Re: version upgrade

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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