[Info-Ingres] Cache hit ratio 20% ummm is that good?

[Roy Hann]

"Paul White" <shift7solutions at gmail.com> wrote in message 
news:mailman.65.1195102916.18164.info-ingres at kettleriverconsulting.com...
>I was horrified to find a cache hit ratio of under 20% on one of my 
>customer
> servers recently. Upon investigation the story is more interesting...
>
> Fix Calls  169880982
> Hits        28015058

> I run a trace point DM420 every hour to collect useful stats on the cache.
> Somewhere between 10am and 11am the FIX CALLS reset back to zero. Then 
> later
> the next day the HITS reset back to zero. It seems 2^32 is the maximum.

I've not observed that myself.  What version is this?  What does IMA say?

[snip]
> Have I bored you all to tears?

Nope.  I can truthfully say this is one of the three most interesting post 
this week.

> The server is rebooted monthly so the
> problem only shows up after some very heavy processing (eg a process went
> crazy)
>
> ps.. Would anyone like to comment on my GREAD numbers? I think they are 
> too
> high for a transaction based database.

GREADs are a pain.  At some point in the recent past, some over-eager soul 
decided to change that counter to indicate the number of pages read by group 
reading, rather than the number of group read operations.  I never remeber 
which version the change was introduced, and I am not sure I remember 
whether it has been reversed or not, and if so, in which version it was 
reversed.

Roy