On 9/1/2004 9:02 PM, Gaetano Mendola wrote:
Jan Wieck wrote:
Which is another point I was about to ask. How do these people, running those huge and horribly important databases, ever test a single application change? Or any schema changes for that matter. Do they really type "psql -c 'alter table ...' proddb" and believe they are professional users because they know what they are doing?
I do alter table, but of course before to do it, I run my regression test on a database with almost no data inside. Each stored procedure is tested in order to execute each execution path. In 3 years working in this way I had no a singol failure after an alter schema operation.
If it is possible to define a representative but smaller dataset for test purposes, that is certainly doable. Some systems are just too complex to do this. SAP for example recommends a 4 stage deployment scenario in case you do your own application development in R/3 systems. You would have one or more development systems, that deliver their changes into test systems with small and not necessarily representative data. If all tests there succeed, the software is transported into the integration test system, which is basically a copy of the production system with full data. Only if that transport and the following tests succeed, you transport exactly the same set of programs and catalog changes into the production system. Otherwise you reset the integration test system back to be a copy of the production system.
There are a lot of possible levels between playing russian roulette with your data and being paranoid. If a corrupted database can cause the company to go under, some prefer paranoid.
Jan
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