Re: Large tables, ORDER BY and sequence/index scans

>>>>> "PS" == Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> writes:

PS> Have you original values random_page_cost and seq_page_cost in
PS> postgres.conf?

Yes. To be sure I uncommented the values in postgresql.conf

seq_page_cost = 1.0 # measured on an arbitrary scale
random_page_cost = 4.0 # same scale as above

and restarted PostgreSQL. The result looks basically the same:

explain analyze declare c cursor for select * from foo2 order by value;
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------
Sort (cost=1829429.20..1854429.20 rows=9999999 width=10) (actual time=43709.313..49265.244 rows=9999999 loops=1)
Sort Key: value
Sort Method: external merge Disk: 204208kB
-> Seq Scan on foo2 (cost=0.00..154049.99 rows=9999999 width=10) (actual time=0.072..1760.585 rows=9999999 loops=1)
Total runtime: 54399.967 ms
(5 rows)