Re: [gnome-db] postgresql provider performance

[Mark Johnson <mrj001 shaw ca>]

Vivien Malerba wrote:
> On Jan 30, 2008 4:04 PM, Mark Johnson <mrj001 shaw ca> wrote:
>   
> > But what information does it provide?  Here is a sample session from psql:
> > issue001_db=# \d+ slots
> >                          Table "public.slots"
> >       Column       |          Type          | Modifiers | Description
> > -------------------+------------------------+-----------+-------------
> >  slot_id           | integer                | not null  |
> >  obj_guid          | character(32)          | not null  |
> >  name              | character varying(500) | not null  |
> >  slot_type         | integer                | not null  |
> >  int64_val         | bigint                 |           |
> >  string_val        | character varying(500) |           |
> >  double_val        | bigint                 |           |
> >  timespec_val      | date                   |           |
> >  guid_val          | character(32)          |           |
> >  numeric_val_num   | bigint                 |           |
> >  numeric_val_denom | bigint                 |           |
> > Indexes:
> >     "slots_pkey" PRIMARY KEY, btree (slot_id)
> > Has OIDs: no
> >
> > issue001_db=# SELECT 1 FROM pg_catalog.pg_class c,
> > pg_catalog.pg_constraint c2, pg_catalog.pg_attribute a WHERE c.relname =
> > 'slots' AND c.oid = c2.conrelid and a.attrelid = c.oid and c2.contype =
> > 'P' and c2.conkey[1] = a.attnum and a.attname = 'slot_id';
> >  ?column?
> > ----------
> > (0 rows)
> >
> > There is not a single row returned by this query.  'slot-id' is the
> > primary key column, which seems to be something this query might be
> > looking for.  Does this possibly behave differently in an older version
> > of PostgreSQL?  I am using 8.2.6.
> >     
>
> I believe the information is in the existence of a row returned or no.
>   
The c2.contype='P' test checks if the column is a primary key.  This 
alternates with checking the columns for a unique key ('u').  However, 
the query is returning zero rows regardless of the presence or absence 
of a primary or unique key.  In the above instance, the column is a 
primary key as shown by the \d+ command.  When I tried columns that are 
not primary keys, they return the same results.  I believe, therefore, 
that there is a problem with this query.
>   
> It's in "V4-branch" branch in the Gnome SVN repository
> (http://svn.gnome.org/viewvc/libgda/branches/V4-branch/).
>
> Tell me of any problem you experience...
>
> Cheers!
>
>   
Thanks, somehow I missed that branch when I did an svn list...

Mark