intarray This is an implementation of RD-tree data structure using GiST interface of PostgreSQL. It has built-in lossy compression. Current implementation provides index support for one-dimensional array of integers: gist__int_ops, suitable for small and medium size of arrays (used by default), and gist__intbig_ops for indexing large arrays (we use superimposed signature with length of 4096 bits to represent sets). There is also a non-default gin__int_ops for GIN indexes on integer arrays. int icount(int[]) - the number of elements in intarray test=# select icount('{1,2,3}'::int[]); icount -------- 3 (1 row) int[] sort(int[], 'asc' | 'desc') - sort intarray test=# select sort('{1,2,3}'::int[],'desc'); sort --------- {3,2,1} (1 row) int[] sort(int[]) - sort in ascending order int[] sort_asc(int[]),sort_desc(int[]) - shortcuts for sort int[] uniq(int[]) - returns unique elements test=# select uniq(sort('{1,2,3,2,1}'::int[])); uniq --------- {1,2,3} (1 row) int idx(int[], int item) - returns index of first intarray matching element to item, or '0' if matching failed. test=# select idx('{1,2,3,2,1}'::int[],2); idx ----- 2 (1 row) int[] subarray(int[],int START [, int LEN]) - returns part of intarray starting from element number START (from 1) and length LEN. test=# select subarray('{1,2,3,2,1}'::int[],2,3); subarray ---------- {2,3,2} (1 row) int[] intset(int4) - casting int4 to int[] test=# select intset(1); intset -------- {1} (1 row) Operator Description int[] && int[] overlap - returns TRUE if arrays have at least one common element int[] @> int[] contains - returns TRUE if left array contains right array int[] <@ int[] contained - returns TRUE if left array is contained in right array # int[] returns the number of elements in array int[] + int push element to array ( add to end of array) int[] + int[] merge of arrays (right array added to the end of left one) int[] - int remove entries matched by right argument from array int[] - int[] remove right array from left int[] | int returns intarray - union of arguments int[] | int[] returns intarray as a union of two arrays int[] & int[] returns intersection of arrays int[] @@ query_int returns TRUE if array satisfies query (like '1&(2|3)') query_int ~~ int[] returns TRUE if array satisfies query (commutator of @@) (Before PostgreSQL 8.2, the containment operators @> and <@ were respectively called @ and ~. These names are still available, but are deprecated and will eventually be retired. Notice that the old names are reversed from the convention formerly followed by the core geometric datatypes!) 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); -- 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; 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 -c -s 1,2 -v b)test with RD-Tree ./bench.pl -d TEST -c -s 1,2 -v -r BENCHMARKS: Size of table <message>: 200000 Size of table <message_section_map>: 269133 Distribution of messages by sections: section 0: 74377 messages section 1: 16284 messages section 50: 1229 messages section 99: 683 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| 0.625| 0.101| -| -| +----------+-------+-------+--------+-------+ | 99| 0.018| 0.017| -| -| +----------+-------+-------+--------+-------+ | 1,2| 0.766| 0.133| 0.628| 0.045| +----------+-------+-------+--------+-------+ | 1,2,50,65| 0.794| 0.141| 0.030| 0.006| +----------+-------+-------+--------+-------+ All work was done by Teodor Sigaev (teodor@stack.net) and Oleg Bartunov (oleg@sai.msu.su). See for additional information. Andrey Oktyabrski did a great work on adding new functions and operations.