Niggling,
sporadic errors the web log rarely shows
Additional Information
User Journey monitoring
User Journey Load Testing
Further real world examples with SciVisum
case studies
Article
Do your website visitors ever experience niggling, sporadic errors such
as stalling, time-outs or backward steps when trying to purchase something?
Are they ever given old pages with long-discontinued offers? Apart from
complaints to the call centres, how would you ever know? Such sporadic
problems might never show up in the web log.
User Journey (UJ) monitoring doesn't only address the big problems in
life. It can also be very useful in detecting intermittent problems, apparently
small in themselves, but capable of frustrating site users, reducing sales
and making disappointed visitors less likely to return. We've found that
on most sites at any point in time such errors can affect an appreciable
percentage of visitors.
In some UJ tests sporadic errors have been as high as 5%.
Such sporadic problems rarely occur on a regular basis nor for significant
lengths of time. They are often invisible to existing monitoring systems
as most monitoring software looks at page headers to see if the page delivery
is OK and can give you a positive response even though there are errors
in page content.
By its thorough and repetitive nature, UJ monitoring helps reveal irregular
problems. Moreover, it verifies page content rather than simply checking
page headers.
Inexpensive Remedies
Sporadic issues are often much less expensive to remedy than you might
at first think. They often occur as a result of website developers inadvertently
designing in performance limits. There are a number of places in web design
technology where such limits arise. At SciVisum we often see problems
resulting from incorrect configuration especially at points where web
systems interface with other technology blocks. How often do you find
a system that is struggling to cope with demand even though it has had
bigger hardware thrown at it - and yet it continues to perform badly?
During real world testing we spot many sporadic problems that can be easily
and inexpensively solved. They rarely show up in the logs. Here are just
a few from recent monitoring programmes.
Backward steps
No errors appeared in the web logs, yet a pure-play retailer discovered
that a small percentage of would-be purchasers were being thrown back
several steps in the purchasing process.
Old news
The website of a leading high street retailer presented out-of-date special
offers to a number of users. It's something that can occur when not all
servers in your farm are delivering the same content. Particularly important
for landing pages, affiliate or CPC input pages, such sporadic errors
can prove embarrassing to resolve and often result in loss of revenue.
Personal details
The site of a major financial provider under heavy load conditions revealed
the name and/or credit card details of other users at the end of the purchase
process - for a small percentage of users. Again, no presence of errors
had shown up in the logs.
Stalling
Here the website experienced a slowdown when credit card transaction were
sent to a third party payment provider. It was due to the credit card
processor placing, by mistake, a wrong threshold on the number of concurrent
payments that they could handle and by the configuration of the payment
system, which was limiting the rate at which credit card transactions
could be handled.
Time-outs
The call centre of a leading travel company was receiving too many complaints
about their slow online service. UJ monitoring identified 'race conditions'
- certain searches by clients took up huge amounts of server power, leaving
other users with a very slow experience. The client's web hoster had wanted
to provide greater capacity hardware at a substantial cost - quite unnecessary
once the actual problem had been identified.
User Journey load testing
User Journey load testing can help replicate sporadic problems and pinpoint
the causes. It's not unusual to find high error rates even though the
web farm by all 'normal' measures (CPU load, database queries/second,
memory swap) is a long way from reaching its limits. Sporadic errors often
arise from race conditions in software. User Journey load testing can
often identify a range of coding errors, configuration oversights or database
locking problems that are extremely difficult to find using other methods.
For troubleshooting one-off web performance issues, bespoke consultancy
services adopting a UJ approach - such as SV-function - can be used to
apply a customised suite of tests designed to diagnose sporadic errors
by probing different blocks of the web system.
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