Hi all, May be I completely wrong but I always assumed that the access speed to the array element in PostgreSQL should be close to constant time. But in tests I found that access speed degrade as O(N) of array size.
Test case (performed on large not busy server with 1GB work_mem to ensure I working with memory only): WITH t AS (SELECT ARRAY(SELECT * FROM generate_series(1,N)) AS _array) SELECT count((SELECT _array[i] FROM t)) FROM generate_series(1,10000) as g(i); Results for N between 1 and 10.000.000 (used locally connected psql with \timing): N: Time: 1 5.8ms 10 5.8ms 100 5.8ms 1000 6.7ms --until there all reasonable 5k 21ms 10k 34ms 50k 177ms 100k 321ms 500k 4100ms 1M 8100ms 2M 22000ms 5M 61000ms 10M 220000ms = 22ms to sinlge array element access. Is that behaviour is correct? PS: what I actually lookin for - constant fast access by position tuplestore for use with recursive queries and/or pl/pgsql, but without using C programming. -- Maxim Boguk Senior Postgresql DBA. Phone RU: +7 910 405 4718 Phone AU: +61 45 218 5678 Skype: maxim.boguk Jabber: maxim.bo...@gmail.com МойКруг: http://mboguk.moikrug.ru/ "People problems are solved with people. If people cannot solve the problem, try technology. People will then wish they'd listened at the first stage."
