> I've tried to measure the duration of sql with printing out
> "localtimestamp" but for some reason during the same pg/plsql call
> it returns the same value:
Aram,
From http://www.postgresql.org/docs/current/static/functions-datetime.html:
There is also the function timeofday(), which for historical reasons returns
a text string rather than a timestamp value:
SELECT timeofday();
Result: Sat Feb 17 19:07:32.000126 2001 EST
It is important to know that CURRENT_TIMESTAMP and related functions return
the start time of the current transaction; their values do not change during
the transaction. This is considered a feature: the intent is to allow a
single transaction to have a consistent notion of the "current" time, so that
multiple modifications within the same transaction bear the same time stamp.
timeofday() returns the wall-clock time and does advance during transactions.
-David
