SPI_saveplan stores a plan
prepared by SPI_prepare in safe
memory protected from freeing by SPI_finish or the transaction manager.
In the current version of PostgreSQL there is no ability to store
prepared plans in the system catalog and fetch them from there
for execution. This will be implemented in future versions. As an
alternative, there is the ability to reuse prepared plans in the
subsequent invocations of your procedure in the current session.
Use SPI_execp to execute this saved
plan.
SPI_saveplan saves a passed plan
(prepared by SPI_prepare) in memory
protected from freeing by SPI_finish and by the transaction manager and
returns a pointer to the saved plan. You may save the pointer
returned in a local variable. Always check if this pointer is
NULL or not either when preparing a plan or using an already
prepared plan in SPI_execp (see below).
Note: If one of the objects (a relation, function, etc.) referenced by the prepared plan is dropped during your session (by your backend or another process) then the results of
SPI_execpfor this plan will be unpredictable.