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From: Pei Cao <pc%cs.Princeton.EDU@Princeton.EDU>
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Date: Wed, 31 Aug 1994 23:56:08 -0400
Message-Id: <9409010356.AA04017@cs>
To: postgres@postgres.Berkeley.EDU
Subject: how are key values stored in a B-tree index files?
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Resent-Date: Wed, 31 Aug 94 20:56:21 -0700
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Hi, I am trying to figure out how the B-tree index file works.  I have a
relation with a non-clustered unique integer key, and I built a B-tree index
on it.  I'd like to figure out from the index files what disk pages/blocks 
have tuples whose key values are between, say, 500 and 600.  

So I used "pagedoc -b -d2 index" to dump the index file contents.
The problem is, it seems that each IndexTupleData only has the tid of the 
corresponding heap tuple, but no key value of this heap tuple.  So how does a 
search for a tuple with a particular key work?  

I don't even see the key values on internal pages, so how does a search know
which direction to go down the b-tree?

Thanks a lot!

Pei Cao
Grad. Student, CS Dept.
Princeton University

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