I'm making my first steps in C functions. I want to avoid doing all the SQL job in them, pl/pgsql looks a better choice. I tried to do this by passing opened cursor from pl/pgsql function to C function.
Here is simple C function:
#include <server/postgres.h>
#include <server/executor/spi.h>
PG_FUNCTION_INFO_V1(test2);
Datum test2(PG_FUNCTION_ARGS)
{
Portal p;
int n;
p=SPI_cursor_find("xxx");
if(!p)
elog(ERROR,"Cursor error");
SPI_cursor_fetch(p,true,1);
n=SPI_processed;
PG_RETURN_INT32(n);
}And pl/pgsql one: CREATE OR REPLACE FUNCTION test() returns integer AS ' DECLARE _m CURSOR FOR select id from some_table limit 1; n integer; BEGIN _m=''xxx''; open _m; n=test2(); close _m; return n; END; ' language 'plpgsql';
select test(); I don't understand ERROR message at all: ERROR: SPI_prepare() failed on "SELECT $1 "
This error is raised when trying to execute SPI_cursor_fetch. What does it mean? What does the SPI_prepare have to already opened cursor?
Where can I find better SPI documentation than "Postgresql Server Programming" ?
Regards, Tomasz Myrta
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