Test-1
---------
DO $$
DECLARE count integer;
BEGIN
For count In 1..1000000 Loop
Execute 'explain Select ten from tenk1';
END LOOP;
END;
$$;

Head
--------
Time: 21228.829 ms (00:21.229)
Time: 21353.244 ms (00:21.353)
Time: 21758.958 ms (00:21.759)
Time: 20999.708 ms (00:21.000)
Time: 21804.451 ms (00:21.804)
Time: 20851.715 ms (00:20.852)
Time: 21514.198 ms (00:21.514)
Time: 20677.121 ms (00:20.677)
Time: 21685.576 ms (00:21.686)
Time: 21050.080 ms (00:21.050)

Patches (upto 0003)
--------------------------
Time: 23425.923 ms (00:23.426)
Time: 21609.624 ms (00:21.610)
Time: 21865.652 ms (00:21.866)
Time: 22006.988 ms (00:22.007)
Time: 22427.953 ms (00:22.428)
Time: 23195.211 ms (00:23.195)
Time: 22692.508 ms (00:22.693)
Time: 21757.227 ms (00:21.757)
Time: 22574.941 ms (00:22.575)
Time: 22496.439 ms (00:22.496)
Time: 21648.699 ms (00:21.649)

Patches (upto 0005)
---------------------------
Time: 23003.406 ms (00:23.003)
Time: 22624.973 ms (00:22.625)
Time: 22426.394 ms (00:22.426)
Time: 22700.590 ms (00:22.701)
Time: 22452.472 ms (00:22.452)
Time: 23048.367 ms (00:23.048)
Time: 21845.491 ms (00:21.845)
Time: 22832.643 ms (00:22.833)
Time: 21995.769 ms (00:21.996)
Time: 22441.257 ms (00:22.441)

Test-2
-------
DO $$
DECLARE count integer;
BEGIN
For count In 1..1000000 Loop
Execute 'explain select hundred,ten from tenk1 order by hundred';
END LOOP;
END;
$$;

Head
-----
Time: 32229.360 ms (00:32.229)
Time: 33310.348 ms (00:33.310)
Time: 32712.002 ms (00:32.712)
Time: 32630.473 ms (00:32.630)
Time: 33097.111 ms (00:33.097)
Time: 32487.799 ms (00:32.488)
Time: 33195.718 ms (00:33.196)
Time: 33166.606 ms (00:33.167)
Time: 32533.331 ms (00:32.533)
Time: 33335.595 ms (00:33.336)

Patches (upto 0003)
------------------
Time: 34715.029 ms (00:34.715)
Time: 34711.412 ms (00:34.711)
Time: 33489.049 ms (00:33.489)
Time: 34486.523 ms (00:34.487)
Time: 33946.198 ms (00:33.946)
Time: 33630.632 ms (00:33.631)
Time: 33547.556 ms (00:33.548)
Time: 34417.672 ms (00:34.418)
Time: 33921.339 ms (00:33.921)
Time: 33815.198 ms (00:33.815)

Patch (upto 0005)
------------------
Time: 33686.723 ms (00:33.687)
Time: 34701.752 ms (00:34.702)
Time: 33747.216 ms (00:33.747)
Time: 34400.340 ms (00:34.400)
Time: 34378.550 ms (00:34.379)
Time: 34855.390 ms (00:34.855)
Time: 33538.599 ms (00:33.539)
Time: 34292.776 ms (00:34.293)
Time: 34062.697 ms (00:34.063)
Time: 33310.856 ms (00:33.311)