Jan Wieck wrote:
> 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.
Paranoid means also don't trust in new hw without have test it for a while.
How ever if I leave unchanged all interfaces and all my test cases are
continuously passing ( 3200 different test in my case ) all the night long
I'm quite sure that the schema change will not hurt nothing. However I have to
say that add come column, with default value and a check on it is no to
doable with very bigtables. Fortunately with the 8.0 you can do these tasks
in one shot.
Regards
Gaetano Mendola
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