Note: At present, this section is just taken from PostgreSQL documentation and is subject to revision for Postgres-XC.
   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 procedure in the current session.
  
Note: At present, this section is just taken from PostgreSQL documentation and is subject to revision for Postgres-XC.
the prepared statement to be saved
Note: At present, this section is just taken from PostgreSQL documentation and is subject to revision for Postgres-XC.
0 on success; SPI_ERROR_ARGUMENT if plan is NULL or invalid