Re: DELETE vs TRUNCATE explanation

On 07/11/2012 04:47 PM, Shaun Thomas wrote:
> On 07/11/2012 03:18 PM, Craig James wrote:
>
>> It strikes me as a contrived case rather than a use case.  What sort of
>> app repeatedly fills and truncates a small table thousands of times ...
>> other than a test app to see whether you can do it or not?
>
> Test systems. Any company with even a medium-size QA environment will
> have continuous integration systems that run unit tests on a trash
> database hundreds or thousands of times through the day. Aside from
> dropping/creating the database via template, which would be *really*
> slow, truncate is the easiest/fastest way to reset between tests.


Why is recreating the test db from a (populated) template going to be
slower than truncating all the tables and repopulating from an external
source? I had a client who achieved a major improvement in speed and
reduction in load by moving to this method of test db setup.

cheers

andrew