Re: Incorrect results from numeric round() and trunc() - Mailing list pgsql-hackers

From Joel Jacobson
Subject Re: Incorrect results from numeric round() and trunc()
Date
Msg-id c1ab12df-1357-4469-9761-9355015c039b@app.fastmail.com
Whole thread Raw
In response to Incorrect results from numeric round() and trunc()  (Dean Rasheed <dean.a.rasheed@gmail.com>)
Responses Re: Incorrect results from numeric round() and trunc()
List pgsql-hackers
On Sun, Jul 7, 2024, at 13:28, Dean Rasheed wrote:
> I've also tidied up a bit by replacing all instances of SHRT_MAX with
> a new constant NUMERIC_WEIGHT_MAX, whose name more accurately
> describes the limit, as used in various other overflow checks.

Having thought a bit more on this, I think we probably need a
DEC_DIGITS sensitive definition of NUMERIC_WEIGHT_MAX,
since per spec the max range for numeric is 0x20000 (131072)
decimal digits.

Therefore, I think perhaps what we want is:

+#define NUMERIC_DSCALE_MIN                     0
+#define NUMERIC_WEIGHT_MAX                     ((0x20000/DEC_DIGITS)-1)
+#define NUMERIC_WEIGHT_MIN                     (-(NUMERIC_DSCALE_MAX+1)/DEC_DIGITS)

Maybe also 0x20000 (131072) should be a defined constant.

Regards,
Joel



pgsql-hackers by date:

Previous
From: Michael Paquier
Date:
Subject: Re: Pluggable cumulative statistics
Next
From: Richard Guo
Date:
Subject: Re: report a typo in comments of ComputeXidHorizonsResult