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.)