Postgresql定义C函数直接调试内核

#include "postgres.h"
#include "fmgr.h"
#include "access/xact.h"
#include "access/transam.h"
#include "access/xlog.h"
#include "storage/proc.h"


PG_MODULE_MAGIC;

PG_FUNCTION_INFO_V1(showproc);

Datum
showproc(PG_FUNCTION_ARGS)
{
        elog(ERROR, "MyProc->pid: %d, MyProc->pgprocno: %d", MyProc->pid, MyProc->pgprocno);
        PG_RETURN_VOID();
}

gcc -O3 -Wall -Wextra -I /home/mingjiegao/dev/src/postgresql-10.17/src/include -g -fPIC -c ./showproc.c -o showproc.o   

gcc -O3 -Wall -Wextra -I /home/mingjiegao/dev/src/postgresql-10.17/src/include -g -shared showproc.o -o libshowproc.so  

create or replace function showproc() returns int8 as '/home/mingjiegao/extentions/showproc/libshowproc.so', 'showproc' language C STRICT;  

postgres=# select showproc();
ERROR:  MyProc->pid: 28780, MyProc->pgprocno: 97