[ZODB-Dev] [ zodb-Bugs-555575 ] BTree.keys() failure

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Bugs item #555575, was opened at 2002-05-13 14:48
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Tim Peters (tim_one)
Assigned to: Nobody/Anonymous (nobody)
Summary: BTree.keys() failure

Initial Comment:
Here's a "sharp" test case that fails on my box 
(Windows, Python 2.1, Zope TextIndexDS9-branch).  
Guido reported failure on Linux too:

. b = IOBTree()
. for i in xrange(29972): # works if 29971
.     b[i] = i
. for i in xrange(30): # works if 29
.     del b[i]
.     b[i+40000] = i
. print 'len(b)', len(b)
. print 'len(b.keys())', len(b.keys())
. print 'b.keys()[0]', b.keys()[0] # IndexError

That does not fail using an IIBTree, but this does:

. b = IIBTree()
. for i in xrange(29972*2):
.     b[i] = i
. for i in xrange(30*2):
.     del b[i]
.     b[i+40000*2] = i
. print 'len(b)', len(b)
. print 'len(b.keys())', len(b.keys())
. print 'b.keys()[0]', b.keys()[0] # IndexError

It's the same thing, except the trip counts have 
doubled.  I assume, but don't know, that this is 
related to that DEFAULT_MAX_BUCKET_SIZE is twice as 
large in _IIBTree.c than in _IOBTree.c.

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>Comment By: Tim Peters (tim_one)
Date: 2002-05-13 15:19

Message:
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Yes, I see that the first test case above fails in the same 
way after s/IOBTree/OOBTree/.  This isn't surprising given 
how the various BTree flavors are implemented (the same 
basic code gets compiled over and over, with macro 
substitutions for key and value copying, and key 
comparison).

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Comment By: Neil Schemenauer (nascheme)
Date: 2002-05-13 14:57

Message:
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user_id=35752

Does this happen for OOBTrees as well?  We saw a failure
similar to this on our site after a rogue spider
created thousands of sessions (stored in a OOBTree).

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