nights, hair pulling, some private yelling:

core@master ~/mysql_replication_kubernetes/galera_sync_replication $ kubectl get pods
POD                 IP                  CONTAINER(S)        IMAGE(S)                                     HOST                            LABELS              STATUS
pxc-node1           10.244.72.7         pxc-node1           capttofu/percona_xtradb_cluster_5_6:latest   172.16.230.136/172.16.230.136   <none>              Running
pxc-node2           10.244.15.2         pxc-node2           capttofu/percona_xtradb_cluster_5_6:latest   172.16.230.134/172.16.230.134   <none>              Running
pxc-node3           10.244.42.2         pxc-node3           capttofu/percona_xtradb_cluster_5_6:latest   172.16.230.135/172.16.230.135   <none>              Running

mysql> show status like 'wsrep_incoming_addresses';
+--------------------------+----------------------------------------------------+
| …

Wed, 2015-04-01 10:28guillaumelefranc

Upgrading a running MariaDB Galera Cluster from 5.5 (previous stable) to 10.0 (stable) is a question which comes up frequently with Remote DBA customers. Although a standard migration from 5.5 to 10.0 is well covered in the Knowledge Base, Galera Cluster upgrades haven’t been really documented in detail now. This howto will cover upgrades on CentOS or RHEL 6 but a similar logic can be applied to Ubuntu/Debian as well.

Prerequisites

It is indeed possible to do a rolling cluster upgrade if the Galera API and provider versions are compatible. Please refer yourself to my previous blog article (https://mariadb.com/blog/deciphering-galera-version-numbers) if you need to understand more about Galera versioning. A simple way to ensure Galera compatibility is to upgrade first to the latest 5.5 Galera …