constant monitoring and enqueues?

Hi

I'm looking to write something (mainly to try and teach myself Java - urk!) that will monitor the performance of various oracle counters (cache hits etc) and graph them.

My question is this: if I'm taking a sample every couple of seconds say, am I reasonably safe if I stay to selecting from v$ views for example? I'm thinking of repeatedly querying things and am worried for performance reasons here...

My basic idea-template for this is from looking at the neat graphs in the demo of Quest Software's Instance Monitor which from the quick look I had, appears to garner rather a lot of information, quickly and repeatedly. I notice in this months Oracle mag that there's an ad for SQLab Vision which claims to collect SQL statements non-intrusively, with no overhead to Oracle. How?

Is it perhaps tunneling in some other way and getting at the performance information in some other less-intrusive manner? Or is my thinking on this all wrong?

While I'm on the subject, if I want to decipher exactly where my enqueues are queueing, I know which tables to read. The problem is that I need to read them at enqueue time - is there an event I can set that will grab these when they occur or do I have to rely on hoping that I'm querying these tables just in time? A list of events is where btw?

Thanks in advance for any ideas/avenues to explore.

Andrew Received on Mon Jan 08 2001 - 08:30:44 CST