Re: EXPIRE as a statement

On Sun, May 4, 2014 at 10:06 PM, Tom Lane-2 [via PostgreSQL] <
ml-node+s1045698n5802390h14(at)n5(dot)nabble(dot)com> wrote:

> David G Johnston <[hidden email]<http://user/SendEmail.jtp?type=node&node=5802390&i=0>>
> writes:
> > Blagoj Petrushev wrote
> >> I know for example that redis has this feature, the EXPIRE / EXPIREAT
> >> / TTL commands.
> >> http://redis.io/commands/expire
>
> One thought here is that recent versions of the SQL standard contain some
> temporal-data features, which might well be usable for the purposes
> envisioned here. I'd much rather see us implementing SQL-spec features
> than randomly invented ones, so please take a look into the spec before
> going too far with EXPIRE.
>
>
​Slightly different semantics between data valid over a period - but
maintained indefinitely - and data that is intentionally desired to be
physically removed from the database after a certain point.

And the temporal features require, from my recollection, require a
specified "AT point-in-time" clause whereas expiration would generally be
invisible from the viewpoint of a SELECT writer - hence why polluting
existing queries is so high a risk.

Since expires seems easier I'm not sure that, if one were to go here first,
we'd want decisions made to support the "expires" capability to bleed into
a future temporal implementation.

David J.

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