Re: How to run a task continuously in the background - Mailing list pgsql-general

On Jul 17, 2019, at 5:57 AM, Dirk Mika <Dirk.Mika@mikatiming.de> wrote:

You will have a trigger that, once new tuples are created (or older

update and so on) issues a NOTIFY.

Somewhere (within PostgreSQL or outside it) there will be a process

that issued a LISTEN and is locked until a notify comes in. Then it

does process whatever you need to do.

As an example your trigger function will be something like

<https://github.com/fluca1978/PostgreSQL-11-Quick-Start-Guide/blob/master/Chapter09/Chapter09_Listing05.sql>

and your listening process will be something like

<https://github.com/fluca1978/PostgreSQL-11-Quick-Start-Guide/blob/master/Chapter09/Chapter09_Listing09.perl>.

 

Thanks for the examples. I’ll look into them.

 

This makes your processing fully asynchronous, and with some tune

allows you to decide the start/stop/resume policy as you need/wish.

 

Besides, it is quite hard for me to get to the point where you need to

check for new data every second, and therefore why you are not

satisfied with pg_cron or stuff like that.

 

pg_cron doesn’t start the task instantly and queues subsequent runs, if the task is still running. I just need to start the task once and it should keep running until stopped / killed.

 

Maybe I'll have to rephrase it.

Suppose I have a procedure and want to start it without the client where I start the procedure waiting for it to finish. And I want the procedure to continue even if the client that started it quits.

And I want to be able to check if the procedure is still running.

 

Dirk

 

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