Description
SPI_connect opens a connection from a procedure
invocation to the SPI manager.
   You must call this function if you will need to execute queries. Some
   utility SPI functions may be called from un-connected procedures.
   If your procedure is already connected,
   SPI_connect will return an
   SPI_ERROR_CONNECT error.  Note that this
   may happen if a procedure which has called
   SPI_connect directly calls another procedure
   which itself calls SPI_connect.  While
   recursive calls to the SPI manager are permitted
   when an SPI query invokes another function which
   uses SPI, directly nested calls to
   SPI_connect and
   SPI_finish are forbidden.