Hi

>> >> The test performs about 11K lines of code
>> >> Oracle: about 5M
>> >> postgreSql: about 160М


>What is the actual O/S that PostgreSQL is installed on? 
>How much total memory is on the server? 
>I would be very curious about the values you have  specified in postgresql.conf?
> Also, what is the exact version of PostgreSQL you are using?
>What is the total time to complete the test for all 3 DB's?
>The best I can tell is that with all the unknowns, you are comparing apples to oranges.

There is real problem for us.
The PL/pgSQL interpreter parses the function's source text and produces an internal binary instruction tree the first time the function is called (within each session) 

The size of this instruction tree depends only of postgreSql build.

And size is big, and size is not share between session.

I understand that nobody says: Damn One second I will implement it soon :)

Thank all for constructive answers.