Re: Determine potential change in table size after a column dropped?

Hi Holger Jakobs,

Thank you so much for your quick reply and instruction. I will try later.

Have a nice day.

Br, Ji

On Tue, 1 Feb 2022 at 14:49, Holger Jakobs <holger(at)jakobs(dot)com> wrote:

> Am 01.02.22 um 14:46 schrieb Jiankang Ji:
>
> Hi All Supermen Experts,
>
> I'm new in pgsql and have a similar problem for a timescale pgDB. A DB
> table is for storing raw sessions data received through IoT network from
> many remote machines. The data format is the same for all the machines but
> the sessions lasting-periods could be different from 1 minute to 1 hour and
> such. Each machine could be activated once a day or a few times a day
> randomly.
>
> My question is:
> 1. How to setup a watch-dog to detect new data has been added into the DB,
> and
> 2. How to pick-up the newly completed sessions data since last pick-up and
> put it into a buffer table dedicated to new data for further ETL processing?
>
> If you have some scripts in pgSQL, Python or C, it will be greatly
> appreciated!
>
> Thank you.
>
> Best regards, Ji
>
>
>
>> In order to get notified should new rows arrive (or current ones updated
> or deleted), you can install a trigger which fires a NOTIFY command on a
> name (channel).
>
> All other sessions which have issued a LISTEN on the same name (channel)
> will receive a notification.
>
> Unfortunately, not all languages and drivers support this.
>
> Recently, I updated the code for pg_listen in the script language Tcl.
> It's committed, but no new version released yet.
>
>
> --
> Holger Jakobs, Bergisch Gladbach, Tel. +49-178-9759012
>
>