Please don't top-post. Inline (with trim) is better but at minimum bottom-post.
On Tue, Jul 14, 2020 at 9:01 AM Marc Millas <marc.millas@xxxxxxxxxx> wrote:
Hi,your answer helps me understand my first problem.so, I rewrote a simple loop so as to avoid the "volatile" behaviour.(at least I was thinking I did... looks like I was wrong !)step by step loop:DO $$
BEGIN
FOR counter IN 1..1000 LOOP
begin
declare
id1 integer =ceiling(random()*2582);
id3 date= '2000-01-01';
id2 date;
pren varchar;
begin
id2=id3 + (random()*7200)::integer;
SELECT prenom FROM prenoms WHERE id=id1 into pren;
INSERT INTO testparttransac (datenaissance, prenoms) values(id2,pren);
end;
end;
END LOOP;
END; $$;I truncated the table, executed the loop with no errors, and expected that a select count(*)may answer 1000 !no.it varies, from less than 1000 (much less, something like 900)and more than 1000 (up to 1094)so... what s "volatile" in the loop ?
Everything...
You are setting id1 to the result of an _expression_ inside the loop. Everytime that statement gets executed within the loop a new random number is produced.
I mean, even "id 3 date = '2000-01-01'" is repeatedly casting (I think) the string to a date and assigning it to the variable even though that statement overall is effectively immutable.
David J.
