i/o slave wai in 10.2.0.5 Solaris

Hi

Recently we upgraded a solaris rac database from 10.2.0.4 to 10.2.0.5, after
that we noticed all scatter reads comes with i/o slave wait as well.

For example

select /*+ full(a) */ count(*)
from
 SVV.CAP_SIG a where rownum < 500001


call     count       cpu    elapsed       disk      query    current
rows
------- ------  -------- ---------- ---------- ---------- ----------
----------
Parse        1      0.00       0.00          0          0
0           0
Execute      1      0.01       0.00          0          0
0           0
Fetch        2      0.60       2.01      10833      10847
0           1
------- ------  -------- ---------- ---------- ---------- ----------
----------
total        4      0.61       2.02      10833      10847
0           1

  Event waited on                             Times   Max. Wait  Total
Waited
  ----------------------------------------   Waited  ----------
------------
  SQL*Net message to client                       3        0.00
0.00
  SQL*Net message from client                     3       21.58
21.59
  library cache pin                               1        0.00
0.00
  row cache lock                                  4        0.00
0.00
  rdbms ipc reply                                 1        0.00
0.00
  db file sequential read                         1        0.01
0.01
*  i/o slave wait                                677        0.03
1.10
  db file scattered read                        677        0.03
1.16*
  gc cr multi block request                     527        0.00
0.39
  gc current grant 2-way                         10        0.00
0.00


select /*+ full(a) */ *
from
admksk.qos_jpo a where rownum < 500001


call     count       cpu    elapsed       disk      query    current
rows
------- ------  -------- ---------- ---------- ---------- ----------
----------
Parse        1      0.00       0.00          0          0
0           0
Execute      1      0.00       0.00          0          0
0           0
Fetch    33335      9.24      21.93      54240      83659          0
500000
------- ------  -------- ---------- ---------- ---------- ----------
----------
total    33337      9.24      21.94      54240      83659          0
500000

  Event waited on                             Times   Max. Wait  Total
Waited
  ----------------------------------------   Waited  ----------
------------
  SQL*Net message to client                   33335        0.00
0.00
  gc cr grant 2-way                               1        0.00
0.00
  db file sequential read                         4        0.00
0.00
  gc cr multi block request                    2731        0.00
1.96
*  i/o slave wait                               3390        0.04
11.25
  db file scattered read                       3390        0.04
11.56*
  SQL*Net message from client                 33335        0.00
3.90
  SQL*Net more data to client                186934        0.00
3.11



There is a bug introduced with 10.2.0.5, Bug 9772888 but seems to me is not
a performance bug, rather it generates more trace than usual (at least in
Solaris since AIO is dynamic). Anyone faced this issue :-?

Or this bug actually slows down the queries?

Thanks

Alex

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