RE: enq HW - contention waits

Ravi,  

We have run very intense loads on a large DW and I don't remember running into this problem (same version and OS). Not having seen this event, If I were to go out on a limb, I would say that that seems to suggest that there are too many extents being allocated to accommodate growth. What is the next extent size for the table?  

-Krish
 

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Ravi Gaur
Sent: Friday, April 18, 2008 2:34 PM
To: oracle-l
Subject: enq HW - contention waits  

Greetings,

We have a production database running on RAC (4-node) (10.2.0.3 on Solaris 10) and I'm noticing a lot of waits on "enq: HW - contention". Doing a bit of researching tells me that it is related to HWM extensions (concurrent inserts). We have no control on the application so I wonder what could be done from the database end to tune this up (if anything). Here's what I see from the AWR during the time it showed up --

Top 5 Timed Events

Event

Waits

Time(s)

Avg Wait(ms)

% Total Call Time

Wait Class

CPU time  

7,148  

43.5  

enq: HW - contention

67,034

5,263

79

32.0

Configuration

SQL*Net break/reset to client

61,006

1,504

25

9.2

Application

db file sequential read

152,431

885

6

5.4

User I/O

gc cr block busy

34,315

490

14

3.0

Cluster

Any help is deeply appreciated!!

TIA,
- Ravi Gaur

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http://www.freelists.org/webpage/oracle-l Received on Fri Apr 18 2008 - 17:57:06 CDT