SPI_connect
Description
  
   SPI_connect
  
  opens a connection from a
   procedure invocation to the SPI manager.  You must call this
   function if you want to execute commands through SPI.  Some utility
   SPI functions can be called from unconnected procedures.
 
  If your procedure is already connected,
  
   SPI_connect
  
  will return the error code
  
   SPI_ERROR_CONNECT
  
  .  This could happen if
   a procedure that has called
  
   SPI_connect
  
  directly calls another procedure that calls
  
   SPI_connect
  
  .  While recursive calls to the
  
   SPI
  
  manager are permitted when an SQL command
   called through SPI invokes another function that uses
  
   SPI
  
  , directly nested calls to
  
   SPI_connect
  
  and
  
   SPI_finish
  
  are forbidden.
   (But see
  
   SPI_push
  
  and
  
   SPI_pop
  
  .)