How to improve PgSql Performance using npgsql

Dear All,

I am using npgsql.dll to connect postgresql database. Everything is
working fine.but sometimes database is getting slow and even sometimes I am
not getting data .I have written one function which access the data .

Below is my code ..

public NpgsqlConnection PgSqlDataConnection()

{

if (pgSqlConnection != null)

{

if (pgSqlConnection.State == ConnectionState.Open)

{

pgSqlConnection.Close();

//pgSqlConnection.Dispose();

}

}

pgConnectionString =
ConfigurationSettings.AppSettings["ConnectionString"].ToString();

pgSqlConnection = new NpgsqlConnection(pgConnectionString);

try

{

pgSqlConnection.Open();

}

catch (Exception exp)

{}

return pgSqlConnection;

}

Please let me where I am doing wrong.

I am waiting for your great response.

Advanced thanks.

Reagrds,

Venkat.