The Write Ahead Log (WAL) is one of the most important components of a database. All the changes to data files are logged in the WAL (called the redo log in InnoDB). This allows to postpone the moment when the modified pages are flushed to disk, still protecting from data losses.…

Cluster connection pooling
The new MySQL Cluster 7.6 GA supports NDB connection pooling – using multiple NDBAPI connections from a single mysqld to NDB – to allow increased concurrency and throughput.

Cluster connection pooling has been supported in MySQL Cluster for quite a while.

…

Let them stay together. In the last YEARS, I have seen quite often that users, when installing a product such as PXC, instead of spending five minutes to understand what to do just run iptables -F and save. In short, they remove any rules for their firewall.

With this post, I want to show you how easy it can be to do the right thing instead of putting your server at risk. I'll show you how a slightly more complex setup like PXC (compared to MySQL), can be easily achieved without risky shortcuts. iptables is the utility used to manage the chains of rules used by the Linux kernel firewall, which is your basic security tool. Linux comes with a wonderful firewall built into the kernel.

As an administrator, you can configure this firewall with interfaces like ipchains — which we are not going to cover — and iptables, which we shall talk about. iptables is stateful, which means that the firewall can …

This time we will look at the differences in updating records between MongoDB and the MySQL Document Store.  Syntactically they are pretty different.  I am still following the Getting Started With MongoDB article for example queries.

Updating Records
In Mongo we update thusly:
> db.restaurants.update(
... { "name" : "Juni" },
... {
...  $set: { "cuisine" : "American (new)" },
...  $currentDate: { "lastModified" : true }
... }
... )
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
>

The same update in the MySQL Document Store can be a lot different.  We could update using SQL or NoSQL.  I would like to update the document with the change to the cuisine and …

MySQL 5.7.8 introduced much improved version of mysqldump, It’s called “mysqlpump”, mysqlpump is much faster than mysqldump with parallel threads capabilities, There are many other compelling reasons for choosing mysqlpump over mysqldump, This blog is about how mysqlpump can be used for good. mysqlpump is relatively a new utility of MySQL and we are confident that Oracle MySQL will invest more to make mysqlpump efficient, we haven’t recommended mysqlpump in production for any of our customers till date, considering several concerns. The following below are mysqlpump features we are really excited about:

• Supports parallel MySQL logical backup, The resource usage efficiency and high performance backups (we love it !)
• Much better orchestration possible – You can backup selected databases, tables, stored programs and user accounts etc.
• By default mysqlpump will not backup performance_schema, sys schema, …

Last time I was stumped by the MongoDB $gt: operator.  I wanted to look for restaurants in a certain Manhattan burough OR in a zipcode greater than a certain zipcode.  Well, I was getting different results between Mongo and MySQL.

To > or Not To >, That Is the Query
Lets say we have three records with the same key but the values are 1, 2, and "3". Yup, you got it two numerics and one string.  I would expect schema less data to be free flowing, not typed, and pretty much a free for all.  Whoops. Bad assumption on my part for Mongo use.

I added three JSON documents into Mongo as can be seen below:

Join Percona Chief Evangelist Colin Charles as he covers happenings, gives pointers and provides musings on the open source database community.

Much of last week, there was a lot of talk around this article: New research shows 75% of ‘open’ Redis servers infected. It turns out, it helps that one should always read beyond the headlines because they tend to be more sensationalist than you would expect. From the author of Redis, I highly recommend reading Clarifications on the Incapsula Redis security report, because it turns out that in this case, it is beyond the headline. The content is also suspect. Antirez had to write this to help the press (we totally need to help keep reportage accurate).

Not to depart from the Redis world just yet, but …

Occasionally we have customers with MyISAM storage engine approaching us to migrate their database to InnoDB, MyISAM is great if you are just an application like web content management system with no multi-user concurrency challenges but what if you are building an highly transactional data web property ? InnoDB is much preferred for such situations, InnoDB provides Row-level locking (Oracle like) for consistent reads on an multi-user concurrent user high performance database application. InnoDB also guarantees maximum data integrity by supporting FOREIGN KEY, We captured below few interesting points to remember while migrating your database from MyISAM to InnoDB :

• Data of InnoDB tables is stored in *.ibd files, deleting those files will permanently corrupt your database
• InnoDB tables consumes more storage space than MyISAM tables .
• Unlike MyISAM, InnoDB is a transactional database engine. In any typical MyISAM …

In one of the projects I have been working on, one requirement was the ability to stop traffic from reaching a MySQL host which has been lagging behind its master for longer than a specific amount of time and then bring it back online once the lag has gone away. Of course, this is all automated and no human intervention is required.

In this scenario, we are using HAProxy as the load balancer, and I will walk you through how to configure an agent so we can use HAProxy httpchk to flag the host as up or down, via systemd socket and then automatically set the host as being down/up when applicable, in HAProxy.

I will be setting up a systemd service (I’m running centos7 hosts) and creating a listening socket in the MySQL host we want to monitor so haproxy can have access to replication status.

Scenario:

master: po-mysql1
slaves: po-mysql2, po-mysql3, po-mysql4
secondary slaves: …

Generally, when I'm analyzing MySQL Performance on Linux with "localhost" test workloads, I'm configuring client connections to use IP port (loopback) to connect to MySQL Server (and not UNIX socket) -- this is still at least involving IP stack in the game, and if something is going odd on IP, we can be aware ahead about. And indeed, it already helped several times to discover such kind of problems even without network links between client/server (like this one, etc.). However, in the past we also observed a pretty significant difference in QPS results when IP port was used comparing to UNIX socket (communications via UNIX socket were going near 15% faster).. Over a time with newer OL kernel releases this gap became smaller and smaller. But in all such …