Re: Function Volatility Stable vs Immutable

Поиск
Список
Период
Сортировка
От David G. Johnston
Тема Re: Function Volatility Stable vs Immutable
Дата
Msg-id CAKFQuwZ1JF7+cS2O5ZpepQrJavMAsRr5cUfW3wYQHEpeEddjLw@mail.gmail.com
обсуждение исходный текст
Ответ на Function Volatility Stable vs Immutable  ("Igal @ Lucee.org" <igal@lucee.org>)
Ответы Re: Function Volatility Stable vs Immutable  ("Igal @ Lucee.org" <igal@lucee.org>)
Список pgsql-general
On Mon, Jun 24, 2019 at 7:31 PM Igal @ Lucee.org <igal@lucee.org> wrote:
If a function select data from a table, and the rows in the table may
change, would that function qualify for Immutable or does it have to be
Stable?  I'm asking because according to the docs [1]: "An IMMUTABLE
function cannot modify the database and is guaranteed to return the same
results given the same arguments forever".

So for the same arguments, the result would change only if the data in
the table changes.  Does that mean that it violates the "forever" clause
and therefore can be only marked as Stable and not Immutable?

Yes

Forever means beyond the lifetime of a single transaction and thus it is possible for the changing of the table contents to impact the return value of the function.

David J.

В списке pgsql-general по дате отправления:

Предыдущее
От: "Igal @ Lucee.org"
Дата:
Сообщение: Function Volatility Stable vs Immutable
Следующее
От: "Igal @ Lucee.org"
Дата:
Сообщение: Re: Function Volatility Stable vs Immutable