SPI_pfree — free memory in the upper executor context
void SPI_pfree(void * pointer)   SPI_pfree frees memory previously allocated
   using SPI_palloc or
   SPI_repalloc.
  
   This function is no longer different from plain
   pfree.  It's kept just for backward
   compatibility of existing code.
  
void * pointerpointer to existing storage to free