RE: v$rowcache outstanding_alerts

From: Sweetser, Joe <>
Date: Thu, 15 Nov 2012 20:29:32 +0000
Message-ID: <>

Also found this:

The sequence IDGEN1$ is a sequence in SYS dealing with Transportable tablespace, therefore you should under no circumstances touch it.


The thread is around someone using idgen1$.nextval. (no comment) And I have no idea if the information above is accurate but maybe it's something to look at if you use TTs.


-----Original Message-----

From: [] On Behalf Of Walker, Jed S Sent: Thursday, November 15, 2012 12:45 PM To:
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 [] Sent: Thursday, November 15, 2012 12:35 PM To: Walker, Jed S; Subject: RE: v$rowcache outstanding_alerts

This has some info on it:


-----Original Message-----

From: [] On Behalf Of Walker, Jed S Sent: Thursday, November 15, 2012 12:31 PM To:
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 -

  1. What is it for?
  2. How to find if there is an issue causing it to update so rapidly
  3. Can one safely increase the cache size on it?



From: [] On Behalf Of Tanel Poder Sent: Wednesday, November 14, 2012 6:17 PM To: Walker, Jed S
Subject: Re: v$rowcache outstanding_alerts

It's used for server alerting infrastructure (metrics thresholds, tablespace space etc)

DESC dba_outstanding_alerts
DESC dbms_server_alert
SELECT * FROM v$alert_types;

I wouldn't worry about the miss ratio as this may be just due to the alerts being read infrequently (after they've been aged out from cache) and this number has accumulated over a long time...


Tanel Poder
Blog -
App -

On Thu, Nov 15, 2012 at 12:46 AM, Walker, Jed S <<>> wrote: I am looking in the v$rowcache table and found something that I haven't been able to find out about.


-------------------------------- ---------- ------------- ---------- ---------- ---------- ...
outstanding_alerts 4 739 59443 56431 94.93

Does anyone know what this particular item is, and why it would have such a high miss percentage?





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-- Received on Thu Nov 15 2012 - 21:29:32 CET

Original text of this message