Thread

1. Full bug list

   Andy Marden <amarden@usa.net> — 2002-02-21T09:32:55Z

   Is there a repository on the web somewhere of all the bugs found, versions
   they are found against and what theire status is?
   
   
   
   

2. Re: Full bug list

   Justin Clift <aa2@bigpond.net.au> — 2002-02-22T03:24:22Z

   Hi Andy,
   
   Thats the reason which techdocs.postgresql.org started for, but since it's 
   grown to encompass so many things, that section hasn't been updated in ages.  
   :-(
   
   Perhaps its time to look at a better way of keeping it updated?
   
   :-)
   
   Regards and best wishes,
   
   Justin Clift
   
   On Thursday 21 February 2002 20:32, Andy Marden wrote:
   > Is there a repository on the web somewhere of all the bugs found, versions
   > they are found against and what theire status is?
   >
   >
   >
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3. my pl/pgsql functions return weird results

   Olivier Garcia <ogarcia@waidan.com> — 2002-02-22T08:07:28Z

   Hi!
   
   My base contains a table objectid
   
   create table objectid(
   	next bigint
   );
   
   INSERT INTO objectid values(1);
   
   I do really need to use this table like if it was a sequence so I made
   some pl/pgsql functions ( functions at the end of the mail ).
   But when I run them in three psql at the same time the results are
   weird... Here are the results :
   
   psql1: 2 ( ok )
   psql2: 1 ( instead of 3 )
   psql3: 1 ( instead of 4 )
   
   Scary...
   
   and after that, a "select * from objectid;" returns 4 ( that's ok ). 
   
   I'm using pgsql 7.1.3 ( debian package 7.1.3-8 on a 2.4.17 kernel ) 
   
   -----------------------------
   ----------- Functions
   -----------------------------
   
   drop table objectid;
   
   create table objectid(
   	next bigint
   );
   
   INSERT INTO objectid values(1);
   
   drop function next_objectid();
    
   create function next_objectid() returns bigint as '
   DECLARE
      o RECORD;
      a integer;
   BEGIN
      raise notice ''before lock'';
      lock table objectid in access exclusive mode;
      raise notice ''locked, before pause'';
      a := pause(1000000);
      raise notice ''pause finished, updating'';
      update objectid set next=next+1;
      select into o next from objectid; 
      raise notice ''returning'';
      return o.next;
   END;
   ' language 'plpgsql';
    
   drop function pause(int);
    
   create function pause(int) returns int as '
   DECLARE
      i integer;
      j integer;
   BEGIN
      FOR i IN 1 .. $1 LOOP
         j := i+1;
      end loop;
      return j;
   END;
   ' language 'plpgsql';
   
   
   
   
   
   

4. Re: my pl/pgsql functions return weird results

   Tom Lane <tgl@sss.pgh.pa.us> — 2002-02-22T15:10:53Z

   Olivier Garcia <ogarcia@waidan.com> writes:
   > [ can't re-implement nextval() in plpgsql ]
   
   The problem is that plpgsql doesn't do SetQuerySnapshot between
   statements of a function, so although your different invocations are
   forced to wait for each other by the LOCK statements, they cannot see
   each other's effects on the objectid table.  (Each one sees the others
   as transactions that hadn't committed when it started, so it ignores
   their effects per MVCC rules.)
   
   Whether this is a bug, and if so what correct behavior ought to be,
   has been the subject of some dispute for awhile --- try searching in
   the pghackers archives for "CommandCounterIncrement" and
   "SetQuerySnapshot".  Nothing's been decided yet.
   
   Although you could get the behavior you want by issuing the commands
   separately (not bundled in a plpgsql function), I rather wonder why
   you are going to all this effort.  Why not just use a sequence?
   
   			regards, tom lane