RE: autoextend

  • From: "Powell, Mark D" <mark.powell@xxxxxxx>
  • To: "oracle-l" <oracle-l@xxxxxxxxxxxxx>
  • Date: Mon, 25 Sep 2006 12:41:20 -0400

Using unlimited file size is a bad idea because as soon as you remove
the maxsize parameter value some developer will manage to move an
infinite insert into production (that is, an infinite loop containing an
insert statement).  Cleaning up the mess from a job filling a disk is a
lot worse than having to alter the maximum file size larger.

If you are actively monitoring your space usage you should have plenty
of notice that you need to increase the max size. 

-- Mark D Powell --
Phone (313) 592-5148

-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of
Sent: Monday, September 25, 2006 11:13 AM
To: Dennis Williams; oracle-l
Subject: Re: autoextend


Regarding your point #2 (MAXSIZE). We are debating setting it to
The argument for not setting it to unlimited is that we currently have
the MAXSIZE set to about 3 times the current size of the file. And we
only need to expand this file once in the last several years. And I
think there is a general sence of not giving Oracle too much access.

I am however leaning towards setting it to unlimited precisely to avoid
that "gotcha". This is a very high profile application and we can't
afford to have it running out of space. Plus we will have OEM monitoring
set up to notify us when the tablespace is close to being filled and
therefore we should know when it is going to be expanded.
with the monitoring turned on, I can't see a scenario when unlimited
maxsize will cause problems. Is there anything that I 'm missing here?

thank you

Gene Gurevich
Oracle Engineering


             "Dennis Williams"


             09/21/2006 11:04

                                       Re: autoextend








Nope, it will only extend when it needs. Look at RESIZE to immediately
change the size.

Also be sure to mention your platform and Oracle version.

But more importantly, consider two issues:
1. How will the monitoring be done at the server level? For example if
that is the responsibility of your system administrators, then you need
to talk to them first.
2. Be cautious with the MAXSIZE limit. This can become a hidden
You think since autoextend is turned on your users won't run out of
Then months from now you get a call in the middle of the night and after
digging around you discover the MAXSIZE was hit.

Dennis Williams

On 9/21/06, genegurevich@xxxxxxxxxxxxxxxxxxxxx <
genegurevich@xxxxxxxxxxxxxxxxxxxxx> wrote:
  Hi everybody:

  I am looking into turning autoextend on on a few of my prod
  I want to make sure that
  i  understand it all correctly. I am issuing the command

  alter database datafile FILENAME autoextend on increment XXXM maxsize

  This will force Oracle to increase the size of the FILENAME by XXXM
  (assuming that
  this space is available in the filesystem) whenever the tablespace
  of space.
  It will not however affect the way the space is allocated for the
  within my
  tablespace. Am I correct here?

  thank you

  Gene Gurevich




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