I ran into a weird little error while trying to tune the performance of a query in the oracle database. A table had an index on a VARCHAR2 column. After a fair number of inserts were made the population of this table grew to 1.5 million records. A query that did an join on the VARCHAR2 column was talking ages to get the results. Well, it was taking 900ms actually but the SLA for the API call is way below that.
An “explain plan for QUERY” statement was run followed by a select from plan_details. It turns out the index is never used and a full table scan was used to get the data. Hence the problem.
Sun has a wide range of certifications to offer. Ever since java EE6 was released, changes have been made to the certification hierarchy and content to reflect the new specifications. Sun is also offering a discount of 10% to those that register for training / certification updates by Jan 31st 2010. Here is a comparison of the certification hierarchies
Old hierarchy:
New hierarchy:
The new hierarchy provides paths that are more specialized than the ones before. For example you can be a JSF expert. Web service + security is another specialization. Combining these certifications together can also earn you the title of a “Master“.
A few days ago the EU had approved the takeover of Sun microsystems by Oracle. This brings to an end the long awaited acquisition. There have been several blog entries about the fate of the open source projects that Sun currently supports. I have read some of the arguments put forward about why developers should move away from / use certain projects.
However I also find myself in a dilemma. I installed GlassFish and deployed a few apps on it recently. I found it interesting and was impressed with it within a few minutes of using it. MySql is also a great open source project. There are many tools built around the database and it competes well with PostGresql. Netbeans is also a great IDE and supports glassfish.
I have been a tad busy fixing some weird little bugs lately. They helped me appreciate the multitude of things that can go wrong in a live environment and served as a gentle reminder that you should always be on your heels.
Here they are
1. LDAP and the user
A web application product was configured to use an LDAP directory structure. The directory was segregated into roles / groups / OUs, the usual. One of the users had trouble logging into the product. This was weird because this person was a valid user and Outlook seemed to recognize him. Outlook uses the same LDAP tree. So I dug into it. The easiest way to check what is going on is to use a LDAP directory browser. I use the one provided by Novell for free. The LDAPs support is not great but it will do for basic lookups.
There are times when you work with SSL traffic. Your website might be protected with a certificate so that traffic between you and the client is secure. At times like this, being a developer is troublesome. Browser cache settings need to be analyzed by looking at the HTTP headers. Encoding / Content type may need to be analyzed to ensure that a particular page is displayed correctly. These things cannot be looked into if the traffic is secure. There are situations under which the environment is secure but you must still sniff the data. So how do you manage this ?
Tools like Charles (A debugging proxy) help you do this. Charles allows you to proxy to a secure connection over a protocol like HTTPS and still read the traffic. So how does it do this ? Lets have a look.