Marmota Technica

JMX metrics in Reconnoiter

2011-11-05T22:35:00.000+01:00

We started using Hadoop, written in Java and it exposes it's metrics thru JMX, which is a Java standard for monitoring and metrics publishing. Since we use Reconnoiter for all other metrics collection and graphing, I wanted to get this JMX data into it. Reconnoiter has a Java component, called Jezebel, that functions as a bridge between Java world and Reconnoiter. What it does is it listens on

DRCP Monitoring with Reconnoiter

2011-03-19T10:51:00.000+01:00

This is a second part of my previous article Collecting Oracle metrics with Reconnoiter. If you are using Database Resident Connection Pooling (DRCP) for connecting your application to Oracle Database (and if you are serious about scalability you should), then you probably know about the (G)V$CPOOL_STATS view, which shows the usage statistics of the pool, such as number of succesful connections

Collecting Oracle metrics with Reconnoiter

2011-03-09T21:34:00.003+01:00

Oracle database makes your life, as an operator, easier by measuring and providing tons of metrics. These metrics range from wait time counters, thru I/O operations and sizes to number of failed logins. Each new version adds even more useful metrics. For example, Oracle 11gR2 collects 628 different metrics. These metrics are generally available thru the (G)V$SYSSTAT system view. This view can be

Hidden errors in PHP affect performance

2010-03-02T20:03:00.013+01:00

I've come across an interesting thing recently, that I didn't think mattered, but, as I'm about to demonstrate, it does. So we all know about different levels of error reporting in PHP, right? We all know, that we must pay close attention to E_WARNING and above, and sometimes the occasional E_NOTICE carries some wisdom. (Almost) nobody cares about those annoying E_STRICT messages. In fact, even

Index usage monitoring in Oracle

2009-07-30T22:47:00.003+02:00

Indices (or indexes, if you will) are always good, right? Well, Tom Kyte would disagree with you and so would I. In fact, indices will always impede data manipulation performance, so they should be used only where they are useful in queries. But determining if an index is useful can be sometimes pretty difficult, mainly in a complex application with thousands of different queries, some even

The hunt for the UNKNOWN SQL in Oracle

2009-07-15T21:21:00.005+02:00

If you are looking at your AWR report or browsing thru performance views in your Oracle Enterprise Manager console, chances are, that some of those SQLs, eating at your CPU or I/O bandwidth are marked as UNKNOWN. This is frustrating, to say the least, but in cases when these mysterious queries are killing your database, it may become a matter of life and death to find out just what does the

Performance analysis reports in Oracle

2009-07-10T11:46:00.004+02:00

Sometimes you wonder why your database is slow or you just want to know what those oompa-loompas inside the Oracle black box are up to. One of the tools in your investigation can be the so-called Automatic Workload Repository, which contains an overload of information about what is going on in your database.Some information from AWR can be seen inside the Enterprise manager console, but for

How to build Oracle Instant client under Linux

2009-06-02T16:45:00.004+02:00

The Oracle Intant Client is a minimalistic version of necessary runtime libraries needed to run an application which uses an OCI interface to connect to the Oracle database. In this article I will describe how to build your very own Instant client.If you ever installed a full Oracle client, you know how painfull process it is and how much diskspace you need. Especially if you are running a large

Calling SAP RFC from PHP thru message server

2009-05-28T15:38:00.005+02:00

If you have the need to call your SAP R/3 system from PHP (which we do), you have several possibilities to do so. One of them is using the proprietary RFC protocol. Fortunately, there exists a PHP SAPRFC library for this purpose. Because we want high availability and scalability in our SAP, we use multiple application servers and spread the load between them with help from a so called message

Building a load balancer with open source software

2009-05-25T23:33:00.011+02:00

So your website has reached a level of traffic, where your old server is getting slower and slower and your users just keep coming and coming. You can always throw more hardware at it, but it gets more and more costly, when you want high performance from a single machine.And then there is the other problem: when your web server dies, your website dies with it. Of course you keep backups of