Re: Add generate_series(numeric, numeric)
| От | Ali Akbar |
|---|---|
| Тема | Re: Add generate_series(numeric, numeric) |
| Дата | |
| Msg-id | CACQjQLraP1njx=T_LY4jLimRwQGGuT3W9JG7G1N-P5JpUwh8LA@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: Add generate_series(numeric, numeric) (Michael Paquier <michael.paquier@gmail.com>) |
| Ответы |
Re: Add generate_series(numeric, numeric)
|
| Список | pgsql-hackers |
Thanks for the review. Attached the formatted patch according to your suggestion.
- numeric datatype is large, but there are limitations. According to doc, the limit is: up to 131072 digits before the decimal point; up to 16383 digits after the decimal point. How can we check if the next step overflows? As a comparison, in int.c, generate_series_step_int4 checks if its overflows, and stop the next call by setting step to 0. Should we do that?
Yes we should.
how can we check the overflow after add_var?
(in int.c, the code checks for integer calculation overflow, that wraps the result to negative value)
(in int.c, the code checks for integer calculation overflow, that wraps the result to negative value)
in numeric.sql regression test, i've added this query:
select (i / (10::numeric ^ 131071))::numeric(1,0)
from generate_series(-9*(10::numeric ^ 131071),
9*(10::numeric ^ 131071),
(10::numeric ^ 131071))
as a(i);
select (i / (10::numeric ^ 131071))::numeric(1,0)
from generate_series(-9*(10::numeric ^ 131071),
9*(10::numeric ^ 131071),
(10::numeric ^ 131071))
as a(i);
Because the doc notes that the maximum numeric digit before decimal point is 131072, i hope this query covers the overflow case (in the last value it will generate, if we add 9 x 10^13071 with 10^13071, add_var will overflows). But in my tests, that isn't the case. The code works without any error and returns the correct rows:
numeric
---------
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
7
8
9
(19 rows)
numeric
---------
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
7
8
9
(19 rows)
Regards,
--
Ali Akbar
Ali Akbar
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