Cache files date altered

[eluser]aroth[/eluser]
I am using cache-ing for the first time on my CI Application, for some specific queries. All goes well, except that I noticed the timestamp of the cached files is updated on every execution of the queries. The queries are simple SELECTs, strictly identical from execution to execution, and the results are identical.

Is this timestamp change normal? Are the cache files re-written (this would defeat the whole purpose of caching, making things even worse), or just the files timestamp gets updated, maybe because of the locking mechanism?

I am using for development Windows XP and CI 1.7.2
Thanks for any comments

[eluser]aroth[/eluser]
:-S My mistake... missed enabling cache with $this->output->cache(n);