[Zope-dev] BTree upgrading

[Chris McDonough]

This looks about right.  Threshhold is the number of key-value pairs moved
before a subcommit and cache flush, I believe.  So 200 should be OK...
probably higher, even.

----- Original Message -----
From: "Chris Withers" <chrisw@nipltd.com>
To: <zope-dev@zope.org>
Sent: Wednesday, April 04, 2001 9:51 AM
Subject: [Zope-dev] BTree upgrading


> Hi,
>
> I see the new catalog stuff makes use of new BTrees. I presume the big
> advantages the new catalog has are from these new BTrees. I know of a few
> products which also use these BTrees (Squishdot and some internal ones
here
> spring to mind) so I guess they should be upgraded too?
>
> Well, I had a look at the _convertBTrees method in Catalog.py and it all
made
> sense, so I'm guessing the folowing would be the correct way to convert
some
> BTrees?
>
> from BTrees import IOBTree, BTree, convert
>
> myBTree
>
> if type(myBTree is not IOBTree):
>   mynewBTree = IOBTree()
>   convert(myBTree,mynewBTree, 200)
>
> ...or..
>
> if type(myBTree is not BTree):
>   mynewBTree = BTree()
>   convert(myBTree,mynewBTree, 200)
>
> I'm guessing the 200 is how many items get put in each bucket? What should
> influence the choice of this number?
>
> cheers,
>
> Chris
>
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