Should I delete all the files in cache_dirs after deleting 'log' file in the first cache_dir ?

Hi,
Several days ago, the hard disk had a problem and we fixed it physically.
So squid had to start from the beginning.
After this happened, the cpuusage goes high and memory usage is also high than
I expect to do. And disk usage go high unlike what it used to be
(about 15 % higher) but the hitratio does not go better.
Why does the squid work like this ?
Now, I doubt that when log file in the first cache_dir was destroyed and
squid did work again, I should have deleted all the files in the cache_dirs.

Now It seems that 'log' file has the indices for the contents after
restarting squid and in the cache_dirs there are so many contents which
never will be fetched anymore.
I think these make the performance of squid lower.
My guess is right ?
Please let me know.

-Hyojung Hwang

-- 
    *    _  _	  
    ||_|| ||_| 	  Hwang, Hyojung / jung@jean.kotel.co.kr / 82-2-526-5235
  |_|       _|_	  Internet Team  / Multimedia Laboratory / KT R&D Group
           |_|	  137-792, 17 Umyun-Dong, Seocho-Gu, Seoul, Korea