Re: Sequential vs. random values - number of pages in B-tree

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*

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