What AQ$_PLSQL_NTFNnnnn scheduler jobs are used for?

I don't use Advanced Queueing at all, but amount of AQ$_PLSQL_NTFNnnnn scheduler jobs grows continuously.

Currently there are 8 such jobs. And because of them - I need to refresh maximum simultaneous jobs running count.

About 2 months ago it was ok with limit of 10, currently I have limit 15 and because of 8 "unnecessary" (at least for me) that jobs - I need to increase it to even 20 or 25 :-S

So, what are they used for? Can I just drop/disable them?

UPD: I've increased number of simultaneous jobs to 25 and in开发者_运维技巧 this night the amount of AQ... jobs rose up to 25 :-S Is it a joke?!

It sounds to me like something is using AQ somewhere in your database.

I googled around a bit, and there is some possibly useful information here - http://www.ora600.be/node/5547 - mostly the hidden parameter _srvntfn_max_concurrent_jobs that apparently limits the total number of jobs running for notifications.

Information seems to be hard to come by, but apparently notifications go into the table sys.alert_qt, so you could try having a look in there to see what appears.

You could also have a look in the ALL_QUEUES and other ALL_QUEUE* tables to see if there are any queues on your database you are not aware of.

I am assuming you are using Oracle 11gR1 or 11gR2?

When using a PL/SQL Callback function for processing the AQ queue, we have seen these jobs being generated. You can check this table to find any registered subscriptions:

  select * from   dba_subscr_registrations;

More about AQ PL/SQL Callback