Jan Wieck wrote:> On 9/1/2004 9:02 PM, Gaetano Mendola wrote:>>> Jan Wieck wrote:>>>>>>> Which is another point I was
aboutto ask. How do these people,>>> running those huge and horribly important databases, ever test a>>> single
applicationchange? Or any schema changes for that matter. Do>>> they really type "psql -c 'alter table ...' proddb" and
believethey>>> are professional users because they know what they are doing?>>>>>> I do alter table, but of course
beforeto do it, I run my regression test>> on a database with almost no data inside. Each stored procedure is tested>>
inorder to execute each execution path.>> In 3 years working in this way I had no a singol failure after an alter>>
schemaoperation.>>> If it is possible to define a representative but smaller dataset for> test purposes, that is
certainlydoable. Some systems are just too> complex to do this. SAP for example recommends a 4 stage deployment>
scenarioin 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
theresucceed, 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
sameset of programs and catalog> changes into the production system. Otherwise you reset the integration> test system
backto be a copy of the production system.>> There are a lot of possible levels between playing russian roulette with>
yourdata 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
nothurt 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
