Message-ID: <542DD92A.9000305@comcast.net>
Date: Thu, 02 Oct 2014 19:00:58 -0400
From: George Neuner <gneuner2@comcast.net>
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To: pgsql-performance@postgresql.org
Subject: help: function failing
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Hi,

I am using Postgresql 9.3.5 on Ubuntu and I have a sudden, unexplained 
failure in a function that has been working for a long time.

--------------- 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);

If I comment out that line, it then tells me  get_byte()   is undefined, 
which should be impossible because it's built in.


This gen_random() function is in public, the pgcrypto function 
gen_random_bytes() is in a separate utility schema "ext".  This is in a 
test database which I am in process of modifying, but it works perfectly 
when dumped and restored to a different computer.  This gen_random()  
function - and its environment - has been working in multiple systems 
for quite a while.

I suspect that the Postgresql installation somehow has been hosed and 
that I'm looking at a reinstall, but I have no idea how I managed it.  
I'd like to know what happened so I can (try to) avoid it going 
forward.  There haven't been any recent system updates, and AFAIK there 
haven't been any crashes either.  Occasionally pgAdmin3 does hang up, 
but that happens very infrequently and has occurred on all the working 
systems as well.  I have been adding new tables and functions to the 
public schema on this test system, but I haven't touched anything that 
was already working.

It seems like Postgresql just snapped.  Any ideas?  Anything in 
particular I might look at for a clue?

Thanks,
George


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