Top five events
Hi,
may i know wat are the most top five events we often expect in statspack.
With Regards
Boo
top five wait events
C.
Similar Messages
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Today was our payroll day so the database was busy. And here are three different snaps - in the morning around midday and early afternoon.
CPU time figures in all of them, and in the first report there is an elapsed time of 51.45 from the SQL*Net more data from dblink metric. None of our users complain of long wait times and I dont see anything here to drill down to as I read that CPU time often appears in the Top 5. The only issue I can see here maybe is the SQL*Net metric.
Event Waits Time(s) Ela Time
SQL*Net more data from dblink 209 167 51.45
CPU time 69 21.20
db file sequential read 33,174 43 13.14
SQL*Net message from dblink 115 35 10.88
db file scattered read 6,775 6 1.73
Event Waits Time(s) Ela Time
CPU time 307 52.15
db file sequential read 493,485 173 29.49
SQL*Net message from dblink 154,908 40 6.75
latch free 996 25 4.33
db file scattered read 47,175 25 4.32
Event Waits Time(s) Ela Time
CPU time 87 63.80
db file sequential read 71,643 26 19.02
db file scattered read 18,309 14 10.53
control file parallel write 321 4 2.87
log file sequential read 16 2 1.18
nullYes - Oracle 9 on UNIX.
The snapshot period ws just over 10 minutes. We use 6 CPUs.
Load Profile
~~~~~~~~~~~~ Per Second Per Transaction
Redo size: 15,211.60 9,554.00
Logical reads: 12,538.50 7,875.11
Block changes: 94.62 59.43
Physical reads: 350.80 220.33
Physical writes: 5.06 3.18
User calls: 71.49 44.90
Parses: 43.67 27.43
Hard parses: 0.95 0.60
Sorts: 31.14 19.56
Logons: 0.11 0.07
Executes: 139.41 87.56
Transactions: 1.59
% Blocks changed per Read: 0.75 Recursive Call %: 85.21
Rollback per transaction %: 9.73 Rows per Sort: 7.03
Instance Efficiency Percentages (Target 100%)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Buffer Nowait %: 100.00 Redo NoWait %: 100.00
Buffer Hit %: 97.23 In-memory Sort %: 100.00
Library Hit %: 99.25 Soft Parse %: 97.83
Execute to Parse %: 68.68 Latch Hit %: 99.99
Parse CPU to Parse Elapsd %: 51.57 % Non-Parse CPU: 92.77
Shared Pool Statistics Begin End
Memory Usage %: 90.09 90.30
% SQL with executions>1: 90.51 91.39
% Memory for SQL w/exec>1: 86.61 87.37
Top 5 Timed Events
~~~~~~~~~~~~~~~~~~ % Total
Event Waits Time (s) Ela Time
CPU time 87 63.80
db file sequential read 71,643 26 19.02
db file scattered read 18,309 14 10.53
control file parallel write 321 4 2.87
log file sequential read 16 2 1.18
------------------------------------------------------------- -
Hi,
may i know wat are the most top five events we often expect in statspack.On a healthy system, physical read waits should be the biggest waits after the idle waits. However, also consider whether there are direct read waits (signifying full table scans with parallel query) or db file scattered read waits on an operational (OLTP) system that should be doing small indexed accesses.
http://download-west.oracle.com/docs/cd/B19306_01/server.102/b14211/instance_tune.htm#sthref863 -
How can I create a view of top five teams averages based on individual averages of that team?
I have created a list that groups teams by their Team name (Team column) with the individuals members (participants column) averages and their team average (total average view option). I want to only display the top five teams that have the overall
top team averages. I have a list that contains a team name, average minutes, week, and participant. The team manager plugs in each week a new entry for each participant on the team. I have a view that computes each team average but I want a view
of the top five teams based on the top averages of the team (not individual participant average). Unfortunately, I can only seem to get all teams grouped with individuals of that team, their individual averages and the team average but can't figure out
only how to show the top five teams top average. Because it's a total (team average) and not a separate column, I can't get a view by team based on total average. I can by top individual average but not by the team. Can some one help me figure
out a solution?A calculated column won't work because a calculated column can only reference the individual item, not the entire list or a subset.
You could do javascript to build this, but to me it's easier to just use Excel.
Andy Wessendorf | Solution Foundry [email protected] -
Understanding statspack report(CPU time in top time events)
Hi,
I am using oracle 9.2.0.8 RAC on SUN solaris platform.I am trying to understand my DB statistics using the below statspack report.Can you please coment on the below report
My quetions/thoughts are:
1) CPU time is in the top timed events,Is that eman some need to do with CPU increase.Was CPU bottleneck?
2) Parse CPU to Parse Elapsd %: 80.28 .Is this means I am hard parsing most of the time.How can identify which queries doing more hard parses.what is mean by% Non-Parse CPU: 98.76
3) Memory Usage %: 96.25 96.64.It seems to be there is too much memory usage.Can you elaborate this usage about what could be the reasons for this to happen
4) global cache cr request is coming in the top wait evetns and top timed events.Is there some issue with RAC?
5) can you please explain about 5 CR Blocks Served (RAC) and 5 CU Blocks Served (RAC) and Top 5 ITL Waits per
Your help is appreciated!!
Load Profile
~~~~~~~~~~~~ Per Second Per Transaction
Redo size: 2,101,521.49 18,932.15
Logical reads: 91,525.82 824.54
Block changes: 6,720.68 60.55
Physical reads: 5,644.92 50.85
Physical writes: 464.97 4.19
User calls: 922.79 8.31
Parses: 342.37 3.08
Hard parses: 1.52 0.01
Sorts: 324.18 2.92
Logons: 2.66 0.02
Executes: 2,131.75 19.20
Transactions: 111.00
% Blocks changed per Read: 7.34 Recursive Call %: 78.48
Rollback per transaction %: 22.43 Rows per Sort: 15.89
Instance Efficiency Percentages (Target 100%)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Buffer Nowait %: 99.66 Redo NoWait %: 100.00
Buffer Hit %: 93.86 In-memory Sort %: 100.00
Library Hit %: 99.95 Soft Parse %: 99.56
Execute to Parse %: 83.94 Latch Hit %: 99.79
Parse CPU to Parse Elapsd %: 80.28 % Non-Parse CPU: 98.76
Shared Pool Statistics Begin End
Memory Usage %: 96.25 96.64
% SQL with executions>1: 34.19 32.67
% Memory for SQL w/exec>1: 39.87 40.47
Top 5 Timed Events
~~~~~~~~~~~~~~~~~~ % Total
Event Waits Time (s) Ela Time
CPU time 10,406 42.54
db file sequential read 1,707,372 4,282 17.51
global cache cr request 2,566,822 2,369 9.68
db file scattered read 1,109,892 1,719 7.03
SQL*Net break/reset to client 17,287 1,348 5.51
Wait Events for DB: Instance:
-> s - second
-> cs - centisecond - 100th of a second
-> ms - millisecond - 1000th of a second
-> us - microsecond - 1000000th of a second
-> ordered by wait time desc, waits desc (idle events last)
Avg
Total Wait wait Waits
Event Waits Timeouts Time (s) (ms) /txn
db file sequential read 1,707,372 0 4,282 3 8.5
global cache cr request 2,566,822 3,356 2,369 1 12.8
db file scattered read 1,109,892 0 1,719 2 5.5
SQL*Net break/reset to clien 17,287 0 1,348 78 0.1
buffer busy waits 312,198 11 1,082 3 1.6
Message was edited by:
user509266This statspack taken for 30 minutes interval.We have 16 CPU's.We never got ORA-4031 errors.It means you have 16 * 30 * 60 = 28,800 seconds CPU available during the interval but you only used 10,406. So you don't have a CPU problem.
For Statspack documentation, you can have a look to <ORACLE_HOME>/rdbms/admin/spdoc.txt, Metalink note 228913.1, Jonathan Lewis Scratchpad, books commended by Rajesh Kumar Yogi and also to http://www.oracle.com/technology/deploy/performance/index.html -
Dear Support,
I run the AWR report. It show the top 5 event is class slave wait 70second then follow by CPU time. May i know what is class slave wait event. Thanks
Regard
William10g is a marketing label not a version number.
SELECT * FROM v$version;Don't describe the AWR report part your are seeing ... Ctrl-C then Ctrl-V ... and post it between tags so we can read it. -
Finding top five number in an array of arraylists.
I have to write a method with a heading
public static int [] findTopFiveMostSteps ( ArrayList [] temp )i will input an array of arraylists, and I have to write this method
that will return a integer array containing the top five number in that
array of arraylists.
I have no idea how to go on about this
please helpHow would you do it "manually"? That is, if you just
had pencil and paper and several lists of numbers,
what would be the steps? Keep them very simple and
precise.Socrates would be so proud.
I was just reminiscing about how I once tried to teach Java to the web designer
at my last job. I gave him the task of writing:
static int max(int[] values) He just didn't grok it:
Me: How would you figure it out by hand?
WD: I'd look at the numbers and pick the biggest.
Me: Break that down into steps.
WD: I'd -- look -- at -- the -- numbers -- and -- pick -- the -- biggest.
In the end, we tacitly agreed to stop the teaching and hope the manager didn't notice. -
how we can select top five records of sal column from emp table.
http://forums.oracle.com/forums/ann.jspa?annID=599
PL/SQL -
AV - Top Five Audit Sources by Number of Alerts - INTERNAL ERROR
Hi again!
We have one problem with audit vault console while connecting with auditor role.
There's one strange problem that occurs intermitently when clicking on "Top Five Audit Sources by Number of Alerts " graph on audit vault home page.
Sometimes it works perfectly and maybe next time it produces an internal error. It does not follow any logic. Maybe it works 1,2,3,... times and next one it doesn't and the links carriess you to an empty page with "INTERNAL ERROR" message.
It is something related with the url.
When you place the mouse coursor on the graph you can see the url at the bottom of internet explorer/firefox.
It's something like this: (it works)
http://<av hostname>:5707/av/console/database/avt/:::::P2_REPORT_TYPE,P2_DATE_TYPE,P2_SOURCE:WARNING_ALERT,DAY,<source name>
then you continue working come back to home page and place the cursor again on it. Then sometimes you see the same url(all it's going to work) or the next one:
http://<av hostname>:5700/av/console/database/avt/:::::P2_REPORT_TYPE,P2_DATE_TYPE,P2_SOURCE:WARNING_ALERT,DAY,<source name>
As you can see port number has changed misteriously... and it does not work.
The strange thing is that after the error i try to open a new auditor session with another explorer and it some times it works!!! until same thing happens.
Has anyone seen anything like this????? I don't know if it something about Audit Vault configuration, a bug or an internet explorer configuration issue.
i've tried different languages with my explorers and it continues happening ...
All the rest of the parts of the application work perfectly
Thanks!Whenever posting here ALWAYS include full version number.
Whenever posting an error post the full and complete error message (not your interpretation of it). "INTERNAL ERROR" in and of itself is meaningless.
I would suggest that you open an SR at metalink. -
hi,
pls I have this issue that needs to be resolved. I need to select top five rows from a table depending on the values of a column stock_value. pls I will appreciate if someone can help me out, Francois pls try and help
This is the senerio:
I have a table stock, on the table I have company_name, stock_value, sector.
Now I want to get top five rows from this table depending on the five highest value of stock_value and for each sector.
lets try and write a query that will retrive the records after that I will put it in a procedure.
I know am suppose to ask this on mssql forum but most mssql forums takes time to reply and this is very urgent cos I have to deliver in 45 minutes time
thank you very much
jideoforhy,
try out:
select s.name, sp. sp_sales total_sales
from salesperson s,
(select salesperson_id,sum(tot_sales) sp_sales
RANK() OVER (ORDER BY SUM(tot_SALES) desc) SALES_RANK
FROM ORDERS
WHERE YEAR = 2006
group by salesperson_id) sp
where sp.sales_rank <= 5 (...n)
and sp.salesperson_id = s.salesperson_id
order by sq.sales_rank;
give result in:
name total_sales
a 100
b 90
c 80
d 70
e 60
hope help you
regards -
How to top five minutes and ten minutes record
Hi,
i have to get top five minutes records
group by hostid and cpuid and timestamp is the field
group by
hostid,cpuid
and the group is also based on last 5 minutes or ten minutes or one day
select wait, idle, users, system ,wait+idle+users+system totalusers
from (select hostid,cpuid, avg(wait_to) wait, avg(idle) idle, avg(users) users, avg(system) system from system_cpu where hostid='DSCP02469' and cpuid='first'
group by cpuid,hostid having
max(timestamp)-timestamp<5/1440))
please correct it and send
with regards
shannu sarma
Message was edited by:
user517983
Message was edited by:
user517983Hi,
SELECT uo.hostid,uo.cpuid,uo.timestamp FROM system_cpu uo
WHERE timestamp >= (SELECT MAX(timestamp)
FROM syStem_cpu uo2 WHERE uo2.cpuid ='cpu1' and uo2.hostid='DSCP02469') - (5 / (24 * 60))HOSTID CPUID
and i even trying in this way but i am not getting right results
hostid='DSCP02469' and cpuid='first'
but other result are also comming due to
som bad sub query.
select cpuid,hostid,timestamp from system_cpu sys where
exists (select hostid,cpuid from system_cpu
where hostid='DSCP02469' and cpuid='first'
having max(timestamp)-sys.timestamp<5/1440
group by hostid,cpuid)
SQL> /
CPUID HOSTID TIMESTAMP
first DSCP02469 29:jun:2006:18:33:01
second dscp02469 29:jun:2006:18:30:18
second dscp02469 29:jun:2006:18:31:04
second dscp02469 29:jun:2006:18:32:53
second dsc02469 29:jun:2006:18:37:36
second dscp02469 29:jun:2006:18:40:39
second dscp02469 29:jun:2006:18:41:26
second dscp02469 29:jun:2006:18:42:31
Message was edited by:
user517983
Message was edited by:
user517983 -
Oracle RAC 9i LMD library cache lock top wait event
We are experiencing the library cache lock as our top wait event. Even thought the box is currently idle, The Global Enqueue Service Daemon (LMD) is taking up CPU cycles. The background process is also logging to trace "skgxpdocon: warning outstanding accept handle count has reached new high water mark 245000".
Any help would be appreciated.
ThanksThere is a new patch for this - check out p4673610 on metalink. We have also experience the problem in 9.2.0.8.
-
Hi,
when i generate AWR report i found
db_file_sequential read.
db_file_scattered read.
Log file sync
busy buffer wait
How can i resolve the above wait events pls suggest me.Hi Srini,
you don't need to resolve anything because it's in the top-5 wait list in an AWR report. Like Tanel Poder puts it "don't let your AWR report tell you what your problem is".
In your case: db file sequential/scattered reads are disk I/O, that's perfectly normal for a database to be waiting on such events. However, you should check "top SQL by reads" to see if there are any statements that are causing a significant fraction of these reads.
Log file sync is normally related to frequent commits, but can have other causes as well. Much more information is needed to investigate.
Buffer busy wait indicates contention for hot blocks. If you want to reduce these events, you need to find the source of this contention, this is something AWR cannot tell you -- you have to turn to ASH and other high-resolution diagnostic tools instead.
However, a fact that an event made it to the top-5 list is not meaningful in itself. What % of database time is it consuming? Is it big enough to justify any tuning effort?
Best regards,
Nikolay -
Log file sequential read and RFS ping/write - among Top 5 event
I have situation here to discuss. In a 3-node RAC setup which is Logical standby DB; one node is showing high CPU utilization around 40~50%. The CPU utilization was less than 20% 10 days back but from 9th oldest day it jumped and consistently shows the double figure. I ran AWR reports on all three nodes and found one node with high CPU utilization and shows below tops events-
EVENT WAITS TIME(S) AVG WAIT(MS) %TOTAL CALL TIME WAIT CLASS
CPU time 5,802 34.9
RFS ping 15 5,118 33,671 30.8 Other
Log file sequential read 234,831 5,036 21 30.3 System I/O
Sql*Net more data from
client 24,171 1,087 45 6.5 Network
Db file sequential read 130,939 453 3 2.7 User I/O
Findings:-
On AWR report(file attached) for node= sipd207; we can see that "RFS PING" wait event takes 30% of the waits and "log file sequential read" wait event takes 30% of the waits that occurs in database.
Environment :- (Oracle- 10.2.0.4.0, O/S - AIX .3)
1)other node awr shows "log file sync" - is it due to oversized log buffer?
2)Network wait events can be reduced by tweaking SDU & TDU values based on MDU.
3) Why ARCH processes taking much to archives filled redo logs; is it issue with slow disk I/O?
Regards
WORKLOAD REPOSITORY report for<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<DB Name DB Id Instance Inst Num Release RAC Host
XXXPDB 4123595889 XXX2p2 2 10.2.0.4.0 YES sipd207
Snap Id Snap Time Sessions Curs/Sess
Begin Snap: 1053 04-Apr-11 18:00:02 59 7.4
End Snap: 1055 04-Apr-11 20:00:35 56 7.5
Elapsed: 120.55 (mins)
DB Time: 233.08 (mins)
Cache Sizes
~~~~~~~~~~~ Begin End
Buffer Cache: 3,728M 3,728M Std Block Size: 8K
Shared Pool Size: 4,080M 4,080M Log Buffer: 14,332K
Load Profile
~~~~~~~~~~~~ Per Second Per Transaction
Redo size: 245,392.33 10,042.66
Logical reads: 9,080.80 371.63
Block changes: 1,518.12 62.13
Physical reads: 7.50 0.31
Physical writes: 44.00 1.80
User calls: 36.44 1.49
Parses: 25.84 1.06
Hard parses: 0.59 0.02
Sorts: 12.06 0.49
Logons: 0.05 0.00
Executes: 295.91 12.11
Transactions: 24.43
% Blocks changed per Read: 16.72 Recursive Call %: 94.18
Rollback per transaction %: 4.15 Rows per Sort: 53.31
Instance Efficiency Percentages (Target 100%)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Buffer Nowait %: 99.99 Redo NoWait %: 100.00
Buffer Hit %: 99.92 In-memory Sort %: 100.00
Library Hit %: 99.83 Soft Parse %: 97.71
Execute to Parse %: 91.27 Latch Hit %: 99.79
Parse CPU to Parse Elapsd %: 15.69 % Non-Parse CPU: 99.95
Shared Pool Statistics Begin End
Memory Usage %: 83.60 84.67
% SQL with executions>1: 97.49 97.19
% Memory for SQL w/exec>1: 97.10 96.67
Top 5 Timed Events Avg %Total
~~~~~~~~~~~~~~~~~~ wait Call
Event Waits Time (s) (ms) Time Wait Class
CPU time 4,503 32.2
RFS ping 168 4,275 25449 30.6 Other
log file sequential read 183,537 4,173 23 29.8 System I/O
SQL*Net more data from client 21,371 1,009 47 7.2 Network
RFS write 25,438 343 13 2.5 System I/O
RAC Statistics DB/Inst: UDAS2PDB/udas2p2 Snaps: 1053-1055
Begin End
Number of Instances: 3 3
Global Cache Load Profile
~~~~~~~~~~~~~~~~~~~~~~~~~ Per Second Per Transaction
Global Cache blocks received: 0.78 0.03
Global Cache blocks served: 1.18 0.05
GCS/GES messages received: 131.69 5.39
GCS/GES messages sent: 139.26 5.70
DBWR Fusion writes: 0.06 0.00
Estd Interconnect traffic (KB) 68.60
Global Cache Efficiency Percentages (Target local+remote 100%)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Buffer access - local cache %: 99.91
Buffer access - remote cache %: 0.01
Buffer access - disk %: 0.08
Global Cache and Enqueue Services - Workload Characteristics
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Avg global enqueue get time (ms): 0.5
Avg global cache cr block receive time (ms): 0.9
Avg global cache current block receive time (ms): 1.0
Avg global cache cr block build time (ms): 0.0
Avg global cache cr block send time (ms): 0.1
Global cache log flushes for cr blocks served %: 2.9
Avg global cache cr block flush time (ms): 4.6
Avg global cache current block pin time (ms): 0.0
Avg global cache current block send time (ms): 0.1
Global cache log flushes for current blocks served %: 0.1
Avg global cache current block flush time (ms): 5.0
Global Cache and Enqueue Services - Messaging Statistics
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Avg message sent queue time (ms): 0.1
Avg message sent queue time on ksxp (ms): 0.6
Avg message received queue time (ms): 0.0
Avg GCS message process time (ms): 0.0
Avg GES message process time (ms): 0.1
% of direct sent messages: 31.57
% of indirect sent messages: 5.17
% of flow controlled messages: 63.26
Time Model Statistics DB/Inst: UDAS2PDB/udas2p2 Snaps: 1053-1055
-> Total time in database user-calls (DB Time): 13984.6s
-> Statistics including the word "background" measure background process
time, and so do not contribute to the DB time statistic
-> Ordered by % or DB time desc, Statistic name
Statistic Name Time (s) % of DB Time
sql execute elapsed time 7,270.6 52.0
DB CPU 4,503.1 32.2
parse time elapsed 506.7 3.6
hard parse elapsed time 497.8 3.6
sequence load elapsed time 152.4 1.1
failed parse elapsed time 19.5 .1
repeated bind elapsed time 3.4 .0
PL/SQL execution elapsed time 0.7 .0
hard parse (sharing criteria) elapsed time 0.3 .0
connection management call elapsed time 0.3 .0
hard parse (bind mismatch) elapsed time 0.0 .0
DB time 13,984.6 N/A
background elapsed time 869.1 N/A
background cpu time 276.6 N/A
Wait Class DB/Inst: UDAS2PDB/udas2p2 Snaps: 1053-1055
-> s - second
-> cs - centisecond - 100th of a second
-> ms - millisecond - 1000th of a second
-> us - microsecond - 1000000th of a second
-> ordered by wait time desc, waits desc
Avg
%Time Total Wait wait Waits
Wait Class Waits -outs Time (s) (ms) /txn
System I/O 529,934 .0 4,980 9 3.0
Other 582,349 37.4 4,611 8 3.3
Network 279,858 .0 1,009 4 1.6
User I/O 54,899 .0 317 6 0.3
Concurrency 136,907 .1 58 0 0.8
Cluster 60,300 .0 41 1 0.3
Commit 80 .0 10 130 0.0
Application 6,707 .0 3 0 0.0
Configuration 17,528 98.5 1 0 0.1
Wait Events DB/Inst: UDAS2PDB/udas2p2 Snaps: 1053-1055
-> s - second
-> cs - centisecond - 100th of a second
-> ms - millisecond - 1000th of a second
-> us - microsecond - 1000000th of a second
-> ordered by wait time desc, waits desc (idle events last)
Avg
%Time Total Wait wait Waits
Event Waits -outs Time (s) (ms) /txn
RFS ping 168 .0 4,275 25449 0.0
log file sequential read 183,537 .0 4,173 23 1.0
SQL*Net more data from clien 21,371 .0 1,009 47 0.1
RFS write 25,438 .0 343 13 0.1
db file sequential read 54,680 .0 316 6 0.3
DFS lock handle 97,149 .0 214 2 0.5
log file parallel write 104,808 .0 157 2 0.6
db file parallel write 143,905 .0 149 1 0.8
RFS random i/o 25,438 .0 86 3 0.1
RFS dispatch 25,610 .0 56 2 0.1
control file sequential read 39,309 .0 55 1 0.2
row cache lock 130,665 .0 47 0 0.7
gc current grant 2-way 35,498 .0 23 1 0.2
wait for scn ack 50,872 .0 20 0 0.3
enq: WL - contention 6,156 .0 14 2 0.0
gc cr grant 2-way 16,917 .0 11 1 0.1
log file sync 80 .0 10 130 0.0
Log archive I/O 3,986 .0 9 2 0.0
control file parallel write 3,493 .0 8 2 0.0
latch free 2,356 .0 6 2 0.0
ksxr poll remote instances 278,473 49.4 6 0 1.6
enq: XR - database force log 2,890 .0 4 1 0.0
enq: TX - index contention 325 .0 3 11 0.0
buffer busy waits 4,371 .0 3 1 0.0
gc current block 2-way 3,002 .0 3 1 0.0
LGWR wait for redo copy 9,601 .2 2 0 0.1
SQL*Net break/reset to clien 6,438 .0 2 0 0.0
latch: ges resource hash lis 23,223 .0 2 0 0.1
enq: WF - contention 32 6.3 2 62 0.0
enq: FB - contention 660 .0 2 2 0.0
enq: PS - contention 1,088 .0 2 1 0.0
library cache lock 869 .0 1 2 0.0
enq: CF - contention 671 .1 1 2 0.0
gc current grant busy 1,488 .0 1 1 0.0
gc current multi block reque 1,072 .0 1 1 0.0
reliable message 618 .0 1 2 0.0
CGS wait for IPC msg 62,402 100.0 1 0 0.4
gc current block 3-way 998 .0 1 1 0.0
name-service call wait 18 .0 1 57 0.0
cursor: pin S wait on X 78 100.0 1 11 0.0
os thread startup 16 .0 1 53 0.0
enq: RO - fast object reuse 193 .0 1 3 0.0
IPC send completion sync 652 99.2 1 1 0.0
local write wait 194 .0 1 3 0.0
gc cr block 2-way 534 .0 0 1 0.0
log file switch completion 17 .0 0 20 0.0
SQL*Net message to client 258,483 .0 0 0 1.5
undo segment extension 17,282 99.9 0 0 0.1
gc cr block 3-way 286 .7 0 1 0.0
enq: TM - contention 76 .0 0 4 0.0
PX Deq: reap credit 15,246 95.6 0 0 0.1
kksfbc child completion 5 100.0 0 49 0.0
enq: TT - contention 141 .0 0 2 0.0
enq: HW - contention 203 .0 0 1 0.0
RFS create 2 .0 0 115 0.0
rdbms ipc reply 339 .0 0 1 0.0
PX Deq Credit: send blkd 452 20.1 0 0 0.0
gcs log flush sync 128 32.8 0 2 0.0
latch: cache buffers chains 128 .0 0 1 0.0
library cache pin 441 .0 0 0 0.0
Wait Events DB/Inst: UDAS2PDB/udas2p2 Snaps: 1053-1055
-> s - second
-> cs - centisecond - 100th of a second
-> ms - millisecond - 1000th of a second
-> us - microsecond - 1000000th of a second
-> ordered by wait time desc, waits desc (idle events last)We only apply on one node in a cluster so I would expect that the node running SQL Apply would have much higher usage and waits. Is this what you are asking?
Larry -
hi gurus,
3 node rac 10.2.0.4 serving a packaged application.
Top 5 timed events in awr shown as
Event=CPU time
Waits=
Time(s)=1,950
Avg Wait(ms)
% Total Call Time=45.3
Wait Class
Event=gc cr multi block request
Waits= 6,551,055
Time(s)= 1,396
Avg Wait(ms)=0
% Total Call Time=38.9
Wait Class= Cluster
Event=db file scattered read
Waits= 186,295
Time(s)= 719
Avg Wait(ms)=4
% Total Call Time=18.2
Wait Class= User I/O
Event=db file parallel read
Waits= 43,383
Time(s)= 241
Avg Wait(ms)=6
% Total Call Time= 5.9
Wait Class= User I/O
Event= log file sync
Waits= 71,064
Time(s)= 83
Avg Wait(ms)=1
% Total Call Time= 3.1
Wait Class= Commit
db_block_size=8KB
db_file_multiblock_read_count = default setting of 128
question:
are the high wait values of gc cr multi block request and db file scattered read are due to db_file_multiblock_read_count?
if that's the case, is there a way to find optimum value for db_file_multiblock_read_count?
or any other findings please?
experts, appreciate your valuable help
thanks in advance,
charlesuser570138 wrote:
there are queries going for the full table scan with outer joins (milliion of records). those are the same sqls at the top of "sql order by cluster time"in awr with high CPU utilization.
any way to fine tune the instance to reduce the "gc cr multi block request"
apart from changing the code as the code belongs to a package based application please?
Do you have a performance problem ?
You are doing some large tablescans; these are (probably) the root cause of the gc cr multiblock read, the db file scattered reads, and the CPU, but if the queries are necessary and the execution paths are the best that can be done then maybe you just have to recognise that the resource you're using is reasonable for the queries you have to run.
Otherwise
<ul>
(a) can you find a more efficient access path for any of these queries
(b) can you make sure that all these queries run on the same node so that you get some benefit from node-affinity (possibly the object(s) will be remasted to that single node) and reduce the interconnect traffic.
</ul>
Regards
Jonathan Lewis
http://jonathanlewis.wordpress.com
http://www.jlcomp.demon.co.uk
To post code, statspack/AWR report, execution plans or trace files, start and end the section with the tag {noformat}{noformat} (lowercase, curly brackets, no spaces) so that the text appears in fixed format.
"Science is more than a body of knowledge; it is a way of thinking"
Carl Sagan
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