From: | Oleg Bartunov <oleg(at)sai(dot)msu(dot)su> |
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To: | Pgsql Hackers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | new module contrib/tree for 7.2 ? |
Date: | 2002-01-25 14:08:38 |
Message-ID: | Pine.GSO.4.33.0201251644330.2837-100000@ra.sai.msu.su |
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Lists: | pgsql-hackers |
Hi,
Is't late to submit new contrib module for 7.2 ?
It's almost ready and tested, we have to write README.tree.
New module creates new data types 'tree', 'treequery' for tree-like data and
provides indexed access methods using Btree or GiST.
Node represents as a path to the root, so record like '3.4' means
4-th child of 3-rd child of the root node.
Due-to bit-representation there is a limitation to the number of
children - 64 and defined in compile time (valid values - 8,16,32,64).
For practical purposes 64 children looks quite enough.
insert,delete operations should be ok, while move operations
is a pain - one should update all paths of children nodes.
But search is very fast, we use data from Open Directory catalog (www.dmoz.org)
for testing:
Select all countries:
dmoz64=# explain analyze select * from dmoz where tid <* '18.*.0';
NOTICE: QUERY PLAN:
Index Scan using tid_g_idx on dmoz (cost=0.00..1094.10 rows=277 width=100) (actual time=3.54..23.76 rows=56 loops=1)
Total runtime: 23.96 msec
EXPLAIN
dmoz64=#
name | strid | id | tid
---------------------+-------------------------------+--------+-------
Tagalog | Top/World/Tagalog | 276537 | 18.18
Taiwanese | Top/World/Taiwanese | 276566 | 18.19
Tamil | Top/World/Tamil | 276567 | 18.20
Telugu | Top/World/Telugu | 276568 | 18.21
Thai | Top/World/Thai | 276601 | 18.22
Ukrainian | Top/World/Ukrainian | 276602 | 18.23
Vietnamese | Top/World/Vietnamese | 276603 | 18.24
Japanese | Top/World/Japanese | 268629 | 18.31
Kiswahili | Top/World/Kiswahili | 268630 | 18.32
Afrikaans | Top/World/Afrikaans | 256813 | 18.1
Italiano | Top/World/Italiano | 266163 | 18.30
Interlingua | Top/World/Interlingua | 266144 | 18.29
Indonesia | Top/World/Indonesia | 265859 | 18.28
Croatian | Top/World/Croatian | 257063 | 18.12
....................................................................
Regards,
Oleg
_____________________________________________________________
Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
Internet: oleg(at)sai(dot)msu(dot)su, http://www.sai.msu.su/~megera/
phone: +007(095)939-16-83, +007(095)939-23-83
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