2008-11-21
fgmailbox
发件人： fgmailbox
发送时间：
2008-11-21 11:41:59
收件人： 49259BE6.8010704;
joaquin
抄送：
主题： Re: [Boost-users]
[multiindex] Why not to add B+Tree index to multiIndex?
To: "boost-users@lists.boost.org" <boost-users@lists.boost.org>
Message-ID: <49259BE6.8010704@tid.es>
Content-Type: text/plain; charset=GB2312
fgmailbox escribi??:
> we can use multiindex as a memory db,but the multiindex only support
> hash index and Order index(RB TREE),why not to add b+ Tree Index to
> multiindex to make it much faster .
I'm no expert in B+ trees, but I understand that these structures are
more effective than regular binary trees when secondary storage (i.e.
hard disk) is used, which is not the case for an in-memory container
like multi_index_container. Have you any reference on the performance
of B+ trees in in-memory scenarios?
Joaqu??n M L??pez Mun~oz
Telef??nica, Investigaci??n y Desarrollo
Hi joaquin:
I found b+ Tree code in a GNU Database Source
Code of [firebird] Database code
template
< typename Value, typename Key = Value, typename Allocator = MallocAllocator,
typename KeyOfValue = DefaultKeyValue<Value>,
typename Cmp = DefaultComparator<Key>,
int LeafCount = LEAF_PAGE_SIZE / sizeof(Value),
nt NodeCount = NODE_PAGE_SIZE / sizeof(void*)
>
class BePlusTree {....}
the Allocator can be a memory allocator or a disk
file allocator,so this template can use as a memory database
index
,and I have use the template to test BePlusTree
and stl::set to test performance, the BePlusTree is faster than set in the
condition of large scale data query.
2008-11-21
fgmailbox