Re: Linear slow-down while inserting into a table with an ON INSERT trigger ?

David Rowley <dgrowleyml(at)gmail(dot)com> writes:
> On Sat, 17 Jul 2021 at 16:40, Justin Pryzby <pryzby(at)telsasoft(dot)com> wrote:
>> You could run a single UPDATE rather than 30k triggers.
>> Or switch to an INSERT on the table, with an index on it, and call
>> max(last_parent_table_change) from whatever needs to ingest it. And prune the
>> old entries and vacuum it outside the transaction. Maybe someone else will
>> have a better suggestion.

> Maybe just change the UPDATE statement to:
> UPDATE data_sync SET last_parent_table_change=CURRENT_TIMESTAMP WHERE
> last_parent_table_change <> CURRENT_TIMESTAMP;
> That should reduce the number of actual updates to 1 per transaction.

Or, if it's impractical to make the application do that for itself,
this could be a job for suppress_redundant_updates_trigger().

https://www.postgresql.org/docs/current/functions-trigger.html

regards, tom lane