Buffer Waits

I was poking around and took a look at v$waitstat:

CLASS                   COUNT       TIME
------------------ ---------- ----------
data block              15079       6348
sort block                  0          0
save undo block             0          0
segment header              7          0
save undo header            0          0
free list                   0          0
extent map                  0          0
1st level bmb               2          0
2nd level bmb               1          1
3rd level bmb               0          0
bitmap block                0          0
bitmap index block          0          0
file header block          13          1
unused                      0          0
system undo header          0          0
system undo block           0          0
undo header              8633       1071
undo block               1440          7

Looks like "data block" and "undo header" are a serious problem. It seems that every tablespace was created with ASSM enabled. I've read in some places that ASSM is supposed to fix the data block contention, while others say it does nothing and the real way to fix this is using FREELISTS. This is a highly OLTP system. I know there are thousands of things that can be looked at, but, which is correct here? ASSM or non-ASSM? That may make a significant difference?

We're on 10gR2.

I'm still reading other sites and such, but was looking for everyones thoughts and opinions. Received on Thu Nov 12 2009 - 11:21:36 CST