Oracle FAQ | Your Portal to the Oracle Knowledge Grid |
Home -> Community -> Usenet -> c.d.o.server -> script for buffer hit ratio ??
I’m seeking some help understanding a PL*SQL script for determining
buffer hit ratios. I picked up the script from Oracle Magazine’s “Tip
and Code Archive.” Specifically, it is “listing 6” located at
http://www.oracle.com/oramag/code/cod46dba.html. As published there,
the section of code dealing with buffer hit ratio has two blocks of
code, one of which is commented out. When I run the code as published,
the buffer hit ratio is reported as a negative number in the
thousands. This made no sense to me, so I uncommented the other block
of code and ran it, getting number that made sense. After closely
analyzing the two methods, I find that the one that was originally
commented out is essentially saying
buffer hit ratio = 1 – physical_reads / (db_block_gets + consistent_gets)
While the originally active code is saying
buffer hit ratio = ((opens_of_replaced_files + db_block_gets) – consistent_gets) / (opens_of_replaced_files + db_block_gets))
Does anyone have any comments on the use or meaning of either of these pieces of code?
TIA
Sent via Deja.com http://www.deja.com/
Before you buy.
Received on Fri Oct 22 1999 - 10:49:37 CDT