Francisco Olarte wrote > It's already been told that btrees work that way, if you find itstrange > read a bit about them, this is completely normal, but ...
I am just surprised by the order of magnitude in the difference though. 2 and 27 minutes that's the huge difference...I did another, simplified test, to make sure there is no duplicates and the only difference between both sets is the order: CREATE TABLE source_sequential AS SELECT s from generate_series(1,10000000) as s; CREATE TABLE source_random AS SELECT * from source_sequential ORDER BY random();CREATE TABLE t_sequential (id bigint);CREATE INDEX i_sequential ON t_sequential (id);CREATE TABLE t_random (id bigint);CREATE INDEX i_random ON t_random (id);INSERT INTO t_sequential SELECT * FROM source_sequential;*102258,949 ms*INSERT INTO t_random SELECT * FROM source_random;*1657575,699 ms* -- View this message in context: http://postgresql.nabble.com/Sequential-vs-random-values-number-of-pages-in-B-tree-tp5916956p5917292.html Sent from the PostgreSQL - general mailing list archive at Nabble.com.
