Re: [HACKERS] Re: [HACKERS] generated columns

On 12/27/2017 09:31 AM, Peter Eisentraut wrote:
> On 9/12/17 15:35, Jaime Casanova wrote:
>> On 10 September 2017 at 00:08, Jaime Casanova
>> <jaime(dot)casanova(at)2ndquadrant(dot)com> wrote:
>>>
>>> During my own tests, though, i found some problems:
>
> Here is an updated patch that should address the problems you have found.

In the commit message it says:

"The plan to is implement two kinds of generated columns:
virtual (computed on read) and stored (computed on write). This
patch only implements the virtual kind, leaving stubs to implement
the stored kind later."

and in the patch itself:

+<para>
+ The generation expression can refer to other columns in the table, but
+ not other generated columns. Any functions and operators used must be
+ immutable. References to other tables are not allowed.
+</para>

Question -- when the "stored" kind of generated column is implemented,
will the immutable restriction be relaxed? I would like, for example, be
able to have a stored generated column that executes now() whenever the
row is written/rewritten.

Joe

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