detailed timing of operation in postgres

Question

suppose i have some triggers on some table ON Insert. How can i know what time it actually takes to insert and what time it takes to execute trigger ?

Answer 1

If you use explain (analyze, verbose) for the statement that fires the trigger you will see the execution time of each trigger on the table.

So if you have a table foo with a trigger, and run something like this:

explain (analyze, verbose)
insert into foo (id) 
values (1);

You'll get an output similar to this:

Insert on foo (cost=0.00..0.01 rows=1 width=0) (actual time=938.776..938.776 rows=0 loops=1)
  ->  Result  (cost=0.00..0.01 rows=1 width=0) (actual time=0.014..0.014 rows=1 loops=1)
        Output: 1
Planning time: 0.040 ms
Trigger foo_trg: time=937.371 calls=1 <<<< here
Execution time: 938.802 ms

Note that explain (analyze) will in fact run that statement. So the new row will be inserted. You need to rollback if you don't want that.