10.2.0.3 high concurrency wait event
I have a new 64bit windows 10g 10.2.0.3 VM server doing nothing but spinning its wheels. I intalled Oracle on it Friday and when I checked it tonight I see it is getting high concurrency wait events. Looks like every 10 minutes concurrency goes up to about 35.0 (?seconds) and then goes back to 0 - up and down every few minutes. Just enough to hit the warning threashold.
I need this machine for a peoplesoft install on Monday morning.
Anyone have any ideas what this could be? I kinda know what concurrency is but not sure if it could be from hardware or software.
Didn't see any patches/bugs but I will continue to look.
Help, Kathie
What are the wait events as described in v$system_wait and v$session_event?
Similar Messages
-
Concurrency wait on an insert statement
Hello All,
I am running Oracle RAC 2 nodes 11g R2 on AIX 7.1
I have a table with unique index, and the application is doing inserts/updates into this table.
Suddenly and for about half a minute I faced a high concurrency waits on all the processes running these inserts for one node. I saw this high concurrency wait in the top activity screen of the OEM only on one of the nodes. knowing that the processes doing these inserts are running on both nodes.
All what I have that in this half minute I see high concurrency wait in OEM top activity screen related to this insert statement and when I clicked on the insert I found high "enq: TX - index contention". Again this was only on one node.
After this half minute everything went back to normal.
What could be the reason and how can I investigate it ?
Regards,Neo-b wrote:
Hello All,
I am running Oracle RAC 2 nodes 11g R2 on AIX 7.1
I have a table with unique index, and the application is doing inserts/updates into this table.
Suddenly and for about half a minute I faced a high concurrency waits on all the processes running these inserts for one node. I saw this high concurrency wait in the top activity screen of the OEM only on one of the nodes. knowing that the processes doing these inserts are running on both nodes.
All what I have that in this half minute I see high concurrency wait in OEM top activity screen related to this insert statement and when I clicked on the insert I found high "enq: TX - index contention". Again this was only on one node.
After this half minute everything went back to normal.
What could be the reason and how can I investigate it ?
Regards,I bet that the INDEX contains a SEQUENCE. -
High Database Waits of type "other"
I justed added cpu patch 19 to my 11.1.0.7 windows 2008 database. Now I have a large amount of database waiting of type "other". See below.
Investigate the cause for high "unspecified wait event" waits. Refer to Oracle's "Database Reference" for the description of this wait event.
Action Investigate the cause for high "unspecified wait event" waits in Service "SYS$USERS".
Action Investigate the cause for high "unspecified wait event" waits in Module "DBMS_SCHEDULER"
Could stale statistics cause this and if so what is the correct way to gather system statistics. Do I unlock sys schema , gather data dictionary stats, and then lock sys schema?
Other thoughts what might cause this?
Thanks,
KathieHi,
You should run the following.
DBMS_STATS.GATHER_SYSTEM_STATS (
gathering_mode VARCHAR2 DEFAULT 'NOWORKLOAD',
interval INTEGER DEFAULT NULL,
stattab VARCHAR2 DEFAULT NULL,
statid VARCHAR2 DEFAULT NULL,
statown VARCHAR2 DEFAULT NULL);
dbms_stats.gather_system_stats(gathering_mode=>'start');
dbms_stats.gather_system_stats(gathering_mode=>'stop');
System statistics will start gathering afetr you run the command with start option. System stats gathering will stop and may show them locked after you run stop.
NOWORKLOAD: Will capture characteristics of the I/O system. Gathering may take a few minutes and depends on the size of the database. During this period Oracle will estimate the average read seek time and transfer speed for the I/O system. This mode is suitable for the all workloads. Oracle recommends to run GATHER_SYSTEM_STATS ('noworkload') after creation of the database and tablespaces. To fine tune system statistics for the workload use 'START' and 'STOP' or 'INTERVAL' options. If you gather both 'NOWORKLOAD' and workload specific (statistics collected using 'INTERVAL' or 'START' and 'STOP' ), the workload statistics will be used by optimizer. Collected components: cpuspeednw, ioseektim, iotfrspeed.
INTERVAL: Captures system activity during a specified interval. This works in combination with the interval parameter. You should provide an interval value in minutes, after which system statistics are created or updated in the dictionary or stattab. You can use GATHER_SYSTEM_STATS (gathering_mode=>'STOP') to stop gathering earlier than scheduled. Collected components: maxthr, slavethr, cpuspeed, sreadtim, mreadtim, mbrc.
START | STOP: Captures system activity during specified start and stop times and refreshes the dictionary or stattab with statistics for the elapsed period. Interval value is ignored. Collected components: maxthr, slavethr, cpuspeed, sreadtim, mreadtim, mbrc.
interval
Time, in minutes, to gather statistics. This parameter applies only when gathering_mode='INTERVAL'.
Regards -
High virtual circuit wait event
Hi,
in my 11g Enterprise Edition Database I have a problem with some sessions that are almost always in virtual circuit wait event. What is this wait event and how can I troubleshoot it?
IMPORTANT: I'm not using XDB or APEX
Edited by: Insaponata on Jan 9, 2011 8:00 AMFrom awr report based on the last our of work I see:
Top 5 Timed Foreground Events
Event Waits Time(s) Avg wait (ms) % DB time Wait Class
virtual circuit wait 95,038 16,056 169 263.91 Network
DB CPU 305 5.02
SQL*Net message from dblink 42,432 48 1 0.79 Network
db file sequential read 21,990 48 2 0.78 User I/O
db file scattered read 26,021 36 1 0.59 User I/O
Do you think that this situation is normal? If no, how can I troubleshoot? -
DB CPU wait event is high in AWR
Hello Experts,
Could you please tell me what are the causes of increasing DB CPU wait event ? I mentioned below which i know. please guide me
1. When Buffer cache is more than required then DB CPU wait event occur.
Regards,
SachinSachin.Ichake wrote:
Currently in my database DB CPU has taken 90% DB time . in accordance to resolve it I will gonna follow steps
1. Tune the query which has taken more cpu
2. Decrease Buffer cache size by referring buffer cache advisory.Solve what? You must understand that DB CPU is not shown as a Wait Event but as a Timed Event and so are the other events that are shown in the Top 5 Timed Events category. This is an indication of how much you have used in the comparison of the total DB Time but not necessarily , it's an issue as to do anything in the system, you would need to burn the CPU only. You need to check that how much total CPU time you have with you and then compare it with your DB CPU seconds. In addition to this, you also need to check the CPU consumption from the o/s commands like Top etc. Combining all of such information only would be able to help to understand that whether any tuning needs to be done or not.
Post here the AWR/Statspack report. That would give more clear picture of the things.
Aman.... -
Hi frnds,
As, I'm beginner to performance tuning I dont know
What action do i need to take?
I mean how to read the output which I given below.
this is the output suffering buffer busy waits.
Could anyone please tell me
CLASS TOTAL_WAITS TOTAL_TIME
data block 93303 58711
unused 0 0
system undo header 12 232
undo header 7847 6636
3rd level bmb 0 0
save undo header 0 0
bitmap index block 0 0
file header block 0 0
free list 0 0
undo block 68 207
segment header 422 399
extent map 0 0
2nd level bmb 0 0
system undo block 0 0
sort block 0 0
save undo block 0 0
1st level bmb 1 17
bitmap block 0 0
Thanks, Muhammed Thameem. SHello,
"Buffer busy waits" is contention for a buffer (representing a specific
version of a database block) within the Buffer Cache. So, in essence
it is block contention and thus it is most likely something to do with
the design of the tables and indexes supporting the application. A
built-in bottleneck. On indexes, it could be the age-old problem of
insertions into an index on a column with a monotonically-ascending
data value (i.e. timestamps or sequence numbers) which tends to cause
contention on the highest leaf node of the index. On tables, it might
have to do with many concurrent insertions into a table in a
freelist-managed tablespace where the table has only one freelist. It
could also be due to a home-grown implementation of sequence-number
generators (i.e. small table with one row, one column in which contains
the "last value" of a sequence, etc) which lots of people use to avoid
not being "portable across databases" which they think means not using
Oracle sequences (yadda yadda yadda).
I'd look for any SQL statement in the "SQL sorted by Elapsed Time"
section of the AWR report which exhibits high elapsed time but
relatively low CPU time, indicating a lot of wait time. Of course,
there are something like 800 possible wait events in current releases
of Oracle, of which "buffer busy waits" is only one, so this is just
inference and not a direct causal connection to your problem. But,
once I find such statements I'd check to see if they are
accessing/manipulating tables within the CUBS_DATA tablespace, and then
use "select * from table(dbms_xplan.display_awr('sql-id'))" to
get the execution plan(s), and then look for something ineffective
within the execution plan. You might find the script "sqlhistory.sql" helpful
here as well, to get a "historical perspective" on the execution of the
SQL statements over time, in case the buffer busy waits peaked at some
point in the past
Please refer to:
http://www.pubbs.net/201003/oracle/51925-understanding-awr-buffer-waits.html
Also
http://www.remote-dba.net/oracle_10g_tuning/t_buffer_busy_waits.htm
kind regards
Mohamed -
Wait Events "log file parallel write" / "log file sync" during CREATE INDEX
Hello guys,
at my current project i am performing some performance tests for oracle data guard. The question is "How does a LGWR SYNC transfer influences the system performance?"
To get some performance values, that i can compare i just built up a normal oracle database in the first step.
Now i am performing different tests like creating "large" indexes, massive parallel inserts/commits, etc. to get the bench mark.
My database is an oracle 10.2.0.4 with multiplexed redo log files on AIX.
I am creating an index on a "normal" table .. i execute "dbms_workload_repository.create_snapshot()" before and after the CREATE INDEX to get an equivalent timeframe for the AWR report.
After the index is built up (round about 9 GB) i perform an awrrpt.sql to get the AWR report.
And now take a look at these values from the AWR
Avg
%Time Total Wait wait Waits
Event Waits -outs Time (s) (ms) /txn
log file parallel write 10,019 .0 132 13 33.5
log file sync 293 .7 4 15 1.0
......How can this be possible?
Regarding to the documentation
-> log file sync: http://download.oracle.com/docs/cd/B19306_01/server.102/b14237/waitevents003.htm#sthref3120
Wait Time: The wait time includes the writing of the log buffer and the post.-> log file parallel write: http://download.oracle.com/docs/cd/B19306_01/server.102/b14237/waitevents003.htm#sthref3104
Wait Time: Time it takes for the I/Os to complete. Even though redo records are written in parallel, the parallel write is not complete until the last I/O is on disk.This was also my understanding .. the "log file sync" wait time should be higher than the "log file parallel write" wait time, because of it includes the I/O and the response time to the user session.
I could accept it, if the values are close to each other (maybe round about 1 second in total) .. but the different between 132 seconds and 4 seconds is too noticeable.
Is the behavior of the log file sync/write different when performing a DDL like CREATE INDEX (maybe async .. like you can influence it with the initialization parameter COMMIT_WRITE??)?
Do you have any idea how these values come about?
Any thoughts/ideas are welcome.
Thanks and RegardsSurachart Opun (HunterX) wrote:
Thank you for Nice Idea.
In this case, How can we reduce "log file parallel write" and "log file sync" waited time?
CREATE INDEX with NOLOGGINGA NOLOGGING can help, can't it?Yes - if you create index nologging then you wouldn't be generating that 10GB of redo log, so the waits would disappear.
Two points on nologging, though:
<ul>
it's "only" an index, so you could always rebuild it in the event of media corruption, but if you had lots of indexes created nologging this might cause an unreasonable delay before the system was usable again - so you should decide on a fallback option, such as taking a new backup of the tablespace as soon as all the nologging operatons had completed.
If the database, or that tablespace, is in +"force logging"+ mode, the nologging will not work.
</ul>
Don't get too alarmed by the waits, though. My guess is that the +"log file sync"+ waits are mostly from other sessions, and since there aren't many of them the other sessions are probably not seeing a performance issue. The +"log file parallel write"+ waits are caused by your create index, but they are happeninng to lgwr in the background which is running concurrently with your session - so your session is not (directly) affected by them, so may not be seeing a performance issue.
The other sessions are seeing relatively high sync times because their log file syncs have to wait for one of the large writes that you have triggered to complete, and then the logwriter includes their (little) writes with your next (large) write.
There may be a performance impact, though, from the pure volume of I/O. Apart from the I/O to write the index you have LGWR writting (N copies) of the redo for the index and ARCH is reading and writing the completed log files caused by the index build. So the 9GB of index could easily be responsible for vastly more I/O than the initial 9GB.
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 -
Hi: I'm analyzing this STATSPACK report: it is "volume test" on our UAT server, so most input is from 'bind variables'. Our shared pool is well utilized in oracle. Oracle redo logs is not appropriately configured on this server, as in 'Top 5 wait events' there are 2 for redos.
I need to know what else information can be dig-out from 'foreground wait events' & 'background wait events', and what can assist us to better understanding, in combination of 'Top 5 wait event's, that how the server/test went? it could be overwelming No. of wait events, so appreciate any helpful diagnostic or analysis. Database is oracle 11.2.0.4 upgraded from 11.2.0.3, on IBM AIX power system 64bit, level 6.x
STATSPACK report for
Database DB Id Instance Inst Num Startup Time Release RAC
~~~~~~~~ ----------- ------------ -------- --------------- ----------- ---
700000XXX XXX 1 22-Apr-15 12:12 11.2.0.4.0 NO
Host Name Platform CPUs Cores Sockets Memory (G)
~~~~ ---------------- ---------------------- ----- ----- ------- ------------
dXXXX_XXX AIX-Based Systems (64- 2 1 0 16.0
Snapshot Snap Id Snap Time Sessions Curs/Sess Comment
~~~~~~~~ ---------- ------------------ -------- --------- ------------------
Begin Snap: 5635 22-Apr-15 13:00:02 114 4.6
End Snap: 5636 22-Apr-15 14:00:01 128 8.8
Elapsed: 59.98 (mins) Av Act Sess: 0.6
DB time: 35.98 (mins) DB CPU: 19.43 (mins)
Cache Sizes Begin End
~~~~~~~~~~~ ---------- ----------
Buffer Cache: 2,064M Std Block Size: 8K
Shared Pool: 3,072M Log Buffer: 13,632K
Load Profile Per Second Per Transaction Per Exec Per Call
~~~~~~~~~~~~ ------------------ ----------------- ----------- -----------
DB time(s): 0.6 0.0 0.00 0.00
DB CPU(s): 0.3 0.0 0.00 0.00
Redo size: 458,720.6 8,755.7
Logical reads: 12,874.2 245.7
Block changes: 1,356.4 25.9
Physical reads: 6.6 0.1
Physical writes: 61.8 1.2
User calls: 2,033.7 38.8
Parses: 286.5 5.5
Hard parses: 0.5 0.0
W/A MB processed: 1.7 0.0
Logons: 1.2 0.0
Executes: 801.1 15.3
Rollbacks: 6.1 0.1
Transactions: 52.4
Instance Efficiency Indicators
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Buffer Nowait %: 100.00 Redo NoWait %: 100.00
Buffer Hit %: 99.98 Optimal W/A Exec %: 100.00
Library Hit %: 99.77 Soft Parse %: 99.82
Execute to Parse %: 64.24 Latch Hit %: 99.98
Parse CPU to Parse Elapsd %: 53.15 % Non-Parse CPU: 98.03
Shared Pool Statistics Begin End
Memory Usage %: 10.50 12.79
% SQL with executions>1: 69.98 78.37
% Memory for SQL w/exec>1: 70.22 81.96
Top 5 Timed Events Avg %Total
~~~~~~~~~~~~~~~~~~ wait Call
Event Waits Time (s) (ms) Time
CPU time 847 50.2
enq: TX - row lock contention 4,480 434 97 25.8
log file sync 284,169 185 1 11.0
log file parallel write 299,537 164 1 9.7
log file sequential read 698 16 24 1.0
Host CPU (CPUs: 2 Cores: 1 Sockets: 0)
~~~~~~~~ Load Average
Begin End User System Idle WIO WCPU
1.16 1.84 19.28 14.51 66.21 1.20 82.01
Instance CPU
~~~~~~~~~~~~ % Time (seconds)
Host: Total time (s): 7,193.8
Host: Busy CPU time (s): 2,430.7
% of time Host is Busy: 33.8
Instance: Total CPU time (s): 1,203.1
% of Busy CPU used for Instance: 49.5
Instance: Total Database time (s): 2,426.4
%DB time waiting for CPU (Resource Mgr): 0.0
Memory Statistics Begin End
~~~~~~~~~~~~~~~~~ ------------ ------------
Host Mem (MB): 16,384.0 16,384.0
SGA use (MB): 7,136.0 7,136.0
PGA use (MB): 282.5 361.4
% Host Mem used for SGA+PGA: 45.3 45.8
Foreground Wait Events DB/Inst: XXXXXs Snaps: 5635-5636
-> Only events with Total Wait Time (s) >= .001 are shown
-> ordered by Total Wait Time desc, Waits desc (idle events last)
Avg %Total
%Tim Total Wait wait Waits Call
Event Waits out Time (s) (ms) /txn Time
enq: TX - row lock contentio 4,480 0 434 97 0.0 25.8
log file sync 284,167 0 185 1 1.5 11.0
Disk file operations I/O 8,741 0 4 0 0.0 .2
direct path write 13,247 0 3 0 0.1 .2
db file sequential read 6,058 0 1 0 0.0 .1
buffer busy waits 1,800 0 1 1 0.0 .1
SQL*Net more data to client 29,161 0 1 0 0.2 .1
direct path read 7,696 0 1 0 0.0 .0
db file scattered read 316 0 1 2 0.0 .0
latch: shared pool 144 0 0 2 0.0 .0
CSS initialization 30 0 0 3 0.0 .0
cursor: pin S 10 0 0 9 0.0 .0
row cache lock 41 0 0 2 0.0 .0
latch: row cache objects 19 0 0 3 0.0 .0
log file switch (private str 8 0 0 7 0.0 .0
library cache: mutex X 28 0 0 2 0.0 .0
latch: cache buffers chains 54 0 0 1 0.0 .0
latch free 290 0 0 0 0.0 .0
control file sequential read 1,568 0 0 0 0.0 .0
log file switch (checkpoint 4 0 0 6 0.0 .0
direct path sync 8 0 0 3 0.0 .0
latch: redo allocation 60 0 0 0 0.0 .0
SQL*Net break/reset to clien 34 0 0 1 0.0 .0
latch: enqueue hash chains 45 0 0 0 0.0 .0
latch: cache buffers lru cha 7 0 0 2 0.0 .0
latch: session allocation 5 0 0 1 0.0 .0
latch: object queue header o 6 0 0 1 0.0 .0
ASM file metadata operation 30 0 0 0 0.0 .0
latch: In memory undo latch 15 0 0 0 0.0 .0
latch: undo global data 8 0 0 0 0.0 .0
SQL*Net message from client 6,362,536 0 278,225 44 33.7
jobq slave wait 7,270 100 3,635 500 0.0
SQL*Net more data from clien 7,976 0 15 2 0.0
SQL*Net message to client 6,362,544 0 8 0 33.7
Background Wait Events DB/Inst: XXXXXs Snaps: 5635-5636
-> Only events with Total Wait Time (s) >= .001 are shown
-> ordered by Total Wait Time desc, Waits desc (idle events last)
Avg %Total
%Tim Total Wait wait Waits Call
Event Waits out Time (s) (ms) /txn Time
log file parallel write 299,537 0 164 1 1.6 9.7
log file sequential read 698 0 16 24 0.0 1.0
db file parallel write 9,556 0 13 1 0.1 .8
os thread startup 146 0 10 70 0.0 .6
control file parallel write 2,037 0 2 1 0.0 .1
Log archive I/O 35 0 1 30 0.0 .1
LGWR wait for redo copy 2,447 0 0 0 0.0 .0
db file async I/O submit 9,556 0 0 0 0.1 .0
db file sequential read 145 0 0 2 0.0 .0
Disk file operations I/O 349 0 0 0 0.0 .0
db file scattered read 30 0 0 4 0.0 .0
control file sequential read 5,837 0 0 0 0.0 .0
ADR block file read 19 0 0 4 0.0 .0
ADR block file write 5 0 0 15 0.0 .0
direct path write 14 0 0 2 0.0 .0
direct path read 3 0 0 7 0.0 .0
latch: shared pool 3 0 0 6 0.0 .0
log file single write 56 0 0 0 0.0 .0
latch: redo allocation 53 0 0 0 0.0 .0
latch: active service list 1 0 0 3 0.0 .0
latch free 11 0 0 0 0.0 .0
rdbms ipc message 314,523 5 57,189 182 1.7
Space Manager: slave idle wa 4,086 88 18,996 4649 0.0
DIAG idle wait 7,185 100 7,186 1000 0.0
Streams AQ: waiting for time 2 50 4,909 ###### 0.0
Streams AQ: qmn slave idle w 129 0 3,612 28002 0.0
Streams AQ: qmn coordinator 258 50 3,612 14001 0.0
smon timer 43 2 3,605 83839 0.0
pmon timer 1,199 99 3,596 2999 0.0
SQL*Net message from client 17,019 0 31 2 0.1
SQL*Net message to client 12,762 0 0 0 0.1
class slave wait 28 0 0 0 0.0
thank you very much!Hi: just know it now: it is a large amount of 'concurrent transaction' designed in this "Volume Test" - to simulate large incoming transaction volme, so I guess wait in eq:TX - row is expected.
The fact: (1) redo logs at uat server is known to not well-tune for configurations (2) volume test slow 5%, however data amount in its test is kept the same by each time import production data, by the team. So why it slowed 5% this year?
The wait histogram is pasted below, any one interest to take a look? any ideas?
Wait Event Histogram DB/Inst: XXXX/XXXX Snaps: 5635-5636
-> Total Waits - units: K is 1000, M is 1000000, G is 1000000000
-> % of Waits - column heading: <=1s is truly <1024ms, >1s is truly >=1024ms
-> % of Waits - value: .0 indicates value was <.05%, null is truly 0
-> Ordered by Event (idle events last)
Total ----------------- % of Waits ------------------
Event Waits <1ms <2ms <4ms <8ms <16ms <32ms <=1s >1s
ADR block file read 19 26.3 5.3 10.5 57.9
ADR block file write 5 40.0 60.0
ADR file lock 6 100.0
ARCH wait for archivelog l 14 100.0
ASM file metadata operatio 30 100.0
CSS initialization 30 100.0
Disk file operations I/O 9090 97.2 1.4 .6 .4 .2 .1 .1
LGWR wait for redo copy 2447 98.5 .5 .4 .2 .2 .2 .1
Log archive I/O 35 40.0 8.6 25.7 2.9 22.9
SQL*Net break/reset to cli 34 85.3 8.8 5.9
SQL*Net more data to clien 29K 99.9 .0 .0 .0 .0 .0
buffer busy waits 1800 96.8 .7 .7 .6 .3 .4 .5
control file parallel writ 2037 90.7 5.0 2.1 .8 1.0 .3 .1
control file sequential re 7405 100.0 .0
cursor: pin S 10 10.0 90.0
db file async I/O submit 9556 99.9 .0 .0 .0
db file parallel read 1 100.0
db file parallel write 9556 62.0 32.4 1.7 .8 1.5 1.3 .1
db file scattered read 345 72.8 3.8 2.3 11.6 9.0 .6
db file sequential read 6199 97.2 .2 .3 1.6 .7 .0 .0
direct path read 7699 99.1 .4 .2 .1 .1 .0
direct path sync 8 25.0 37.5 12.5 25.0
direct path write 13K 97.8 .9 .5 .4 .3 .1 .0
enq: TX - row lock content 4480 .4 .7 1.3 3.0 6.8 12.3 75.4 .1
latch free 301 98.3 .3 .7 .7
latch: In memory undo latc 15 93.3 6.7
latch: active service list 1 100.0
latch: cache buffers chain 55 94.5 3.6 1.8
latch: cache buffers lru c 9 88.9 11.1
latch: call allocation 6 100.0
latch: checkpoint queue la 3 100.0
latch: enqueue hash chains 45 97.8 2.2
latch: messages 4 100.0
latch: object queue header 7 85.7 14.3
latch: redo allocation 113 97.3 1.8 .9
latch: row cache objects 19 89.5 5.3 5.3
latch: session allocation 5 80.0 20.0
latch: shared pool 147 90.5 1.4 2.7 1.4 .7 1.4 2.0
latch: undo global data 8 100.0
library cache: mutex X 28 89.3 3.6 3.6 3.6
log file parallel write 299K 95.6 2.6 1.0 .4 .3 .2 .0
log file sequential read 698 29.5 .1 4.6 46.8 18.9
log file single write 56 100.0
log file switch (checkpoin 4 25.0 50.0 25.0
log file switch (private s 8 12.5 37.5 50.0
log file sync 284K 93.3 3.7 1.4 .7 .5 .3 .1
os thread startup 146 100.0
row cache lock 41 85.4 9.8 2.4 2.4
DIAG idle wait 7184 100.0
SQL*Net message from clien 6379K 86.6 5.1 2.9 1.3 .7 .3 2.8 .3
SQL*Net message to client 6375K 100.0 .0 .0 .0 .0 .0 .0
Wait Event Histogram DB/Inst: XXXX/xxxx Snaps: 5635-5636
-> Total Waits - units: K is 1000, M is 1000000, G is 1000000000
-> % of Waits - column heading: <=1s is truly <1024ms, >1s is truly >=1024ms
-> % of Waits - value: .0 indicates value was <.05%, null is truly 0
-> Ordered by Event (idle events last)
Total ----------------- % of Waits ------------------
Event Waits <1ms <2ms <4ms <8ms <16ms <32ms <=1s >1s
SQL*Net more data from cli 7976 99.7 .1 .1 .0 .1
Space Manager: slave idle 4086 .1 .2 .0 .0 .3 3.2 96.1
Streams AQ: qmn coordinato 258 49.2 .8 50.0
Streams AQ: qmn slave idle 129 100.0
Streams AQ: waiting for ti 2 50.0 50.0
class slave wait 28 92.9 3.6 3.6
jobq slave wait 7270 .0 100.0
pmon timer 1199 100.0
rdbms ipc message 314K 10.3 7.3 39.7 15.4 10.6 5.3 8.2 3.3
smon timer 43 100.0 -
Library Cache Pin Wait Event (within the context of APEX)
Hello,
Firstly -
Oracle Version: 10.2.0.4.0
Apex Version: 3.0.1.00.08
Okay, my colleague (no really! This isn't one of those "Ahem ... A friend of mine has contracted something nasty +downstairs+..."-type questions) is having problems compiling a package (using TOAD incidentally, but it's the same in SQL Developer).
I've searched the forum and the web for a bit of help on what's maybe happening here and it appears to be related to a concurrency conflict with the package definition - from what I can understand it's a case of the package is in use by another session, therefore another session cannot alter it at the same time (which makes sense)
"What does this have to do with APEX?"... well, he is working on this package using the following methodology:
1. Compile the package body/spec (as necessary - body more often obviously)
2. run an apex page which uses the code in a process, which may or may not result in the error page being displayed
3. Making changes to the package body/spec
repeat steps 1-3 ad nauseum...
He is the only user directly accessing the schema (and the only user accessing the page via APEX too, although I appreciate this isn't quite the same thing).
I was wondering if, due to the architecture of APEX (the use of session pools etc), the state of a package might be being retained in some manner, thus resulting in this library cache pin wait event? If so, is there anything I can do to mitigate against this occurring?
p.s. the only difference I can see between this particular package and any other package in the schema is that this one interacts with blobs (including making references to the wwv_flow_files view) - with blobs being passed as parameters between procedures (thus potentially creating temporary blobs which may or may not being closed).
Any ideas?
p.p.s. there are also no DBMS_SCHEDULER jobs or anything that might potentially be running the code incidentally...
Edited by: Joel_C on 11-Nov-2011 11:58
We got our DBAs to run a bit of code to identify the blocking session:
select
decode(lob.kglobtyp, 0, 'NEXT OBJECT', 1, 'INDEX', 2, 'TABLE', 3, 'CLUSTER',
4, 'VIEW', 5, 'SYNONYM', 6, 'SEQUENCE',
7, 'PROCEDURE', 8, 'FUNCTION', 9, 'PACKAGE',
11, 'PACKAGE BODY', 12, 'TRIGGER',
13, 'TYPE', 14, 'TYPE BODY',
19, 'TABLE PARTITION', 20, 'INDEX PARTITION', 21, 'LOB',
22, 'LIBRARY', 23, 'DIRECTORY', 24, 'QUEUE',
28, 'JAVA SOURCE', 29, 'JAVA CLASS', 30, 'JAVA RESOURCE',
32, 'INDEXTYPE', 33, 'OPERATOR',
34, 'TABLE SUBPARTITION', 35, 'INDEX SUBPARTITION',
40, 'LOB PARTITION', 41, 'LOB SUBPARTITION',
42, 'MATERIALIZED VIEW',
43, 'DIMENSION',
44, 'CONTEXT', 46, 'RULE SET', 47, 'RESOURCE PLAN',
48, 'CONSUMER GROUP',
51, 'SUBSCRIPTION', 52, 'LOCATION',
55, 'XML SCHEMA', 56, 'JAVA DATA',
57, 'SECURITY PROFILE', 59, 'RULE',
62, 'EVALUATION CONTEXT',
'UNDEFINED') object_type,
lob.KGLNAOBJ object_name,
pn.KGLPNMOD lock_mode_held,
pn.KGLPNREQ lock_mode_requested,
ses.sid,
ses.serial#,
ses.username
FROM
x$kglpn pn,
v$session ses,
x$kglob lob,
v$session_wait vsw
WHERE
pn.KGLPNUSE = ses.saddr and
pn.KGLPNHDL = lob.KGLHDADR
and lob.kglhdadr = vsw.p1raw
and vsw.event = 'library cache pin'
order by lock_mode_held descresults as follows (I've changed some object names to protect the ignorant):
OBJECT_TYP OBJECT_NAME LOCK_MODE_HELD LOCK_MODE_REQUESTED SID SERIAL# USERNAME
PACKAGE PKG_FOOBAR 2 0 356 21694 HTMLDB_PUBLIC_U
SER
PACKAGE PKG_FOOBAR 0 3 463 22309 FOOHTMLDB_PUBLIC_USER is the apex user incidentally. The session is marked in the v$session table as "inactive", the last statement being
Begin
Dbms_session.reset_package;
End;Edited by: Joel_C on 11-Nov-2011 14:39bump
No-one?
The problem seems to have 'resolved itself' over the weekend incidentally (although I don't believe anything truly resolves itself in this manner - something must have changed). -
Problem identifying db object for "buffer busy waits" event.
10.2.0.3
AIX 64
SELECT username, a.p1text, a.p1, a.p2text, a.p2, a.p3text, a.p3, event FROM v$session a WHERE
a.status='ACTIVE'
AND a.event = 'buffer busy waits'
Query reports about 40 active sessions with this information:
file# 3746
block# 2
class# 13
select
owner,
segment_name,
segment_type
from
dba_extents
where
file_id = 3746
and
2 between block_id and block_id + blocks -1;
no rows returned
SELECT MAX(a.file#) FROM sys.file$ a
3535
This was only a temporary situation when after couple of minutes(7) wait event "buffer busy waits" dissapeared completely.
Any ideas?
Thank you,
Daniel.http://perfvision.com/papers/06_buffer_cache.ppt
Slide 80-81 points at increasing the size of the initial and next extent for File Header Block buffer busy waits
Side 85 points at high extent allocation for File Header Block buffer busy waits
http://perfvision.com/ftp/hotsos/aas.ppt
Side 55 points at extent allocation too small/too many extents being allocated for File Header Block buffer busy waits
A couple hints from the documentation:
http://download.oracle.com/docs/cd/B19306_01/server.102/b14211/instance_tune.htm
"To determine the possible causes [of buffer busy waits], first query V$SESSION to identify the value of ROW_WAIT_OBJ# when the session waits for buffer busy waits."
"To identify the object and object type contended for, query DBA_OBJECTS using the value for ROW_WAIT_OBJ# that is returned from V$SESSION."
"V$SEGMENT_STATISTICS - This is a user-friendly view of statistic values. In addition to all the columns of V$SEGSTAT, it has information about such things as the segment owner and table space name. It makes the statistics easy to understand, but it is more costly."
You may want to query DBA_TEMP_FILES for the specific FILE_ID identified by the V$SESSION. Taking a look at V$SEGMENT_STATISTICS might also be helpful.
Are you using dictionary managed tablespaces, locally managed tablespaces with manual extent size management, ASSM with manual extent size management, or ASSM with automatic extent size management?
Charles Hooper
IT Manager/Oracle DBA
K&M Machine-Fabricating, Inc. -
Enq: TX - row lock contention in TOP 5 wait event
DB version:11.1.0.7.0
I am having enq: TX - row lock contention in top 5 wait event.
AWR analyze period - 9-10(pm). During this time only one sql loader is running to insert the data. No other job are running. So there is no chance of other session blocking this session. is there any chance of row lock contention happen by same session.
SQL> SELECT INDEX_NAME,INDEX_TYPE,UNIQUENESS FROM DBA_INDEXES WHERE TABLE_NAME='DATA_DATA';
INDEX_NAME INDEX_TYPE UNIQUENES
CIDX BITMAP NONUNIQUE
VIDX BITMAP NONUNIQUE
Thanks.SQL> SELECT INDEX_NAME,INDEX_TYPE,UNIQUENESS FROM DBA_INDEXES WHERE TABLE_NAME='DATA_DATA';
INDEX_NAME INDEX_TYPE UNIQUENES
CIDX BITMAP NONUNIQUE
VIDX BITMAP NONUNIQUEYou have bitmap indexes here on a table being inserted into. Bitmap Indexes are another source of lock(and deadlock) in OLTP application. You said that the SQLloader was the unique active program but may be you are also triggering another procedure after the load. Procedure in which you might be using also automomous transactions and so on...
Check first if your table is subject to DML operation in a a multi-user concurrent accesss and in which case you have to get rid of those bitmap indexes
http://hourim.wordpress.com/2011/03/14/deadlock-%e2%80%93-part-1-bitmap-index/
Best regards
Mohamed Houri
www.hourim.wordpress.com -
Wait event "virtual circuit wait" in wait class "Network" was consuming sig
Hello,
We are facing this problem when there are 2 queries try to run at the same time.
The first query takes longer to finish so 2nd has to wait for 1st to be finished and then only 2nd starts. It seems the jam is at netowork instead of server.
I want to make sure before I start testing on network.
I get following :
Wait event "virtual circuit wait" in wait class "Network" was consuming significant database time. 98.4
Wait class "Network" was consuming significant database time.
and recommendations is stated as :
Investigate the cause for high "virtual circuit wait" waits with P1 ("circuit#") value "21" and P2 ("type") value "2".
I am checking OEM.
Thanks,
Shashi.Hello Sybrand,
Can you suggest some changes to be done to test ?
Here is my shared server config :
SQL> show parameter SHARED
NAME TYPE VALUE
hi_shared_memory_address integer 0
max_shared_servers integer
shared_memory_address integer 0
shared_pool_reserved_size big integer 135895449
shared_pool_size big integer 0
shared_server_sessions integer
shared_servers integer 1
Thanks,
Shashi. -
High Enqueue Waits in Statspack Report
Hi Everybody,
Oracle Version:Oracle9i Enterprise Edition Release 9.2.0.7.0 - 64bit Production
OS:Solaris 64 bit
Statspack Report is showing High Enqueue Waits
Here is a Snapshot.....
STATSPACK report for
DB Name DB Id Instance Inst Num Release Cluster Host
XXXXX 434917312 XXXXX 1 9.2.0.7.0 NO INgenius1
Snap Id Snap Time Sessions Curs/Sess Comment
Begin Snap: 1064 24-Sep-08 06:00:01 1,333 19.6
End Snap: 1065 24-Sep-08 07:00:01 1,344 19.7
Elapsed: 60.00 (mins)
Cache Sizes (end)
~~~~~~~~~~~~~~~~~
Buffer Cache: 1,152M Std Block Size: 8K
Shared Pool Size: 752M Log Buffer: 1,536K
Load Profile
~~~~~~~~~~~~ Per Second Per Transaction
Redo size: 27,771.53 1,196.23
Logical reads: 777.20 33.48
Block changes: 180.58 7.78
Physical reads: 33.25 1.43
Physical writes: 7.51 0.32
User calls: 76.89 3.31
Parses: 23.29 1.00
Hard parses: 0.27 0.01
Sorts: 0.42 0.02
Logons: 0.05 0.00
Executes: 88.69 3.82
Transactions: 23.22
% Blocks changed per Read: 23.23 Recursive Call %: 61.50
Rollback per transaction %: 0.00 Rows per Sort: 738.76
Instance Efficiency Percentages (Target 100%)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Buffer Nowait %: 100.00 Redo NoWait %: 100.00
Buffer Hit %: 96.90 In-memory Sort %: 99.67
Library Hit %: 99.76 Soft Parse %: 98.84
Execute to Parse %: 73.74 Latch Hit %: 99.98
Parse CPU to Parse Elapsd %: 94.38 % Non-Parse CPU: 94.45
Shared Pool Statistics Begin End
Memory Usage %: 86.56 87.54
% SQL with executions>1: 50.57 63.10
% Memory for SQL w/exec>1: 10.02 14.63
Top 5 Timed Events
~~~~~~~~~~~~~~~~~~ % Total
Event Waits Time (s) Ela Time
enqueue 19,553 57,405 98.39
db file sequential read 44,161 384 .66
CPU time 333 .57
log file parallel write 166,602 82 .14
log file sync 67,683 71 .12
Wait Events for DB: XXXXX Instance: XXXXX Snaps: 1064 - 1065
-> 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
enqueue 19,553 19,540 57,405 2936 0.2
db file sequential read 44,161 0 384 9 0.5
log file parallel write 166,602 0 82 0 2.0
log file sync 67,683 0 71 1 0.8
db file scattered read 6,676 0 54 8 0.1
db file parallel write 1,135 0 7 6 0.0
direct path read 1,117 0 3 3 0.0
SQL*Net more data to client 3,932 0 2 0 0.0
control file parallel write 1,200 0 2 1 0.0
control file sequential read 1,389 0 1 1 0.0
PX Deq: Execute Reply 112 0 0 4 0.0
direct path write 752 0 0 1 0.0
db file parallel read 9 0 0 42 0.0
Background Wait Events for DB: XXXXX Instance: XXXXX Snaps: 1064 - 10
-> ordered by wait time desc, waits desc (idle events last)
Avg Wt Wait
Eq Requests Succ Gets Failed Gets Waits Time (ms) Time (s)
TC 25 24 0 4 32.00 0
TX 84,615 84,605 0 3 8.33 0
HW 118 118 0 2 2.00 0
PS 29 25 4 2 1.00 0
Here frm Statspack Report we can see that enqueue type- TX is taking up most of the resources.......
I want to find out which sql statements are causing this high enqueue waits......
Any Help Appreciated....
Regards,
Prosenjit MukherjeeHi All,
Here is the Statspack Report..........
STATSPACK report for
DB Name DB Id Instance Inst Num Release Cluster Host
XXXXX 434917312 XXXXX 1 9.2.0.7.0 NO XXXXXxxx1
Snap Id Snap Time Sessions Curs/Sess Comment
Begin Snap: 1064 24-Sep-08 06:00:01 1,333 19.6
End Snap: 1065 24-Sep-08 07:00:01 1,344 19.7
Elapsed: 60.00 (mins)
Cache Sizes (end)
~~~~~~~~~~~~~~~~~
Buffer Cache: 1,152M Std Block Size: 8K
Shared Pool Size: 752M Log Buffer: 1,536K
Load Profile
~~~~~~~~~~~~ Per Second Per Transaction
Redo size: 27,771.53 1,196.23
Logical reads: 777.20 33.48
Block changes: 180.58 7.78
Physical reads: 33.25 1.43
Physical writes: 7.51 0.32
User calls: 76.89 3.31
Parses: 23.29 1.00
Hard parses: 0.27 0.01
Sorts: 0.42 0.02
Logons: 0.05 0.00
Executes: 88.69 3.82
Transactions: 23.22
% Blocks changed per Read: 23.23 Recursive Call %: 61.50
Rollback per transaction %: 0.00 Rows per Sort: 738.76
Instance Efficiency Percentages (Target 100%)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Buffer Nowait %: 100.00 Redo NoWait %: 100.00
Buffer Hit %: 96.90 In-memory Sort %: 99.67
Library Hit %: 99.76 Soft Parse %: 98.84
Execute to Parse %: 73.74 Latch Hit %: 99.98
Parse CPU to Parse Elapsd %: 94.38 % Non-Parse CPU: 94.45
Shared Pool Statistics Begin End
Memory Usage %: 86.56 87.54
% SQL with executions>1: 50.57 63.10
% Memory for SQL w/exec>1: 10.02 14.63
Top 5 Timed Events
~~~~~~~~~~~~~~~~~~ % Total
Event Waits Time (s) Ela Time
enqueue 19,553 57,405 98.39
db file sequential read 44,161 384 .66
CPU time 333 .57
log file parallel write 166,602 82 .14
log file sync 67,683 71 .12
Wait Events for DB: XXXXX Instance: XXXXX Snaps: 1064 - 1065
-> 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
enqueue 19,553 19,540 57,405 2936 0.2
db file sequential read 44,161 0 384 9 0.5
log file parallel write 166,602 0 82 0 2.0
log file sync 67,683 0 71 1 0.8
db file scattered read 6,676 0 54 8 0.1
db file parallel write 1,135 0 7 6 0.0
direct path read 1,117 0 3 3 0.0
SQL*Net more data to client 3,932 0 2 0 0.0
control file parallel write 1,200 0 2 1 0.0
control file sequential read 1,389 0 1 1 0.0
PX Deq: Execute Reply 112 0 0 4 0.0
direct path write 752 0 0 1 0.0
db file parallel read 9 0 0 42 0.0
process startup 6 0 0 44 0.0
SQL*Net break/reset to clien 296 0 0 1 0.0
PX Deq: Signal ACK 3 1 0 33 0.0
latch free 17 4 0 3 0.0
LGWR wait for redo copy 286 0 0 0 0.0
PX Deq: Join ACK 3 0 0 2 0.0
PX Deq: Parse Reply 4 0 0 1 0.0
buffer busy waits 12 0 0 0 0.0
PX Deq Credit: need buffer 4 0 0 0 0.0
PX Deq: Table Q Sample 1 0 0 0 0.0
SQL*Net message from client 204,628 0 4,620,111 22578 2.4
virtual circuit status 120 120 3,516 29297 0.0
PX Idle Wait 753 749 1,470 1953 0.0
SQL*Net more data from clien 20,540 0 3 0 0.2
PX Deq: Execution Msg 128 0 2 13 0.0
SQL*Net message to client 204,628 0 0 0 2.4
Background Wait Events for DB: XXXXX Instance: XXXXX Snaps: 1064 - 10
-> ordered by wait time desc, waits desc (idle events last)
Avg
Total Wait wait Waits
Event Waits Timeouts Time (s) (ms) /txn
log file parallel write 166,634 0 82 0 2.0
db file parallel write 1,134 0 8 7 0.0
control file parallel write 1,200 0 2 1 0.0
control file sequential read 1,327 0 1 1 0.0
db file scattered read 44 0 0 10 0.0
db file sequential read 25 0 0 3 0.0
direct path read 23 0 0 3 0.0
rdbms ipc reply 67 0 0 0 0.0
LGWR wait for redo copy 286 0 0 0 0.0
direct path write 23 0 0 0 0.0
buffer busy waits 2 0 0 0 0.0
rdbms ipc message 86,933 3,437 20,199 232 1.0
pmon timer 1,194 1,194 3,504 2935 0.0
smon timer 17 8 3,239 ###### 0.0
Enqueue activity for DB: XXXXX Instance: XXXXX Snaps: 1064 - 1065
-> Enqueue stats gathered prior to 9i should not be compared with 9i data
-> ordered by Wait Time desc, Waits desc
Avg Wt Wait
Eq Requests Succ Gets Failed Gets Waits Time (ms) Time (s)
TC 25 24 0 4 32.00 0
TX 84,615 84,605 0 3 8.33 0
HW 118 118 0 2 2.00 0
PS 29 25 4 2 1.00 0
End of Report (this is not the entire report,only posted part of it,getting error page when trying to post the entire report)
Regards,
Prosenjit Mukherjee -
Hi ! I have the following wait events in my top timed and I don't know who originated them:
Wait Event Wait Time Summary Avg Wait Time (ms)
I# Class Event Waits %Timeouts Total(s) Avg(ms) %DB time Avg Min Max Std Dev Cnt
* DB CPU N/A N/A 59,651.48 N/A 45.87 2
User I/O db file sequential read 4,369,213 0.0 20,831.46 4.8 16.02 4.72 4.29 5.14 0.60 2
Other enq: CF - contention 155,822 3.9 10,390.74 66.7 7.99 68.62 60.31 76.94 11.76 2
System I/O RMAN backup & recovery I/O 87,205 0.0 5,477.09 62.8 9.15 62.81 62.81 62.81 1
Cluster gc current block 2-way 2,914,457 0.0 4,811.61 1.7 3.70 1.67 1.60 1.74 0.10 2
System I/O control file sequential read 3,038,672 0.0 3,762.66 1.2 2.89 1.24 1.22 1.27 0.04 2
Concurrenc os thread startup 2,842 0.0 3,695.14 1300.2 2.84 1311.83 1143.07 1480.59 238.66 2
System I/O log file parallel write 1,341,907 0.0 2,530.17 1.9 1.95 1.88 1.88 1.89 0.01 2
Other reliable message 471,495 0.1 2,388.01 5.1 1.84 5.08 4.12 6.03 1.35 2
Concurrenc row cache lock 3,135,774 0.0 2,224.53 0.7 1.71 0.72 0.68 0.75 0.05 2
1 DB CPU N/A N/A 22,584.30 N/A 37.75
User I/O db file sequential read 2,451,215 0.0
System I/O RMAN backup & recovery I/O 87,205 0.0
Other enq: CF - contention 59,735 5.3
Cluster gc current block 2-way 1,803,542 0.0
System I/O control file sequential read 1,831,180 0.0
Concurrenc os thread startup 1,323 0.0
System I/O log file parallel write 727,883 0.0
Cluster gc cr multi block request 523,744 0.0
Concurrenc row cache lock 1,830,913 0.0
2 DB CPU N/A N/A
User I/O db file sequential read 1,917,998 0.0
Other enq: CF - contention 96,087 3.0
Cluster gc current block 2-way 1,110,915 0.0
Concurrenc os thread startup 1,519 0.0
System I/O control file sequential read 1,207,492 0.0
User I/O direct path read 404,587 0.0
Other reliable message 233,033 0.1
System I/O log file parallel write 614,024 0.0
System I/O control file parallel write 128,905 0.0
Those are the most worrying events:
enq: CF - contention
I/O control file sequential read
Concurrenc os thread startup
I have been investigating and I wonder what is wrong to get Concurrenc os thread startup. According to one blog, os thread should be always related with network issues...
The awr snapshot is from my production window day.
Rac 11.2.0.3 two nodes on Solaris Sparc 10.I have studied the ASH in the problematic period and I have found that there are some full scans:
Summary of All User Input
Format : TEXT
DB Id : 2752323407
Inst num : 1
Begin time : 08-Feb-13 09:30:00
End time : 08-Feb-13 10:20:00
Slot width : Default
Report targets : 0
Report name : ashrpt_1_0208_1020.txt
ASH Report For dbp/dbp1
DB Name DB Id Instance Inst Num Release RAC Host
dbp 2752323407 dbp1 1 11.2.0.3.0 YES host-dbp-1
CPUs SGA Size Buffer Cache Shared Pool ASH Buffer Size
16 12,651M (100%) 10,048M (79.4%) 1,921M (15.2%) 32.0M (0.3%)
Analysis Begin Time: 08-Feb-13 09:30:00
Analysis End Time: 08-Feb-13 10:20:00
Elapsed Time: 50.0 (mins)
Begin Data Source: DBA_HIST_ACTIVE_SESS_HISTORY
in AWR snapshot 5100
End Data Source: DBA_HIST_ACTIVE_SESS_HISTORY
in AWR snapshot 5101
+ V$ACTIVE_SESSION_HISTORY
Sample Count: 10,069
Average Active Sessions: 33.56
Avg. Active Session per CPU: 2.10
Report Target: None specified
Top User Events DB/Inst: dbp/dbp1 (Feb 08 09:30 to 10:20)
Avg Active
Event Event Class % Event Sessions
library cache lock Concurrency 43.73 14.68
cursor: pin S wait on X Concurrency 18.61 6.25
CPU + Wait for CPU CPU 15.77 5.29
reliable message Other 5.88 1.97
enq: KO - fast object checkpoint Application 3.48 1.17
Top Background Events DB/Inst: dbp/dbp1 (Feb 08 09:30 to 10:20)
Avg Active
Event Event Class % Activity Sessions
CPU + Wait for CPU CPU 1.25 0.42
Top Cluster Events DB/Inst: dbp/dbp1 (Feb 08 09:30 to 10:20)
Event % Event Remote I % Activity
gc current block 2-way 1.72 2 1.72
gc cr grant 2-way 1.58 N/A 1.07
Top Event P1/P2/P3 Values DB/Inst: dbp/dbp1 (Feb 08 09:30 to 10:20)
Event % Event P1 Value, P2 Value, P3 Value % Activity
Parameter 1 Parameter 2 Parameter 3
library cache lock 43.75 "29115227816","29218763456"," 1.22
handle address lock address 100*mode+namespace
"29115227816","28694732944"," 1.20
"29115227816","28812373936"," 1.17
cursor: pin S wait on X 18.61 "1497800770","3934190043136", 1.54
idn value where
"1497800770","7773890805760", 1.15
reliable message 6.07 "30432532808","30354909248"," 0.13
channel context channel handle broadcast message
enq: KO - fast object checkpoi 3.49 "1263468550","65640","1" 0.52
name|mode 2 0
db file sequential read 1.81 "1","25220","1" 0.01
file# block# blocks
Top Service/Module DB/Inst: dbp/dbp1 (Feb 08 09:30 to 10:20)
Service Module % Activity Action % Action
dbp_DVEBMGS11 CL_SQL_STATEMENT======== 86.80 383 86.80
dbp_D10_0066 CL_SQL_STATEMENT======== 6.28 383 3.34
104 2.94
dbp_D10_0064 CL_SQL_STATEMENT======== 2.40 383 2.39
SYS$BACKGROUND UNNAMED 1.51 UNNAMED 1.51
Top Client IDs DB/Inst: dbp/dbp1 (Feb 08 09:30 to 10:20)
No data exists for this section of the report.
Top SQL Command Types DB/Inst: dbp/dbp1 (Feb 08 09:30 to 10:20)
-> 'Distinct SQLIDs' is the count of the distinct number of SQLIDs
with the given SQL Command Type found over all the ASH samples
in the analysis period
Distinct Avg Active
SQL Command Type SQLIDs % Activity Sessions
SELECT 485 94.56 31.74
ALTER TABLE 220 2.89 0.97
Top Phases of Execution DB/Inst: dbp/dbp1 (Feb 08 09:30 to 10:20)
Avg Active
Phase of Execution % Activity Sessions
Parse 67.50 22.66
SQL Execution 30.46 10.22
Hard Parse 5.37 1.80
Top Remote Instances DB/Inst: dbp/dbp1 (Feb 08 09:30 to 10:20)
Wait Class % Wait Remote I % Activity
Cluster 5.22 2 3.90
N/A 1.27
Top SQL with Top Events DB/Inst: dbp/dbp1 (Feb 08 09:30 to 10:20)
Sampled #
SQL ID Planhash of Executions % Activity
Event % Event Top Row Source % RwSrc
350v06jcnd822 N/A 0 18.03
library cache lock 9.41 ** Row Source Not Available ** 9.41
SELECT "DT"."SID_0CALMONTH" AS "S____048" ,"D3"."SID_0MATERIAL" AS "S____006" ,
"DU"."SID_0UNIT" AS "S____023" ,"DT"."SID_0CALDAY" AS "S____021" ,"D2"."SID_0MET
YPE" AS "S____1342" ,"D2"."SID_0VTYPE" AS "S____504" ,"X33"."S__Z99GRMAT" AS "S_
___4443" , SUM ( "F"."QUANTITY" ) AS "Z____1299" , COUNT( * ) AS "Z____016"
N/A 0 18.03
cursor: pin S wait on X 8.62 ** Row Source Not Available ** 8.62
SELECT "DT"."SID_0CALMONTH" AS "S____048" ,"D3"."SID_0MATERIAL" AS "S____006" ,
"DU"."SID_0UNIT" AS "S____023" ,"DT"."SID_0CALDAY" AS "S____021" ,"D2"."SID_0MET
YPE" AS "S____1342" ,"D2"."SID_0VTYPE" AS "S____504" ,"X33"."S__Z99GRMAT" AS "S_
___4443" , SUM ( "F"."QUANTITY" ) AS "Z____1299" , COUNT( * ) AS "Z____016"
48unmtd983uz6 N/A 0 16.75
library cache lock 12.87 ** Row Source Not Available ** 12.87
SELECT "DT"."SID_0CALDAY" AS "S____021" ,"DT"."SID_0CALMONTH" AS "S____048" ,"D
3"."SID_0MATERIAL" AS "S____006" ,"DU"."SID_0UNIT" AS "S____023" ,"D2"."SID_0MET
YPE" AS "S____1342" ,"D2"."SID_0VTYPE" AS "S____504" , SUM ( "F"."QUANTITY" )
AS "Z____1299" , COUNT( * ) AS "Z____016" FROM "/BIC/FZ99IC114" "F" JOIN "/BIC
N/A 0 16.75
cursor: pin S wait on X 3.88 ** Row Source Not Available ** 3.88
SELECT "DT"."SID_0CALDAY" AS "S____021" ,"DT"."SID_0CALMONTH" AS "S____048" ,"D
3"."SID_0MATERIAL" AS "S____006" ,"DU"."SID_0UNIT" AS "S____023" ,"D2"."SID_0MET
YPE" AS "S____1342" ,"D2"."SID_0VTYPE" AS "S____504" , SUM ( "F"."QUANTITY" )
AS "Z____1299" , COUNT( * ) AS "Z____016" FROM "/BIC/FZ99IC114" "F" JOIN "/BIC
350v06jcnd822 2426825131 0 15.49
library cache lock 9.74 ** Row Source Not Available ** 9.74
SELECT "DT"."SID_0CALMONTH" AS "S____048" ,"D3"."SID_0MATERIAL" AS "S____006" ,
"DU"."SID_0UNIT" AS "S____023" ,"DT"."SID_0CALDAY" AS "S____021" ,"D2"."SID_0MET
YPE" AS "S____1342" ,"D2"."SID_0VTYPE" AS "S____504" ,"X33"."S__Z99GRMAT" AS "S_
___4443" , SUM ( "F"."QUANTITY" ) AS "Z____1299" , COUNT( * ) AS "Z____016"
cursor: pin S wait on X 4.14 ** Row Source Not Available ** 4.14
CPU + Wait for CPU 1.61 SELECT STATEMENT 1.58
48unmtd983uz6 3511339786 0 14.98
library cache lock 11.50 ** Row Source Not Available ** 11.50
SELECT "DT"."SID_0CALDAY" AS "S____021" ,"DT"."SID_0CALMONTH" AS "S____048" ,"D
3"."SID_0MATERIAL" AS "S____006" ,"DU"."SID_0UNIT" AS "S____023" ,"D2"."SID_0MET
YPE" AS "S____1342" ,"D2"."SID_0VTYPE" AS "S____504" , SUM ( "F"."QUANTITY" )
AS "Z____1299" , COUNT( * ) AS "Z____016" FROM "/BIC/FZ99IC114" "F" JOIN "/BIC
cursor: pin S wait on X 1.97 ** Row Source Not Available ** 1.97
CPU + Wait for CPU 1.51 SELECT STATEMENT 1.42
07tcvyb6frtkx 2929764020 1 1.87
gc cr grant 2-way 0.80 TABLE ACCESS - BY USER ROWID 0.75
SELECT "D3"."SID_0SHIP_TO" AS "SID" FROM "/BIC/FZ99IC035" "F" JOIN "/BIC/DZ99IC
0352" "D2" ON "F" . "KEY_Z99IC0352" = "D2" . "DIMID" JOIN "/BI0/XMATERIAL" "X9"
ON "D2" . "SID_0MATERIAL" = "X9" . "SID" JOIN "/BIC/DZ99IC0355" "D5" ON "F" .
"KEY_Z99IC0355" = "D5" . "DIMID" JOIN "/BIC/DZ99IC0353" "D3" ON "F" . "KEY_Z99
Top SQL with Top Events DB/Inst: dbp/dbp1 (Feb 08 09:30 to 10:20)
Sampled #
SQL ID Planhash of Executions % Activity
Event % Event Top Row Source % RwSrc
Top SQL with Top Row Sources DB/Inst: dbp/dbp1 (Feb 08 09:30 to 10:20)
Sampled #
SQL ID PlanHash of Executions % Activity
Row Source % RwSrc Top Event % Event
350v06jcnd822 N/A 0 18.03
** Row Source Not Available ** 18.03 library cache lock 9.41
SELECT "DT"."SID_0CALMONTH" AS "S____048" ,"D3"."SID_0MATERIAL" AS "S____006" ,
"DU"."SID_0UNIT" AS "S____023" ,"DT"."SID_0CALDAY" AS "S____021" ,"D2"."SID_0MET
YPE" AS "S____1342" ,"D2"."SID_0VTYPE" AS "S____504" ,"X33"."S__Z99GRMAT" AS "S_
___4443" , SUM ( "F"."QUANTITY" ) AS "Z____1299" , COUNT( * ) AS "Z____016"
48unmtd983uz6 N/A 0 16.75
** Row Source Not Available ** 16.75 library cache lock 12.87
SELECT "DT"."SID_0CALDAY" AS "S____021" ,"DT"."SID_0CALMONTH" AS "S____048" ,"D
3"."SID_0MATERIAL" AS "S____006" ,"DU"."SID_0UNIT" AS "S____023" ,"D2"."SID_0MET
YPE" AS "S____1342" ,"D2"."SID_0VTYPE" AS "S____504" , SUM ( "F"."QUANTITY" )
AS "Z____1299" , COUNT( * ) AS "Z____016" FROM "/BIC/FZ99IC114" "F" JOIN "/BIC
350v06jcnd822 2426825131 0 15.49
** Row Source Not Available ** 13.91 library cache lock 9.74
SELECT "DT"."SID_0CALMONTH" AS "S____048" ,"D3"."SID_0MATERIAL" AS "S____006" ,
"DU"."SID_0UNIT" AS "S____023" ,"DT"."SID_0CALDAY" AS "S____021" ,"D2"."SID_0MET
YPE" AS "S____1342" ,"D2"."SID_0VTYPE" AS "S____504" ,"X33"."S__Z99GRMAT" AS "S_
___4443" , SUM ( "F"."QUANTITY" ) AS "Z____1299" , COUNT( * ) AS "Z____016"
SELECT STATEMENT 1.58 CPU + Wait for CPU 1.58
48unmtd983uz6 3511339786 0 14.98
** Row Source Not Available ** 13.56 library cache lock 11.50
SELECT "DT"."SID_0CALDAY" AS "S____021" ,"DT"."SID_0CALMONTH" AS "S____048" ,"D
3"."SID_0MATERIAL" AS "S____006" ,"DU"."SID_0UNIT" AS "S____023" ,"D2"."SID_0MET
YPE" AS "S____1342" ,"D2"."SID_0VTYPE" AS "S____504" , SUM ( "F"."QUANTITY" )
AS "Z____1299" , COUNT( * ) AS "Z____016" FROM "/BIC/FZ99IC114" "F" JOIN "/BIC
SELECT STATEMENT 1.42 CPU + Wait for CPU 1.42
07tcvyb6frtkx 2929764020 1 1.87
TABLE ACCESS - BY USER ROWID 1.59 gc cr grant 2-way 0.75
SELECT "D3"."SID_0SHIP_TO" AS "SID" FROM "/BIC/FZ99IC035" "F" JOIN "/BIC/DZ99IC
0352" "D2" ON "F" . "KEY_Z99IC0352" = "D2" . "DIMID" JOIN "/BI0/XMATERIAL" "X9"
ON "D2" . "SID_0MATERIAL" = "X9" . "SID" JOIN "/BIC/DZ99IC0355" "D5" ON "F" .
"KEY_Z99IC0355" = "D5" . "DIMID" JOIN "/BIC/DZ99IC0353" "D3" ON "F" . "KEY_Z99
Top SQL using literals DB/Inst: dbp/dbp1 (Feb 08 09:30 to 10:20)
-> FORCE_MATCHING_SIGNATURE is used to identify SQL statements that are
identical except for their use of literals.
-> Please refer to the Oracle Database Reference to understand how
the FORCE_MATCHING_SIGNATURE is derived.
# of Sampled
FORCE_MATCHING_SIGNATURE % Activity SQL Versions
Example SQL 1
Example SQL 2
1021017294885722791 2.89 218
0htvt0stu1vtq
SELECT COUNT(*) FROM "/BIC/FZ99IC003" WHERE "KEY_Z99IC003P" = :A0
0htvt0stu1vtq
Top Parsing Module/Action DB/Inst: dbp/dbp1 (Feb 08 09:30 to 10:20)
Module Action % Activ Event
CL_SQL_STATEMENT============== 383 67.25 library
383 cursor:
383 CPU + Wa
Top Sessions running PQs DB/Inst: dbp/dbp1 (Feb 08 09:30 to 10:20)
-> This section aggregates all the work done by the PQ slaves into
the session issuing the parallel query.
Sid,Srl# (Inst) % Activity SQL ID Event % Event
User Program
1506, 19(1) 33.57 350v06jcnd822 library cache lock 19.15
UserID:
SELECT "DT"."SID_0CALMONTH" AS "S____048" ,"D3"."SID_0MATERIAL" AS "S____006" ,
"DU"."SID_0UNIT" AS "S____023" ,"DT"."SID_0CALDAY" AS "S____021" ,"D2"."SID_0MET
YPE" AS "S____1342" ,"D2"."SID_0VTYPE" AS "S____504" ,"X33"."S__Z99GRMAT" AS "S_
___4443" , SUM ( "F"."QUANTITY" ) AS "Z____1299" , COUNT( * ) AS "Z____016"
cursor: pin S wait on X 12.76
SELECT "DT"."SID_0CALMONTH" AS "S____048" ,"D3"."SID_0MATERIAL" AS "S____006" ,
"DU"."SID_0UNIT" AS "S____023" ,"DT"."SID_0CALDAY" AS "S____021" ,"D2"."SID_0MET
YPE" AS "S____1342" ,"D2"."SID_0VTYPE" AS "S____504" ,"X33"."S__Z99GRMAT" AS "S_
___4443" , SUM ( "F"."QUANTITY" ) AS "Z____1299" , COUNT( * ) AS "Z____016"
CPU + Wait for CPU 1.61
SELECT "DT"."SID_0CALMONTH" AS "S____048" ,"D3"."SID_0MATERIAL" AS "S____006" ,
"DU"."SID_0UNIT" AS "S____023" ,"DT"."SID_0CALDAY" AS "S____021" ,"D2"."SID_0MET
YPE" AS "S____1342" ,"D2"."SID_0VTYPE" AS "S____504" ,"X33"."S__Z99GRMAT" AS "S_
___4443" , SUM ( "F"."QUANTITY" ) AS "Z____1299" , COUNT( * ) AS "Z____016"
2255, 1067(1) 31.78 48unmtd983uz6 library cache lock 24.37
UserID:
SELECT "DT"."SID_0CALDAY" AS "S____021" ,"DT"."SID_0CALMONTH" AS "S____048" ,"D
3"."SID_0MATERIAL" AS "S____006" ,"DU"."SID_0UNIT" AS "S____023" ,"D2"."SID_0MET
YPE" AS "S____1342" ,"D2"."SID_0VTYPE" AS "S____504" , SUM ( "F"."QUANTITY" )
AS "Z____1299" , COUNT( * ) AS "Z____016" FROM "/BIC/FZ99IC114" "F" JOIN "/BIC
cursor: pin S wait on X 5.85
SELECT "DT"."SID_0CALDAY" AS "S____021" ,"DT"."SID_0CALMONTH" AS "S____048" ,"D
3"."SID_0MATERIAL" AS "S____006" ,"DU"."SID_0UNIT" AS "S____023" ,"D2"."SID_0MET
YPE" AS "S____1342" ,"D2"."SID_0VTYPE" AS "S____504" , SUM ( "F"."QUANTITY" )
AS "Z____1299" , COUNT( * ) AS "Z____016" FROM "/BIC/FZ99IC114" "F" JOIN "/BIC
CPU + Wait for CPU 1.51
SELECT "DT"."SID_0CALDAY" AS "S____021" ,"DT"."SID_0CALMONTH" AS "S____048" ,"D
3"."SID_0MATERIAL" AS "S____006" ,"DU"."SID_0UNIT" AS "S____023" ,"D2"."SID_0MET
YPE" AS "S____1342" ,"D2"."SID_0VTYPE" AS "S____504" , SUM ( "F"."QUANTITY" )
AS "Z____1299" , COUNT( * ) AS "Z____016" FROM "/BIC/FZ99IC114" "F" JOIN "/BIC
Top DB Objects DB/Inst: dbp/dbp1 (Feb 08 09:30 to 10:20)
-> With respect to Application, Cluster, User I/O and buffer busy waits only.
Object ID % Activity Event % Event
Object Name (Type) Tablespace
13661539 2.45 gc buffer busy acquire 0.87
SAPSR3./BIC/EZ99IC013 (TABLE) PSAPSR3SSD
Top DB Files DB/Inst: dbp/dbp1 (Feb 08 09:30 to 10:20)
-> With respect to Cluster and User I/O events only.
File ID % Activity Event % Event
File Name Tablespace
53 3.60 gc current block 2-way 0.98
+dbp_DATA/dbp_2/datafile/psapsr3ssd.315.805562113 PSAPSR3SSD
Top Latches DB/Inst: dbp/dbp1 (Feb 08 09:30 to 10:20)
No data exists for this section of the report.
Activity Over Time DB/Inst: dbp/dbp1 (Feb 08 09:30 to 10:20)
-> Analysis period is divided into smaller time slots
-> Top 3 events are reported in each of those slots
-> 'Slot Count' shows the number of ASH samples in that slot
-> 'Event Count' shows the number of ASH samples waiting for
that event in that slot
-> '% Event' is 'Event Count' over all ASH samples in the analysis period
Slot Event
Slot Time (Duration) Count Event Count % Event
09:30:00 (5.0 min) 260 gc buffer busy acquire 43 0.43
reliable message 34 0.34
CPU + Wait for CPU 29 0.29
09:35:00 (5.0 min) 303 CPU + Wait for CPU 76 0.75
db file sequential read 40 0.40
gc buffer busy acquire 39 0.39
09:40:00 (5.0 min) 366 CPU + Wait for CPU 209 2.08
db file sequential read 26 0.26
gc current block 2-way 22 0.22
09:45:00 (5.0 min) 511 CPU + Wait for CPU 249 2.47
cursor: pin S wait on X 93 0.92
reliable message 45 0.45
09:50:00 (5.0 min) 2,245 cursor: pin S wait on X 1,442 14.32
library cache lock 407 4.04
reliable message 112 1.11
09:55:00 (5.0 min) 2,037 library cache lock 1,378 13.69
cursor: pin S wait on X 297 2.95
CPU + Wait for CPU 125 1.24
10:00:00 (5.0 min) 1,823 library cache lock 1,371 13.62
CPU + Wait for CPU 263 2.61
reliable message 72 0.72
10:05:00 (5.0 min) 1,273 library cache lock 866 8.60
CPU + Wait for CPU 155 1.54
reliable message 96 0.95
10:10:00 (5.0 min) 798 library cache lock 350 3.48
CPU + Wait for CPU 287 2.85
reliable message 54 0.54
10:15:00 (5.0 min) 436 CPU + Wait for CPU 200 1.99
reliable message 61 0.61
enq: KO - fast object checkpoi 42 0.42
-------------------------------------------------------------Problems are always on instance 1.
The queries are different each day, the top sql with performance problem changes the sql_id and I cant attack them or apply a sql profile or tune them because they only execute during a period.
Any idea?
:( -
Hello SAP Community,
I start by mentioning a few details about the system I'll be talking about in this subject:
- SAP NetWeaver 7.0
- Oracle Database 10.2g
I was reading the following Note: "Note 618868 - FAQ: Oracle performance", in order to try to understand what's causing the oracle database to have slow performance.
While reading section 3 "How can I determine whether the general database performance can be optimized?" I found out that the ratio of "Busy wait time to CPU time" is away above the recommended 60:40 value. I'm getting a 94:6 ratio. This value was calculated using the query:
SELECT
ROUND((STM1.VALUE - STM2.VALUE) / 1000000) "BUSY WAIT TIME (S)",
ROUND(STM2.VALUE / 1000000) "CPU TIME (S)",
ROUND((STM1.VALUE - STM2.VALUE) / STM1.VALUE * 100) || ' : ' ||
ROUND(STM2.VALUE / STM1.VALUE * 100) RATIO
FROM V$SYS_TIME_MODEL STM1, V$SYS_TIME_MODEL STM2
WHERE STM1.STAT_NAME = 'DB time' AND STM2.STAT_NAME = 'DB CPU';
With such high values, SAP recommends to improve system performance doing some "wait event tuning".
Can someone give me some directions about this subject? Some guides specific to this subject would be nice. Any further information about my system you may require, please ask me.
Thanks in advance.
Best regards,
Daniel GarridoHello again,
Before I did any changes to the Oracle's parameters I checked the Note 619188 - FAQ: Oracle wait events, to understand what could be causing such high event wait time.
With the query:
SELECT EVENT, TOTAL_WAITS, TIME_WAITED, AVG_MS,
ROUND(RATIO_TO_REPORT(TIME_WAITED) OVER () * 100) PERCENT
FROM (SELECT SUBSTR(EVENT, 1, 30) EVENT, TOTAL_WAITS, TIME_WAITED,
ROUND(TIME_WAITED_MICRO / TOTAL_WAITS / 1000, 2) AVG_MS
FROM V$SYSTEM_EVENT
WHERE WAIT_CLASS NOT IN ('Idle', 'System I/O')
UNION
SELECT 'CPU' EVENT, NULL, VALUE, NULL
FROM V$SYSSTAT
WHERE STATISTIC# = 12
ORDER BY 3 DESC)
WHERE ROWNUM <=10;
I got the non-idle events that took more time in my system and the result was:
Result of the SELECT statement
EVENT
TOTAL_WAITS
TIME_WAITED
AVG_MS
PERCENT
log file switch (archiving nee
578.686
57.850.863
999.69
80
buffer busy waits
712.163
6.420.932
90.16
9
CPU
0
2.791.238
4
db file sequential read
4.005.546
1.746.442
4.36
2
log file sync
10.176.490
1.577.177
1.55
2
enq: TX - row lock contention
854.451
642.955
7.52
1
db file scattered read
1.055.533
621.332
5.89
1
enq: CF - contention
210.085
246.910
11.75
0
read by other session
561.558
119.910
2.14
0
log file switch completion
10.777
85.843
79.65
0
So most of the TIME_WAITED for wait events was because of the "log file switch (archiving needed)", after reading what could cause such wait event, I understood this was related with a problem I previously had in the server, where the archiving folder was with no space left. (Meanwhile the backup of the archives is being done and so the folder is being cleaned on a daily basis).
Thank you all for your help!
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