Re: Pulling data from Postgres DB table for every 5 seconds.

> On Jan 9, 2019, at 11:11 AM, github kran <githubkran(at)gmail(dot)com> wrote:
>
> Rob - It's a Java based application. We dont have triggers yet on the table and is trigger a only option in 9.6 version ?.
>
> On Wed, Jan 9, 2019 at 12:01 PM Rob Sargent <robjsargent(at)gmail(dot)com <mailto:robjsargent(at)gmail(dot)com>> wrote:
>
>
> On 1/9/19 10:21 AM, github kran wrote:
>> Thanks for your reply Rob. Reading the below documentation link says the EVENT trigger is only supported for DDL commands. Is it not correct ?.
>>
>> 1) https://www.postgresql.org/docs/9.6/event-trigger-definition.html <https://www.postgresql.org/docs/9.6/event-trigger-definition.html>
>> (An event trigger fires whenever the event with which it is associated occurs in the database in which it is defined. Currently, the only supported events are ddl_command_start, ddl_command_end, table_rewrite and sql_drop. Support for additional events may be added in future releases.).
>> 2) Doesnt the trigger slow down inserts/update we are doing to the table ?. Does it slow down if we are reading the data using the API when we have a trigger in place ?.
>>
>>
> Ah, right you are. Are triggers off the table? You would want to write the trigger function in some (trusted?) language with access to the outside

(Custom here is to “bottom post”)

Have you tried triggers and found them to have too much impact on total system? I can’t see them being more expensive than looking for changes every 5 seconds. If your hardware can scan 1T that quickly then I suspect your trigger will not be noticed. I would have the trigger write to queue and have something else using the queue to talk to IOT piece.

Failing that, perhaps your java (server-side?) app making the changes can be taught to emit the necessary details to IOT-thingy?