Re: Two Issues

On Mon, 10 Feb 2003 09:44:30 +0000, Norman Dunbar wrote:

> Morning/Evening Howard,
>
>>> 1. In Linux, what's a 'segmentation fault'?
>
> segmentation fault n.
> [Unix] 1. [techspeak] An error in which a running program attempts to
> access memory not allocated to it and core dumps with a segmentation
> violation error. This is often caused by improper usage of pointers in
> the source code, dereferencing a null pointer, or (in C) inadvertently
> using a non-pointer variable as a pointer. The classic example is:
>
> int i;
> scanf ("%d", i); /* should have used &i */
>

Yup. Clear as mud. ;-)

> 2. To lose a train of thought or a line of reasoning. Also uttered as an
> exclamation at the point of befuddlement.

Uh huh. That about sums up Linux.

>
>>> why do I get one (the story is I run emca, request to create a
> repository in an existing database (which
>>> does, and it's running), specify to log on as SYS, supply a service
> name, click <next>.
>>> Bang! I would like to know where to start diagnosing such a problem).
>
> Could well be a programming problem, a Java RTL problem or perhaps, a
> ulimit limit. What do you get for ulimit -m? (or ulimit -a) which shows
> the amount of memory a process is allowed to have.

Oh, OK. I get this:

$ulimit -m
$unlimited

and this:

$ulimit -a
core file size (blocks, -c) 0
data seg size (kbytes, -d) unlimited
file size (blocks, -f) unlimited
max locked memory (kbytes, -l) unlimited max memory size (kbytes, -m) unlimited
open files (-n) 1024
pipe size (512 bytes, -p) 8
stack size (kbytes, -s) unlimited
cpu time (seconds, -t) unlimited
max user processes (-u) 4607
virtual memory (kbytes, -v) unlimited

I wish I could say I knew what this means. I've searched through my 'learn Redhat in a weekend' book for ulimit. Sod all. I've pored through by 'Red Hat : The Complete Reference'. Sod all. Some new meaning of the word 'complete', I guess.

>It could be too
> small.

Unlimited sounds pretty good to me, though how I can have unlimited swap size when I know damn well I only formatted a 2GB swap partition, I have no idea!!

>You can use ulimit to set a limit but you can only set it up to
> the kernel configured limits. If you need more, reconfigure and rebuild
> the kernel. [Ahem, did you read the pre-installations docs !! (Sorry)
> :o) ]

Well, no actually. I had some install instructions for SuSe 7.1. And I adjusted them slightly for doing Mandrake and Red Hat. I certainly needed to set sem (cd /proc/sys/kernel. echo some numbers > sem). And I also set shmmax somewhere. But yes, I need to look at them all at some point.

But at least I don't get ORA-03113!!!

>
>>> 2. When in desperation I run emca and tell it to create a new
> repository,
>>> typical <SNIP> I get this error message:
>>>
>>> Invalid entry size (expected 143527936 but got 143527951 bytes)
>>>
>
> I wonder if this is a reference to the size of memory that the process
> requires ?
> Sorry, can't be more helpful here !
>

Fair enough. To me it looks like what I'd call a DLL version problem on Windows. That the code says to call something at offset X, and actually in the new DLL it's at offset Y.

And then I recall seeing a website about installing 9i on Redhat 8, and mentioning 'make sure you have binutils version 10' or some such thing. And I downloaded said binutils. And I didn't bother to install them, since the installation went OK, and I can create customised databases with aplomb.  

>
>>> I had this exact same error message on Mandrake 9.0, but this is
> Redhat
>>> 8.0. How come my byte knickers are in a twist?
>
> Mandrake is basically RedHat I believe.
>

Well, I'd hope so... they're supposed to be the same O/S after all!! But RH8 uses 2.4.18, and Mandrake uses 2.4.19 (if memory serves).

>
>>> Incidentally, I have to confess with some amazement that on my crappy
>>> laptop, Oracle on Linux is running appreciably faster than it was on
>>> Windows (same crappy laptop).
>>> <SNIP>It's certainly going like the clappers here.
>
> I managed to get my Windows setup running 9iR2 EE running like a fast
> thing simply by adding an extra 512 MB RAM. I've only got a 400 horse
> power processor at home, but the memory upgrade makes soooooooo much
> difference.

All my boxes already have 2GB of RAM, minimum. And yes, Windows ripped along. But Oracle on Linux is making Oracle on Windows look like a slug in a wheelchair with its brakes on, running over some freshly-poured tarmac on a really hot day.

>I'm getting the download stuff for Unix so I can see how it
> goes on that. At work, I have a new 1700 horse power processor and 9iR2
> EE runs like a dog in 256 MB.
>
>
>>> Calling all Linux gurus!!
>
> Sorry, you got me instead !

Always a pleasure, actually.

Regards
HJR Received on Mon Feb 10 2003 - 14:47:56 CST