This nothing to do with rollback, as fara as I know.
It is to do with redo log buffer latches (copy not allocate latch), it
could be that you have small redo log buffer.#
Reza
Greg Stark <greg-spare-1_at_mit.edu> wrote in message
news:87hfikmnsk.fsf_at_HSE-Montreal-ppp19485.qc.sympatico.ca...
>
>
> 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
>
>
> --
> greg
Received on Thu Nov 18 1999 - 03:40:52 CST
