Re: Bitmap index scan preread using posix_fadvise - Mailing list pgsql-patches

Attached is the correct patch, sorry for the confusion.

If anyone's interested in testing it you can do so without the randomarray.c
file by using Pavel Stehule's solution for generating arrays:

postgres=# create table h as (select (random()*1000000)::integer as r, repeat('x',512)::text as t from
generate_series(1,1000000));
SELECT

postgres=# create index hri on h(r);
CREATE INDEX

postgres=# analyze h;
ANALYZE

postgres=# \timing
Timing is on.

postgres=# set preread_pages = 0;   explain analyze select * from h where r = any (array(select
(1+random()*1000000)::integerfrom generate_series(1,100))); 
postgres=# set preread_pages = 100; explain analyze select * from h where r = any (array(select
(1+random()*1000000)::integerfrom generate_series(1,100))); 
postgres=# set preread_pages = 0;   explain analyze select * from h where r = any (array(select
(1+random()*1000000)::integerfrom generate_series(1,100))); 
postgres=# set preread_pages = 100; explain analyze select * from h where r = any (array(select
(1+random()*1000000)::integerfrom generate_series(1,100))); 
postgres=# set preread_pages = 0;   explain analyze select * from h where r = any (array(select
(1+random()*1000000)::integerfrom generate_series(1,100))); 



--
  Gregory Stark
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