Hi Mark ,
Thanks for revert !
EVENT COUNT(*) PERCENT
----------------------------------- ---------- ----------
enq: TX - allocate ITL entry 372570 46% ==> update
statement updates status column ,avg.row len:138 and blocks :419217 table
size:3.2GB
302698 37%==> update
statement updates status and one more column ,avg.row len :207 table size
:92 GB
1.not sure how insertion happens , but it updates status column in both
tables
2.Block size is 8K , i am not sure about rows are often multi-block rows
or not
3.Rows are not migrated rows
Update statement does not has any older history of execution , from last 2
month of AWR data , we could see that only got executed at 3 -APR , below
is execution with 30 mins of snap.
Q1 Q2 Q3 Q3
9672 2585 2259 2602
803 1112 1070 1111
4245 3839 3316 3840
1707 1280 1358 1279
2827 1659 1968 1659
874 1592 1146 1590
1715 2417 2479 2419
11487 8151 18507 8145
1610 1676 1757 1675
386 693 575 694
1772 690 785 691
7596 5227 5559 5227
258 474 283 475
784 964 511 970
1810 2076 1315 2073
3930 2922 3154 2918
3235 3172 2628 3171
3971 3350 3261 3350
2735 2749 1707 2750
3094 4233 4409 4235
5391 5839 6012 5842
7309 6428 6899 6417
2335 2017 1839 2016
10455 9438 10096 9438
4702 2731 2417 2734
3316 9801 10653 9804
*188891* *187068* *189944* *187061*
1707 1027 1066 1031
11642 4481 8448 4490
8852 9287 4333 9318
TOTAL 309111 288978 299754 289025
Regards,
Krishna
On Fri, 5 Apr 2024 at 03:31, Mark W. Farnham <mwf@xxxxxxxx> wrote:
So you have a particular table.
Let’s talk about that table.
How many rows are there per block for that table? (min, max, average).
How many insert, update, and delete operations can reasonably be
simultaneously in play for that table?
I’m restraining myself from asking about indexes because you wrote that
you’re sure that is not it.
Are rows inserted into this table born “full length” or is a skeleton key
insert made with lots of null columns which are then updated to actual
values?
Are the rows often multi-block rows?
Are there many migrated rows?
After a row is inserted and perhaps updated a few times very soon after
the insert, does it tend to become quiet and rarely if ever be updated
again?
Your answers to these questions will tend to reduce the possible
improvement suggestions from hundreds to a dozen or fewer.
Good luck,
mwf
*From:* oracle-l-bounce@xxxxxxxxxxxxx [mailto:
oracle-l-bounce@xxxxxxxxxxxxx] *On Behalf Of *Krishnaprasad Yadav
*Sent:* Thursday, April 04, 2024 1:02 PM
*To:* Pierre Labrousse
*Cc:* Oracle L
*Subject:* Re: ITL waits
Adding some more info , querys lio is around 15 to 17 only
On Thu, 4 Apr, 2024, 22:31 Krishnaprasad Yadav, <chrishna0007@xxxxxxxxx>
wrote:
Dear Pierre,
Thanks for your reply
I have seen top object is table from reports , so 100%sure on it
I know inittrans would help but what i feel that its might be cascaded one
(suspecting) because as i mentioned
Concurrency is low , table size is low
Not sure about connection strom which i need to work on
Regards,
Krish
On Thu, 4 Apr, 2024, 21:43 Pierre Labrousse, <Pierre.Labrousse@xxxxxxxxxx>
wrote:
Hello Krishna,
Are you sure that waits are on table segment and not on index segment ?
Generally this waits appears more on indexes than tables.
Effectively, INITRANS should be raised (by default it's 1 for table and
2 for index), but it will be taken into account only for new blocks (unless
you move table or rebuild index). You could also raise PCTFREE to have less
rows into the same block or create a new tablespace with a data block size
smaller to minimize number of rows into the same block and move your
tables/index into this tablespace.
Partitioning would be a good solution but it is "just" extra cost 😉
Best regards.
Pierre
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*Consultant DBA ORACLE (OCM 10g/11g/12c)*
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------------------------------
*De :* oracle-l-bounce@xxxxxxxxxxxxx <oracle-l-bounce@xxxxxxxxxxxxx> de
la part de Krishnaprasad Yadav <chrishna0007@xxxxxxxxx>
*Envoyé :* jeudi 4 avril 2024 17:05
*À :* Oracle L <oracle-l@xxxxxxxxxxxxx>
*Objet :* ITL waits
Dear Gurus ,
i have made observation of ITL waits in DB , and it lasted more than 4+hrs
i see that certain new DML was introduced newly in database , and same
time these ITL wait events triggered .
I validated top object i see 3 tables were seen as DML are using these
tables , i saw concurrency it was around 3k to 10K in 30 mins of snap .
Also table is non partitioned and it was only 3GB in size .
total execution in DAY was around 400K for all 3 DML statements , seeing
these bit surprise that how with such low concurrency its landed in issue
Also able extent management is AUTO .
i know increasing INITTRANS will help them (probably ?) but i am
suspecting its coming something out of DB , i validated OS watcher details
, i see some potential bottleneck but those stats which i suspect as
bottleneck are seen in good time as well , i validate CPU utilization
which was high during start of issue but after 10 mins it got down to 60%
but spike remain in DB , validate IO busyness trend is similar to CPU .
It will be helpful if you can share any of experience from which i can
relate and take ahead my case .
Regards,
Krishna
