SPI_finish — disconnect a C function from the SPI manager
int SPI_finish(void)
SPI_finish closes an existing connection to the SPI manager. You must call this function after completing the SPI operations needed during your C function's current invocation. You do not need to worry about making this happen, however, if you abort the transaction via elog(ERROR). In that case SPI will clean itself up automatically.
SPI_OK_FINISHif properly disconnected
SPI_ERROR_UNCONNECTEDif called from an unconnected C function