code: func PgExtensionByExtname(db XODB, extname pgtypes.Name) (*PgExtension, error) {
  	var err error
  
  	// sql query
  	const sqlstr = `SELECT ` +
  		`tableoid, cmax, xmax, cmin, xmin, oid, ctid, extname, extowner, extnamespace, extrelocatable, extversion, extconfig, extcondition ` +
  		`FROM pg_catalog.pg_extension ` +
  		`WHERE extname = $1`
  
  	// run query
  	XOLog(sqlstr, extname)
  	pe := PgExtension{}
  
  	err = db.QueryRow(sqlstr, extname).Scan(&pe.Tableoid, &pe.Cmax, &pe.Xmax, &pe.Cmin, &pe.Xmin, &pe.Oid, &pe.Ctid, &pe.Extname, &pe.Extowner, &pe.Extnamespace, &pe.Extrelocatable, &pe.Extversion, &pe.Extconfig, &pe.Extcondition)
  	if err != nil {
  		return nil, err
  	}
  
  	return &pe, nil
  }
docs: // PgExtensionByExtname retrieves a row from 'pg_catalog.pg_extension' as a PgExtension.
  //
  // Generated from index 'pg_extension_name_index'.