| Datafile size limit [message #50896] |
Fri, 12 April 2002 11:58  |
Winston Gutkowski
Messages: 2
Registered: April 2002
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Junior Member |
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Hi,
We're evaluating Oracle 8i on Linux (RH 7.1/7.2) and I've run into a snag when creating tablespaces: namely that the Oracle Database Create Assistant coughs if you attempt to create a tablespace with an initial size greater than 2Gb (I can't remember the error code, but the message says something about not being able to read the header record).
It would appear that this is an OS or FS restriction, since Oracle is supposed to allow me to allocate a datafile of up to 32Gb (we have 8K database blocks), so I have a few questions:
1. I'm assuming that this error will also occur if Oracle attempts to EXTEND a datafile beyong the 2Gb limit. Is there any way to (a) avoid or (b) warn me of impending doom?
2. If a tablespace is defined with more than one datafile, what is the algorithm used by Oracle for extending the tablespace (eg, does it extend each datafile in turn until it hits a limit, all at once, least recently extended, or some combination of these)?
Any information would be extremely useful, especially info on reference material. Thank you.
Winston Gutkowski
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| Re: Datafile size limit [message #50903 is a reply to message #50896] |
Fri, 12 April 2002 18:20  |
Wei Lang
Messages: 23
Registered: March 2002
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Junior Member |
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1. I'm assuming that this error will also occur if Oracle attempts to EXTEND a datafile beyong the 2Gb limit. Is there any way to (a) avoid or (b) warn me of impending doom?
Use 64 bit OS. (I think Linx has 64 bit version too.) or you can use raw partitions.
2. If a tablespace is defined with more than one datafile, what is the algorithm used by Oracle for extending the tablespace (eg, does it extend each datafile in turn until it hits a limit, all at once, least recently extended, or some combination of these)?
It extends each in turn I believe.
Hope it helps.
Wei
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| Re: Datafile size limit [message #50918 is a reply to message #50896] |
Mon, 15 April 2002 05:14 |
Sanjay
Messages: 236
Registered: July 2000
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Senior Member |
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1. I would personally NOT create a table with intial of 2GB. Most of the OS FS limit is 2GB. If you have a good storage system (disk), any table with multiple extents is not a problem. This used to be a concern some time back. But the performance degradation is minimal. I would go for a 50M initial and 50M next size. But it's all upto you. If you want something of 2 GB initial, what kind of data is this gonna have ?
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| Re: Datafile size limit [message #50931 is a reply to message #50896] |
Mon, 15 April 2002 11:54 |
Winston Gutkowski
Messages: 2
Registered: April 2002
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Junior Member |
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Thanks for your interest.
In answer to Wei:
I believe that RH7.2 is 64-bit addressable; the problem lies with the ext3 file system.
In answer to Sanjay:
The bulk will be mostly BLOB data, some of which may be quite large. Our current size estimates suggest we want to start with a DATA tablespace of around 10Gb, with room for expansion. The reason I'm asking the question is that I want to know whether it is better to have multiple fixed-size datafiles, multiple variable-sized datafiles, or some combination of both?
(I have also worked with Progress and Informix, and in some cases they recommended 1 variable + the rest fixed). If I knew a bit more about how Oracle uses and extends datafiles I would be in a better position to know what to do.
Is there any Oracle documentation about this? I have looked in the manuals, but can't find anything which covers the specific questions I'm asking.
Thanks again for your interest.
Winston Gutkowski
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