Comment 28 for bug 405251

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Frits Jalvingh wrote:
> heads:

> ==> 5330e96e278ff9ea7408111227e0c8b1.tix <==
> B+Tree Graph Index 2
> node_ref_lists=2
> key_elements=2
> len=19
> row_lengths=1
>

> ==> 99a0078750de654f7eee8188ec397f4a.tix <==
> B+Tree Graph Index 2
> node_ref_lists=2
> key_elements=2
> len=785402
> row_lengths=1,83,12950
>
> I will do the patch from #26 in 1.17; and do the full copy again in an
> empty repo, with trees (like before).
>

so 19 + 785,402 = 785,421 or almost 800k nodes

Also, for indexes, we keep a cache of 1,000 "nodes". And you can see
that this last one is >10,000 nodes, which means our cache hit rate is
going to be quite low.

If you want to try something else, you could do:

=== modified file 'bzrlib/btree_index.py'
- --- bzrlib/btree_index.py 2009-07-01 10:51:47 +0000
+++ bzrlib/btree_index.py 2009-08-06 01:46:03 +0000
@@ -46,7 +46,7 @@
 _PAGE_SIZE = 4096

 # 4K per page: 4MB - 1000 entries
- -_NODE_CACHE_SIZE = 1000
+_NODE_CACHE_SIZE = 20000

John
=:->

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