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Home -> Community -> Usenet -> c.d.o.server -> Re: Help: Settle an argument regarding EXTENTS
A copy of this was sent to jdbeckerle_at_usa.net
(if that email address didn't require changing)
On Wed, 31 Mar 1999 23:27:11 GMT, you wrote:
>I have read this discussion with great interest, and will read the
>Cary Millsap paper shortly, but let me put out this simple question:
>
>Does anyone know the maximum size of an extent in Oracle 7.3.4 on
>Windows NT 4.0?
>
>The only documentation I can find is that files are limited to
>2**22 blocks, or 8GB for 2k blocks. But I can't seem to make
>an extent larger than 2047MB.
>
For example, on NT with 8.0.4:
Oracle block size: 16 Kb
Maximum blocks per datafile: 4 million
Maximum datafiles per database - depends on block size
- 20,000 datafiles for 2 Kb Oracle block size - 40,000 datafiles for 4 Kb Oracle block size - 65,536 datafiles for >= 8 Kb Oracle block sizeLargest datafile: 64 Gb (assuming 16 Kb Oracle block size) Largest database: 4 Pb (Petabytes
In 7.3, it was smaller.
Do you have any files >2gig on your system. An extent must fit in a file.
>I will now go read the paper to find out why I shouldn't even bother trying.
>
>John
>
>
>In article <922869420.14576.0.nnrp-07.9e984b29_at_news.demon.co.uk>,
> "Jonathan Lewis" <jonathan_at_jlcomp.demon.co.uk> wrote:
>> Van Messner wrote in message ...
>> > A single extent of 60gig is probably not a good idea.
>> > He probably has always built tables as he says, and that was standard
>> > thinking until maybe six months ago.
>>
>> That's a sad reflection on how slowly people learn.
>> I've been making this point in presentations for
>> the many years, people have been announcing it
>> in this newsgroup for at least the last 2 years,
>> and the Cary Millsap paper you may be thinking
>> of is dated March 7th 1996 and that says:
>> (I quote):
>>
>> More and more people have learned that
>> multiple extents bear negligible performance
>> impact upon all Oracle DML operations.
>> .......
>> The number of distinct extent sizes in a given
>> tablespace should be small; for example, only
>> one. If there is more than one extent size in a
>> tablespace, then all those extent sizes are
>> integral multiples or divisors of each other.
>>
>> --
>>
>> Jonathan Lewis
>> Yet another Oracle-related web site: www.jlcomp.demon.co.uk
>>
>>
>
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Thomas Kyte
tkyte_at_us.oracle.com
Oracle Service Industries
Reston, VA USA
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