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Question: Normal index structure/size under 9i

From: DW <dwhittier_at_shaw.ca>
Date: 24 May 2005 15:59:43 -0700
Message-ID: <1116975583.298036.253570@g44g2000cwa.googlegroups.com>


Greetings:

Basic architectural question here:

I have a normal index against 4 columns of a 18.8M row table. The types of the 4 indexed columns are 3x NUMBER(10) and a DATE.

By my math, with a DATE being max 7 bytes, this adds up to 37 bytes of indexed data per row.

37 * 1.8M = 666M bytes, or rougly 680MB. That tells me that for a 1.8M table with these columns, the amount of indexed data in the index should be 680MB.

After I do a rebuild, the index size estimate (using TOAD 8) is 868MB.

So is it typical for an index to be roughly 1/3 again the size of the indexed data?

Thanks!

DW Received on Tue May 24 2005 - 17:59:43 CDT

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