redo copy "sleep rate" is this a problem?

I ran one of the reports from Oracle Internals and see one thing that jumps out at me, the redo copy has a "sleep rate" of nearly 90%. What does this mean?

Do we need more rollback segments? bigger segments? Is there a particular type of query that would be a problem? Is this even a problem?

LATCH TYPE IMPACT SLEEP RATE WAITS_HOLDING_LATCH LEVEL#
------------------------------ ----------- ---------- ------------------- ----------
redo copy 21551 89.58% 0 5

The entire report is below, in case anyone spots anything strange:

LATCH TYPE IMPACT SLEEP RATE WAITS_HOLDING_LATCH LEVEL#
------------------------------ ----------- ---------- ------------------- ----------

cache buffers chains		    193859	0.00%		    47829	   1
library cache			    192286	0.14%		   333955	   5
cache buffers lru chain 	    167315	4.93%		   151758	   3
virtual circuit queues		     99488	0.03%		    98592	   8
shared pool			     48845	0.04%		   313381	   7
virtual circuits		     39824	0.04%		   125260	   8
redo writing			     34698	0.07%		   114821	   5
enqueue hash chains		     30060	0.05%		      135	   4
Checkpoint queue latch		     24730	0.01%		   162065	   7
redo allocation 		     21567	0.03%		    56580	   6
redo copy			     21551     89.58%			0	   5

LATCH TYPE			    IMPACT SLEEP RATE WAITS_HOLDING_LATCH     LEVEL#


------------------------------ ----------- ---------- ------------------- ----------


transaction allocation		     19077	0.04%		    23514	   8
session idle bit		     17965	0.01%			0	   1
undo global data		     14390	0.03%		    12053	   5
session allocation		     12642	0.05%		    35032	   5
enqueues			     11625	0.02%		    12704	   5
virtual circuit buffers 	     10602	0.00%		     8976	   0
dml lock allocation		      5747	0.02%			0	   3
messages			      3112	0.01%		    79128	   8
list of block allocation	      2993	0.01%			0	   3
sequence cache			      2745	0.02%		     4531	   8
multiblock read objects 	       492	0.01%		     2190	   3

LATCH TYPE			    IMPACT SLEEP RATE WAITS_HOLDING_LATCH     LEVEL#


------------------------------ ----------- ---------- ------------------- ----------


latch wait list 		       225	0.09%			0	   9
modify parameter values 	       143	0.06%		      212	   0
cache buffer handles			56	0.00%		      172	   3
row cache objects			18	0.00%		      193	   4
user lock				13	0.01%		       17	   3
Token Manager				 5	0.00%			6	   6
Active checkpoint queue latch		 3	0.00%		       16	   5

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greg Received on Wed Nov 17 1999 - 22:22:49 CST