On 10/07/2014 04:41 PM, Sergey Konoplev wrote:
On Thu, Oct 2, 2014 at 4:00 PM, George Neuner <gneuner2@xxxxxxxxxxx> wrote:
--------------- code ----------------
CREATE OR REPLACE FUNCTION gen_random()
RETURNS double precision AS
$BODY$
DECLARE
num float8 := 0;
den float8 := 281474976710655; -- 0xFFFFFFFFFFFF
bytes bytea[6];
BEGIN
-- get random bytes from crypto module
bytes := ext.gen_random_bytes(6);
-- assemble a double precision value
num := num + get_byte( bytes, 0 );
FOR i IN 1..5 LOOP
num := num * 256;
num := num + get_byte( bytes, i );
END LOOP;
-- normalize value to range 0.0 .. 1.0
RETURN num / den;
END;
$BODY$
LANGUAGE plpgsql VOLATILE;
--------------- code ----------------
The error is:
ERROR: array value must start with "{" or dimension information
SQL state: 22P02
Context: PL/pgSQL function gen_random() line 8 at assignment
which, if I'm counting correctly, is
bytes := ext.gen_random_bytes(6);
Guessing on the name of ext.gen_random_bytes(6) it returns a value
that is incompatible with bytea[] array representation time from time,
so take a closer look at ext.gen_random_bytes() first. You can test
the case using DO block.
If I comment out that line, it then tells me get_byte() is undefined,
which should be impossible because it's built in.
Feels like somewhere inside ext.gen_random_bytes() you set a
search_path that allows to see get_byte() and the search_path that was
set before the gen_random() call doesn't allow it.
Why does this code want an array of byteas?
It looks like the code thinks bytea[6] is a declaration of a bytea of
length 6, which of course it is not. Shouldn't it just be declared as:
bytes bytea;
?
Oh, and pgsql-performance is completely the wrong forum for this query.
usage questions should be on pgsql-general.
cheers
andrew
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