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Application auditing - an example why I don't work at the weekend...

Ever had a situation where you're OLTP requirements are impeded by your OLAP implementation, well to put it another way - have you ever come across an auditing solution that causes transactions to timeout when you're trying to save data into your production database.

Well the answer for me is far to often for my liking and this is an example of 'synchronous auditing' and I believe this is an anti-pattern in the making. I'm firmly in the camp that believes auditing should be done asynchronously by a different (application) process. The reasons why I think it's an anti-pattern is because, if how you audit affects the performance of your production database then your performance is going to degrade overtime, and if you insert 500,000 audit records a day that's going to occur relatively quickly. Now DBAs would say lets put a maintenance plan in place to clear down\manage the audit database, or even remove the synchronous auditing and perform a batch load once a week out of normal days operation - AT THE WEEKEND OR AFTER HOURS...

I'm not going to support a such a process or help out when such a process fails to bring the production system back online because the batch load failed - MY WEEKENDS ARE FOR ME...

I design auditing systems that allow production-time maintenance of OLAP databases with no affect to OLTP databases and this is achieved by asynchronous auditing via transactional message queues.

You design your application such that when you need to create an audit record for a user\system action you write this to a message queue transactionally as part of the behaviour (business requirement). There is then another independent process monitoring & processing the audit records (in the message queue) into the OLAP database, it's important this process can be controllable so that it can be disabled when ever the OLAP database requires maintenance, i.e. DURING WORK HOURS NOT AT THE WEEKEND. Whilst the process is disabled the audit records will just accumulate on the message queue and as long as disk space is available you won't loose anything - (RAIDing etc).

Auditing user\system actions is always business requirement - we don't track what user\system do for our benefit so why do it as an after thought...

Oh and you can probably guess I hate triggers on tables too ;)



Awkward Coder
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