postgresql/contrib/intarray
Tom Lane bf56f0759b Make OIDs optional, per discussions in pghackers. WITH OIDS is still the
default, but OIDS are removed from many system catalogs that don't need them.
Some interesting side effects: TOAST pointers are 20 bytes not 32 now;
pg_description has a three-column key instead of one.

Bugs fixed in passing: BINARY cursors work again; pg_class.relhaspkey
has some usefulness; pg_dump dumps comments on indexes, rules, and
triggers in a valid order.

initdb forced.
2001-08-10 18:57:42 +00:00
..
bench Update contrib intarray to Jan 25 version. 2001-03-17 21:59:42 +00:00
data 1. Fixed error with empty array ( '{}' ), 2001-08-04 19:35:32 +00:00
expected Repair intarray's problems with TOASTed input, avoid scribbling on 2001-03-20 03:08:12 +00:00
sql Update contrib intarray to Jan 25 version. 2001-03-17 21:59:42 +00:00
_int.c Looks okay in a quick glance, except error message spelling is poor: 2001-08-04 19:36:45 +00:00
_int.sql.in Make OIDs optional, per discussions in pghackers. WITH OIDS is still the 2001-08-10 18:57:42 +00:00
Makefile The attached patch enables the contrib subtree to build cleanly under 2001-06-18 21:38:02 +00:00
README.intarray Repair intarray's problems with TOASTed input, avoid scribbling on 2001-03-20 03:08:12 +00:00

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 provides index 
support for one-dimensional array of int4's - gist__int_ops, suitable for
small and medium size of arrays (used on default), and gist__intbig_ops for 
indexing large arrays (we use superimposed signature with length of 4096 
bits to represent sets). 

All work was done by Teodor Sigaev (teodor@stack.net) and Oleg Bartunov
(oleg@sai.msu.su). See http://www.sai.msu.su/~megera/postgres/gist
for additional information.

CHANGES:

March 19, 2001
   1. Added support for toastable keys
   2. Improved split algorithm for intbig (selection speedup is about 30%)

INSTALLATION:

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

REGRESSION TEST:

   gmake installcheck

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 gist__int_ops) 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;

BENCHMARK:

  subdirectory bench contains benchmark suite.
  cd ./bench
  1. createdb TEST
  2. psql TEST < ../_int.sql
  3. ./create_test.pl | psql TEST
  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|
+----------+-------+-------+--------+-------+