Introduction For a long time MySQL server supported only one trigger for every action (INSERT, UPDATE, DELETE) and timing (BEFORE or AFTER). In other words, there could be at most one trigger for every pair (action, timing). It means that a user couldn't assign for example two BEFORE INSERT triggers for the same table t1. To workaround this restriction and allow several actions to fire on some table event, a user had to implement several stored procedures (one for each activity that would be implemented as independent trigger), create trigger for a table and call this stored procedures from the trigger. As of MySQL 5.7.2 this limitation has been removed. It means that starting the MySQL 5.7.2 a user can create for example, two BEFORE INSERT triggers, three AFTER INSERT triggers and four BEFORE UPDATE triggers for table t1. And this triggers will be called in the prescribed order determined (in generally) by the sequence in which triggers …

Hello,

I am Shivji Kumar Jha (shiv), a graduate from BIT Mesra who fell in love with MySQL sometime ago. I am one of those lucky ones who got to work at MySQL as well and I thoroughly enjoy the experience every single day. I believe this is the golden age of technology and I aim to  contribute my bit to it affecting millions of people through an open source software – the most popular open source database on web – MySQL ! At MySQL I am currently working as a software developer with the replication team, which provides high-availability solution built into MySQL server. My area of expertise revolves around analyzing and enhancing performance Database replicas, enhancing the replication monitoring tools. This blog is an attempt to reach out to people and share the tiny details I know about MySQL Replication. The views expressed on this blog are my own and do NOT necessarily …

In talking to existing MongoDB users and TokuMX evaluators, I’ve often heard that the performance of MongoDB is very good as long as your working data set fits in RAM. The story continues that if your working data set grows to be larger than the RAM on your server, the built-in sharding capabilities of MongoDB allow you to scale horizontally.

As my benchmarking presentation at Percona Live 2013 pointed out, I’m never one to accept something without at least running it once myself. I decided to run my Sysbench for MongoDB benchmark on an in-memory workload, meaning that all of the data fits …

MySQL Tech Day @Paris

We're happy to announce you that MySQL Tech Day will take place in Paris on Oct 10, 2013 in Oracle main office. It'll be a full day event giving you an occasion to listen directly from Oracle developers about most of the improvements made recently within MySQL 5.6 and 5.7 development.

One of MySQL’s continued values is to be easy to use. A key part of this, is making sure the default configuration is kept up to date and safe for everyone.

Internally, these configuration changes are made in close cooperation between our engineering and support teams, who are in the best position to provide insight into customer impact.

For MySQL 5.6, hats off to James Day who led the project internally. Taken directly from James’ blog, here is the list of changes made:

From my testing MySQL Cluster on the Raspberry Pi’s I thought I’d share this little extract, just in case someone tries the same, some day.. somewhere.. why? I don’t know.

Ok, so when we pull the plug on one of the pi’s, we have of each component falling down, but because one of them is the arbitrator (node-id=2) then cluster falls over.

Before the ‘accident’:

  ndb_mgm -e show

Connected to Management Server at: localhost:1186
Cluster Configuration
———————
[ndbd(NDB)]     2 node(s)
id=3    @10.0.0.6  (mysql-5.5.25 ndb-7.3.0, Nodegroup: 0, Master)
id=4    @10.0.0.7  (mysql-5.5.25 ndb-7.3.0, Nodegroup: 0)

[ndb_mgmd(MGM)] 2 node(s)
id=1    @10.0.0.6  (mysql-5.5.25 ndb-7.3.0)
id=2    @10.0.0.7  (mysql-5.5.25 ndb-7.3.0) …

From my testing MySQL Cluster on the Raspberry Pi's I thought I'd share this little extract, just in case someone tries the same, some day.. somewhere.. why? I don't know.

Ok, so when we pull the plug on one of the pi's, we have of each component falling down, but because one of them is the arbitrator (node-id=2) then cluster falls over.

Before the 'accident':   ndb_mgm -e show

Connected to

Eight MySQL Connect Hands-on Labs will offer you the chance to get hands-on experience about various topics. They will all take place in room Franciscan A/B at the Hilton Union Square and here is the schedule:

MySQL’s EXPLAIN Command New Features - Evgeny Potemkin, Oracle
Saturday, 11.30am - 12.30pm

MySQL Replication Best Practices - Luis Soares, Oracle
Saturday, 1.00pm - 3.30pm

MySQL Cluster Monitoring: Availability and …

Continuing with my wishlist, I’ll add windowing functions. They’re enormously powerful. They allow you to extend relational logic beyond the strict boundaries of tuples. In MySQL at present, one must use ugly hacks to preserve state from one row to the next, such as user variables — which are not guaranteed to work if the optimizer changes the query plan.

And yeah, PostgreSQL and SQL Server have windowing functions too, and once you’ve used them it’s a little hard to go back. This is in fact one of the main things I hear from people who love PostgreSQL for what I consider to be legitimate reasons.

Windowing functions extend the uses of SQL (sometimes awkwardly, sometimes elegantly), into areas you can’t really go without them. Time-series data, for example, or more powerful graph processing. These things must be done externally to SQL otherwise, in ugly procedural logic.

Windowing functions together with CTEs …

Hello :)

I am Narayanan Venkateswaran (mostly referred to as VN :) ) and work at Oracle in the MySQL team.

This is a great place to be and I love every moment of my work on this great product. I have brilliant colleagues and a fantastic work environment.

In this blog I intend to write about development in MySQL and general database topics that are of interest to me.