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Oracle Tips by Burleson |
Shared Pool
The next section of the AWRRPTreport
deals with the SHARED pool, JAVA pooland
buffer statistics. This rseport section is shown in the following
listing:
Shared Pool
Advisory DB/Inst: SSD/ssd2 Snap: 4
-> SP: Shared
Pool Est LC: Estimated Library Cache Factr: Factor
-> Note there is
often a 1:Many correlation between a single logical object
in the
Library Cache, and the physical number of memory objects associated
with it.
Therefore comparing the number of Lib Cache objects (e.g. in
v$librarycache), with the number of Lib Cache Memory Objects is
invalid.
Est LC Est LC Est LC Est LC
Shared SP
Est LC Time Time Load Load Est LC
Pool
Size Size Est LC Saved Saved Time Time Mem
Size(M) Factr
(M) Mem Obj (s) Factr (s) Factr Obj Hits
------- -----
-------- ----------- ------- ------ ------- ------ -----------
76
.3 13 1,954 12 1.0 6 1.0 15,331
104
.4 13 1,954 12 1.0 6 1.0 15,331
132
.5 13 1,954 12 1.0 6 1.0 15,331
160
.7 13 1,954 12 1.0 6 1.0 15,331
188
.8 13 1,954 12 1.0 6 1.0 15,331
216
.9 13 1,954 12 1.0 6 1.0 15,331
244
1.0 13 1,954 12 1.0 6 1.0 15,331
272
1.1 13 1,954 12 1.0 6 1.0 15,331
300
1.2 13 1,954 12 1.0 6 1.0 15,331
328
1.3 13 1,954 12 1.0 6 1.0 15,331
356
1.5 13 1,954 12 1.0 6 1.0 15,331
384
1.6 13 1,954 12 1.0 6 1.0 15,331
412
1.7 13 1,954 12 1.0 6 1.0 15,331
440
1.8 13 1,954 12 1.0 6 1.0 15,331
468
1.9 13 1,954 12 1.0 6 1.0 15,331
496
2.0 13 1,954 12 1.0 6 1.0 15,331
-------------------------------------------------------------
Java Pool
Advisory DB/Inst: SSD/ssd2 Snap: 4
No data exists for this section of the report.
-------------------------------------------------------------
Buffer Wait
Statistics DB/Inst: SSD/ssd2 Snaps: 3-4
-> ordered by
wait time desc, waits desc
Class Waits Total Wait Time (s) Avg Time (ms)
------------------ ----------- ------------------- --------------
data
block 1,304 28 22
undo
header 356 2 4
undo
block 195 1 4
1st level bmb
4 0 0
system undo
header 1 0 0
-------------------------------------------------------------
In this section, it appears that the SHARED pool is
possibly over allocated for this database. From a review of the
advisory section and the heading section back in the first report
listing in this section, the memory assigned to the SHARED pool is not
being fully used, and the JAVA pool is not being
used at all.
The section of the above listing dealing with the
Buffer Wait Statisticsindicates
a need to see why transactions are holding on to blocks as the
data block waits
are most likely due to transaction
issues. The next section, the enqueuereport, will shine
some light on the possible causes of the
data block buffer waits
The
above book excerpt is from:
Oracle
Solid State Disk Tuning
High Performance Oracle
tuning with RAM disk
ISBN
0-9744486-5-6
Donald K. Burleson & Mike Ault
http://www.rampant-books.com/book_2005_1_ssd.htm
 |
For more details and scripts, see my new book "
Oracle
Tuning: The Definitive Reference", over 900 pages
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instant access to the code depot. |
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