Re: Tablespace Usage and Performance

From: Robert Klemme <>
Date: Wed, 12 Nov 2008 21:38:16 +0100
Message-ID: <>

On 12.11.2008 19:06, joel garry wrote:
> On Nov 12, 9:02 am, Mark D Powell <> wrote:

>> What this example proves is that too many of the programmers Oracle >> hires to write its applications do not understand how Oracle works.

Hmmm... (see below)

> While it may be true, I think "proof" isn't there. The real problem
> is jumping to unwarranted conclusions, like "EM complains my TS is 85%
> full, I see some vaguely defined slowdown, therefore there is a causal
> relationship." We probably all agree that more research would need to
> be done to make such a causation claim, and probably all enjoy the
> nitpicking involved :-)


> In this case, however, I kind of see how the product managers of EM
> would have to come up with some arbitrary default figure, the lameness
> comes in describing the use to users. Perhaps a case of good
> intentions gone to hell, oversimplification changing interpretation to
> wrong conclusions. In that context, Daniel's answer becomes quite
> correct, as does your initial answer.

IIRC the 85% is the default warning threshold for EM which I believe is intended rather to support resource planning than as performance indicator or warning. If you limit TS size you want to be aware well ahead of time that you need to add datafiles in order to not disrupt service... So, IMHO there is good reason to choose this figure.

> Of course, implicit in the OP is a desire to show the someone who made
> the statement the error of his ways.

The tricky thing about that statement is that it is an assumption about causal relationship disguised in a purely descriptive statement. I chose to address the descriptive content mainly to provide a different perspective while most others addressed the hidden assumption - for good reasons.


        robert Received on Wed Nov 12 2008 - 14:38:16 CST

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