Re: Fragmentation X Buffer Cache

From: Connor McDonald <connor_mcdonald_at_yahoo.com>
Date: Tue, 20 Jul 1999 21:36:32 +0800
Message-ID: <37947B5F.38D3@yahoo.com>

Alexandre Wagner Agostini wrote:
>
> Hi folks!
>
> I'd like to know what's the relation (if any) between the fragmentation
> of the database and buffer cache hit ratio. I'm asking 'cause in the
> database I'm administering the hit ratio only got raised after the
> defragmentation. None of the other measures taken, like indexing and
> buffer cache resizing seemed to work.
>
> Thanks already!
> Wagner

If you used exp/imp then the rows will be reloaded back into the database "packed" ie free space within blocks will be all nicely used up (barring pctfree of course)...

Thus you get "more value" for your blocks - that is, each one will probably contain more rows, thus increasing the likelihood of a cache hit, thus increasing your hit ratio...
--

---

Connor McDonald
"These views mine, no-one elses etc etc" connor_mcdonald_at_yahoo.com

"Some days you're the pigeon, and some days you're the statue." Received on Tue Jul 20 1999 - 08:36:32 CDT