Re: v$rowcache outstanding_alerts

Somewhere I have some notes about this that I wrote a couple of years ago when I came across a system with an idgen2$.

It's an unusual object because it's generated dynamically in the executable when database creation takes place, and its presence is recorded in table idgens$. I don't recall whether the table holds one row per idgenX$ or whether it just holds the highest value for X.

Changes of 10,000 per minute is not necessarily a big issue - if you check the "increment by" value for the sequence it's 50, so the rate of calls is one fiftieth of the rate of change.

I have a VERY VAGUE memory that the sequence was something to do with abstract data types (i.e. objects) and generated object type IDs.

Regards

Jonathan Lewis
http://jonathanlewis.wordpress.com/all-postings

Author: Oracle Core (Apress 2011)
http://www.apress.com/9781430239543

• Original Message ----- From: "Walker, Jed S" <Jed_Walker_at_cable.comcast.com> To: <oracle-l_at_freelists.org> Sent: Thursday, November 15, 2012 7:44 PM Subject: RE: v$rowcache outstanding_alerts

| Thanks Joe, I'm not sure why I didn't find that one.
|
| So, it would appear that I'll have to leave it and accept that
dc_sequences will have a high miss ratio. I checked another system (non-RAC) and the sequence has never been used.
|
| " it is an internal sequence created at database creation that we use
internally for various things." It'd sure be nice to have more info than that.
|
| -----Original Message-----
| From: Sweetser, Joe [mailto:JSweetser_at_icat.com]
| Sent: Thursday, November 15, 2012 12:35 PM
| To: Walker, Jed S; oracle-l_at_freelists.org
| Subject: RE: v$rowcache outstanding_alerts
|
| This has some info on it:

http://asktom.oracle.com/pls/apex/f?p=100:11:0::::P11_QUESTION_ID:3303121200346990096
|
| hth,
| -joe
|
| -----Original Message-----
| From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Walker, Jed S
| Sent: Thursday, November 15, 2012 12:31 PM
| To: oracle-l_at_freelists.org
| Subject: RE: v$rowcache outstanding_alerts
|
| Thanks Tanel.
| I've modified the application sequences and noticed the overall miss
ratio not improving. I discovered this sequence:
|
| SYS.IDGEN1$
|
| It has a cache_size of 1000; however, the last_number is updating by
10,000 values per minute. I also posted this on MOC, but was hoping someone here might know about this sequence -
|

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