Re: Stable function semantics (was Re: Mislabeled timestamp functions) - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Stable function semantics (was Re: Mislabeled timestamp functions)
Date
Msg-id 7887.1096838845@sss.pgh.pa.us
Whole thread Raw
In response to Mislabeled timestamp functions (was Re: [SQL] [NOVICE] date_trunc'd timestamp index possible?)  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Oliver Jowett <oliver@opencloud.com> writes:
> Bruno Wolff III wrote:
>> I should have said within a single statement instead of within a single
>> transaction.

> As I understand Tom's earlier explanation of this, the definition is 
> even more narrow: stable functions only need to return the same value 
> across a single tablescan.

> It might be useful to have some variant of stable (or perhaps just a 
> change in semantics) such that the function returns the same value for 
> identical parameters until the next CommandCounterIncrement.

In practice I think these are equivalent definitions.
        regards, tom lane


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