RD-Tree, index support for int array (contrib-intarray)

Hi,

I attached archive with contrib-intarray. Please submit it into
7.1 beta source tree.

Here is README
--------------------------------------------------------------
This is an implementation of RD-tree data structure using GiST interface
of PostgreSQL. It has built-in lossy compression - must be declared
in index creation - with (islossy). Current implementation has index support
for one-dimensional array of int4's.
All works was done by Teodor Sigaev (teodor@stack.net) and Oleg Bartunov
(oleg@sai.msu.su).

INSTALLATION:
 gmake gmake install -- load functions psql <database> < _int.sql

EXAMPLE USAGE:
 create table message (mid int not null,sections int[]); create table message_section_map (mid int not null,sid int not
null);
 -- create indices
CREATE unique index message_key on message ( mid );
CREATE unique index message_section_map_key2 on message_section_map (sid, mid );
CREATE INDEX message_rdtree_idx on message using gist ( sections ) with ( islossy);
 -- select some messages with section in 1 OR 2 - OVERLAP operator select message.mid from message where
message.sections&& '{1,2}';
 
 -- select messages contains in sections 1 AND 2 - CONTAINS operator select message.mid from message where
message.sections@ '{1,2}'; -- the same, CONTAINED operator select message.mid from message where '{1,2}' ~
message.sections;

TEST:
 subdirectory test contains test suite. cd ./test 1. createdb TEST 2. psql TEST < ../_int.sql 3. ./create_test.pl |
psqlTEST 4. ./bench.pl - perl script to benchmark queries, supports OR, AND queries                 with/without
RD-Tree.Run script without arguments to                 see availbale options.
 
    a)test without RD-Tree (OR)      ./bench.pl -d TEST -s 1,2 -v    b)test with RD-Tree      ./bench.pl -d TEST -s 1,2
-v-r
 

BENCHMARKS:

Size of table <message>: 200000
Size of table <message_section_map>: 268538

Distribution of messages by sections:

section 0: 73899 messages
section 1: 16298 messages
section 50: 1241 messages
section 99: 705 messages

old - without RD-Tree support,
new - with RD-Tree

+----------+---------------+----------------+
|Search set|OR, time in sec|AND, time in sec|
|          +-------+-------+--------+-------+
|          |  old  |  new  |   old  |  new  |
+----------+-------+-------+--------+-------+
|         1|  1.427|  0.215|       -|      -|
+----------+-------+-------+--------+-------+
|        99|  1.029|  0.018|       -|      -|
+----------+-------+-------+--------+-------+
|       1,2|  1.829|  0.334|   5.654|  0.042|
+----------+-------+-------+--------+-------+
| 1,2,50,60|  2.057|  0.359|   5.044|  0.007|
+----------+-------+-------+--------+-------+

Regards,    Oleg
_____________________________________________________________
Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(095)939-16-83, +007(095)939-23-83