Re: Maximum height of an Oracle B-tree index

From: Tanel Põder <tanel.poder.003_at_mail.ee>
Date: Sat, 27 Mar 2004 17:17:53 +0200
Message-ID: <012b01c4140e$ad519880$6df923d5@porgand>

Hi!

Actually it seems that yes, there are 3 bits reserved for flags in kdxcolev structure. When you do a blockdump for an index branch and leaf, you see the following (9.2)

Branch block dump

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header address 116658244=0x6f41044
kdxcolev 2
KDXCOLEV Flags = - - -

You see that there two lines printed for kdxcolev structure and there is is three dashes for Flags in KDXCOLEV... So, this would mean 5 bits for height and 3 for other stuff. Could it be that Oracle used values 24 to 31 in the first 5 bits also for special meaning in latter versions, since they had already used up all of the bits and the architects thought 24 levels would be sufficient anyway?

I can't think of any other reason for having 24 distinct value limit in 5 bit space.

Tanel.

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Received on Sat Mar 27 2004 - 09:15:23 CST