slow array(subselect)

Hi

Just curious

postgres=# explain analyze select array_upper(array_agg(i),1) from
generate_series(1,100000) g(i);
QUERY
PLAN
---------------------------------------------------------------------------------------------------------------------------------
Aggregate (cost=12.50..12.52 rows=1 width=4) (actual time=43.164..43.164
rows=1 loops=1)
-> Function Scan on generate_series g (cost=0.00..10.00 rows=1000
width=4) (actual time=19.150..31.083 rows=100000 loops=1)
Planning time: 0.100 ms
Execution time: 44.392 ms
(4 rows)

postgres=# explain analyze select array_upper(array(select i from
generate_series(1,1000000) g(i)),1);
QUERY
PLAN
--------------------------------------------------------------------------------------------------------------------------------------
Result (cost=10.00..10.01 rows=1 width=4) (actual time=334.567..334.568
rows=1 loops=1)
InitPlan 1 (returns $0)
-> Function Scan on generate_series g (cost=0.00..10.00 rows=1000
width=4) (actual time=141.503..254.483 rows=1000000 loops=1)
Planning time: 0.171 ms
Execution time: 339.057 ms
(5 rows)

This code is about 8times slower

Regards

Pavel