int SPI_keepplan(SPIPlanPtr plan)
SPI_keepplan saves a passed statement (prepared by SPI_prepare) so that it will not be freed by SPI_finish nor by the transaction manager. This gives you the ability to reuse prepared statements in the subsequent invocations of your C function in the current session.
the prepared statement to be saved
0 on success; SPI_ERROR_ARGUMENT if plan is NULL or invalid
The passed-in statement is relocated to permanent storage by means of pointer adjustment (no data copying is required). If you later wish to delete it, use SPI_freeplan on it.