Re: Time-based trigger

On 09/18/2012 10:03 AM, Szymon Guz wrote:
> On 18 September 2012 17:59, Robert Sosinski
> <rsosinski@ticketevolution.com <mailto:rsosinski@ticketevolution.com>>
> wrote:
>
>     We have a table, which has items that can be put on hold of 5
>     minutes (this is for an online store) once they are placed into a
>     cart.  What we need is for this hold to automatically expire after 5
>     minutes.  Right now, we put a time stamp into the row (called
>     hold_until) at 5 minutes into the future, and select items where
>     hold_until is less then now().
>
>     Would it be possible to change this to using a boolean that is set
>     to true when item is put on hold, and have something like a
>     time-based trigger automatically update the held boolean to false
>     after 5 minutes pass.
>
>     Thanks,
>
>     --
>     Robert Sosinski
>
>
> It is not possible right now, however I'd rather create some cron job
> which updates the boolean value if needed and runs each minute.
>
> - Szymon
Yeah, seems like a boolean would give no indication of when it was set.
I would rather have value "held_at" as a timestamp and the cron job
would null those "held_at" more than 5 minutes ago.  Not sure if an
index on "held_at" would help in "select where held_at is not null".