We make ‘null’ mistakes

Wherever software is created, mistakes are being made. Software providers often presume their products are bug-free, but software of that kind doesn’t exist. Our departments works hard to prevent it, yet in our HIquality Life Cycle new bugs could still be introduced, even in the oldest modules that have been in use for over 25 years already. 

HIquality bug cycle

Usually our customers are satisfied with our product suite. At customer support I never receive information about the successful implementations. I got to know our software through the problems that occur, and in almost 15 years of acceptance testing and customer support, I’ve seen all kind of bugs passing by.
HIquality bug cycleSoftware crashes and never ending loops are nasty. Worse are those bugs that are not that visible in the beginning, but keep on growing in the course of time.
Recently we caught such a bug in our longest existing product HIquality Identify.

Data quality life cycleHIquality Identify is often used in search applications. Just like police and justice use “descriptions” of a criminal, HIquality Identify uses descriptions of source data to detect the right records in a database. Source records are decomposed to core words and the phonological codes of the core words of streets, names and places are stored in the description table. This table is the base of the search application.

Nulls, nels and nols
Whenever a source record is changed, the descriptions have to be updated as well. A synchronize procedure is used to keep the description table up to date.
Due to a little mistake in this procedure we recently released a version of the Oracle Upgrade pack, that didn’t recognize null values in the database any more. Empty fields in the database resulted in core words with the value ‘null’, and the phonological codes ‘nel’ and ‘nol’.
As a result the scores of evaluations became less accurate, and end scores became too high. The phonological codes of the core words are used as indexes. These indexes are used to pre-calculate the maximum number of evaluations. Since more and more of these fields are changed to nul nel and nol, after several months, instead of search results time-outs occur, stating that not enough relevant search data was entered. 

Did you want to know this?
In a short time we figured out which customers received this special software release, and our consultants visited them for an upgrade. In the end all of them upgraded without knowing the actual reason or what kind of harm potentially could have been caused.
As a customer you want problems to be repaired and bugs to be fixed, without knowing every single detail. Is this nol-worm kind of virus something you would have wanted to know about? Probably not. In case you will have nightmares about nulls, nels and nols in your database, you can contact me any time at Human Inference’s Customer Support, where I cope with all those kind of things that can go wrong in software.

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