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Re: NumericShort vs NumericLong format - Mailing list pgsql-hackers

From David G. Johnston
Subject Re: NumericShort vs NumericLong format
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Msg-id CAKFQuwbUxr-u2BT2PQ4Q_n_o0DieipneHQE+VEPML96bnR3HDQ@mail.gmail.com
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In response to NumericShort vs NumericLong format  (Amin <amin.fallahi@gmail.com>)
Responses Re: NumericShort vs NumericLong format  (Tom Lane <tgl@sss.pgh.pa.us>)
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I'll give this a go as a learning exercise for myself...

On Mon, Mar 6, 2023 at 8:47 PM Amin <amin.fallahi@gmail.com> wrote:

- How can I determine which format will be used for a numeric type?

https://github.com/postgres/postgres/blob/cf96907aadca454c4094819c2ecddee07eafe203/src/backend/utils/adt/numeric.c#L491

(the three constants are decimal 63, 63, and -64 respectively)
- What the precision and scale values should be for pgsql to use the long format? Is there a threshold?


Ones that cause the linked-to test to return false I suppose.

David J.

As an aside, for anyone more fluent than I who reads this, is the use of the word "dynamic scale" in this code comment supposed to be "display scale"?

https://github.com/postgres/postgres/blob/cf96907aadca454c4094819c2ecddee07eafe203/src/backend/utils/adt/numeric.c#L121

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