Re: function for setting/getting same timestamp during whole transaction

>
> probably you can use a little bit cheaper session variables
>

I rejected session variables, because they don't get cleared at the end of
transaction if somebody set value on session level. So I can't decide if
new transaction started.

this is good (variable is cleared at the end of transaction):
begin;
set local test.value to 123;
show test.value;
test.value
------------
123
commit;
show test.value; --cleared => transaction ended
test.haha
-----------

but this is bad:
begin;
set local test.value to 123;
show test.value;
test.value
------------
123
set test.value to 456;
commit;
show test.value; --not cleared
test.haha
-----------
456

> test to system tables is slower then trapping error - just try to read
> from tmp and when a read fails, then create table
>

Ok I will try reading from temp table directly with error trapping and
compare times.

> probably C trigger can be very effective, possible to use this
> technique - http://postgres.cz/wiki/Funkce_rownum%28%29 (sorry, it is
> in Czech language)
>

I'm from Slovakia so I don't have problem with czech language, but I'm not
sure how to do it in C function without using temp table, because I need to
clear variable at the end/start of transaction. Any hints?

Miro