Re: [gnome-db] 2 issues with GdaConnection

[Mark Johnson <mrj001 shaw ca>]

Vivien Malerba wrote:
> On Fri, Mar 21, 2008 at 4:44 PM, Mark Johnson <mrj001 shaw ca> wrote:
>   
> > On page:
> >  http://library.gnome.org/devel/libgda-4.0/3.99/GdaConnection.html
> >  for function gda_connection_open_from_dsn, we find:
> >  " If a new GdaConnection
> >  <http://library.gnome.org/devel/libgda-4.0/3.99/GdaConnection.html> is
> >  created, then the caller will hold a reference on it."
> >  This seems to imply that if an existing connection was returned from a
> >  pool of connections, then the caller does not hold a reference on it.
> >  Therefore, the caller should call g_object_unref only in the case when a
> >  new connection is created.
> >  Question: How does one tell if a new connection was created?
> >
> >  On page:
> >  http://library.gnome.org/devel/libgda-4.0/3.99/connections.html
> >  We find this statement:
> >  " Closing the connection can be ordered using gda_connection_close ()
> >  <http://library.gnome.org/devel/libgda-4.0/3.99/GdaConnection.html#gda-connection-close>,
> >  or is automatically done when the connection object is destroyed (as is
> >  the case in the example abive when g_object_unref() is called with the
> >  connection as argument)."
> >     
>
> That was from the V3 version where there wer connection pools
> (GdaClient object). Now a GdaConnection object is created everytime
> gda_connection_open_from...() is called sucessfully. I'll correct the
> doc.
>   
Thanks.
>   
> >  When I called g_object_unref on the connection, expecting it to close
> >  automatically, I found the following in the PostgreSQL log:
> >  issue513149_dbLOG:  unexpected EOF on client connection
> >  issue513149_dbLOG:  disconnection: session time: 0:00:00.268
> >  user=issue513149_user database=issue513149_db host=127.0.0.1 port=37580
> >
> >  When I added a call to gda_connection_close prior to the g_object_unref,
> >  the unexpected EOF message did not appear.  It seems that with
> >  PostgreSQL, the connection is not automatically closing.
> >     
>
> Closing the connection is done automatically when a connection object
> is destroted (the same provider's function is called). Are you sure
> you did not have 2 references on the connection before calling
> g_object_unref()? Otherwise can you send me the piece of code (I'm a
> bit lazy...)?
>   
I don't think I have 2 references to the connection.  I've attached a 
current snapshot of my file to let you see it.  It's a work in progress 
for a test case for one of my bugs.
> Thanks,
>
> Vivien
Mark


#include <libgda/libgda.h>
#include <sql-parser/gda-sql-parser.h>
#define TABLE_NAME "slots"

int main()
{
GdaClient *pClient = NULL;
GdaConnection *pConn = NULL;
GError *error = NULL;
GdaSqlParser *pParser = NULL;
GdaStatement *pStmt = NULL;
GdaSet *pParams = NULL;
GdaHolder *pHolder = NULL;
gchar* field_name = NULL;
GValue *pValue = NULL;
 
printf("Initializing\n");
g_type_init();
gda_init("Issue513149", "1.0", 0, NULL);

// Connect to the server
printf("Connecting\n");
pConn = gda_connection_open_from_dsn("Issue513149",
         NULL,                       // auth string
         GDA_CONNECTION_OPTIONS_NONE,
         &error);
if (error != NULL)
   {
   fprintf(stderr, "Error calling gda_connection_open_from_dsn\n");
   fprintf(stderr, error->message);
   exit(1);
   }

// Create the SQL statement object
printf("building statement\n");
pParser = gda_sql_parser_new();
pStmt = gda_sql_parser_parse_string(pParser,
         "SELECT * FROM slots WHERE obj_guid = ##the_guid::string",
         NULL,
         &error);
if (error != NULL)
   {
   fprintf(stderr, "Error calling gda_sql_parser_parse_string\n");
   fprintf(stderr, error->message);
   exit(1);
   }
g_object_unref(pParser);
pParser = NULL;

gda_statement_get_parameters(pStmt, &pParams, &error);
if (error != NULL)
   {
   fprintf(stderr, "Error calling gda_statement_get_parameters\n");
   fprintf(stderr, error->message);
   exit(1);
   }
pHolder = gda_set_get_holder(pParams, "the_guid");
if (pHolder == NULL)
   {
   fprintf(stderr, "Error calling gda_set_get_holder\n");
   exit(1);
   }
pValue = gda_value_new(G_TYPE_STRING);
g_value_set_string(pValue, "4cbf958a005bee408d13aef08914e1c9");
gda_holder_set_value(pHolder, pValue);

// execute query
printf("executing query\n");
// printf("QUERY: %s\n", gda_connection_statement_to_sql(pConn,
//          pStmt,
//          pParams,
//          );
gda_connection_statement_execute_select(pConn, pStmt, pParams, &error);
if (error != NULL)
   {
   fprintf(stderr, "Error calling gda_connection_statement_execute_select\n");
   fprintf(stderr, error->message);
   exit(1);
   }
  
   g_object_unref(pParams);
   pParams = NULL;
   g_object_unref(pStmt);
   pStmt = NULL;

   // close connection
   gda_connection_close(pConn);
   g_object_unref(pConn);
   pConn = NULL;
}