Re: calling plpgsql from c

Tom Lane wrote:
> Max Jacob  writes:
> > I'm trying to call plpgsql functions from c functions directly through 
> > the Oid, but i have a problem: it seems that the plpgsql interpreter 
> > calls SPI_connect and fails even if the caller has already 
> > spi-connected.
> 
> This is a safety check.  If you are connected to SPI, you need to call
> SPI_push() and SPI_pop() around any operation that might involve
> recursive use of SPI.  That helps delimit "your" calls versus "their"
> calls versus "no man's land".
> 
> It does seem that this is quite undocumented though.  Jan?

I have documented SPI_push() and SPI_pop() with the attached SGML patch.

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073
Index: doc/src/sgml/spi.sgml
===================================================================
RCS file: /cvsroot/pgsql-server/doc/src/sgml/spi.sgml,v
retrieving revision 1.32
diff -c -c -r1.32 spi.sgml
*** doc/src/sgml/spi.sgml	5 Mar 2004 01:00:45 -0000	1.32
--- doc/src/sgml/spi.sgml	17 Mar 2004 01:04:25 -0000
***************
*** 199,204 ****
--- 199,266 ----
  
  
  
+ 
+  
+   SPI_push
+  
+ 
+  
+   SPI_push
+   pushes SPI stack to allow recursive SPI calls
+  
+ 
+  SPI_push
+ 
+  
+ 
+ void SPI_push(void)
+ 
+  
+ 
+  
+   Description
+ 
+   
+    SPI_push pushes a new environment on to the 
+    SPI call stack, allowing recursive calls to use a new environment.
+   
+  
+ 
+ 
+ 
+ 
+ 
+ 
+  
+   SPI_pop
+  
+ 
+  
+   SPI_pop
+   pops SPI stack to allow recursive SPI calls
+  
+ 
+  SPI_pop
+ 
+  
+ 
+ void SPI_pop(void)
+ 
+  
+ 
+  
+   Description
+ 
+   
+    SPI_pop pops the previous environment from the 
+    SPI call stack.  For use when returning from recursive SPI calls.
+   
+  
+ 
+ 
+ 
+ 
+ 
  
   
    SPI_exec
Index: src/backend/executor/spi.c
===================================================================
RCS file: /cvsroot/pgsql-server/src/backend/executor/spi.c,v
retrieving revision 1.110
diff -c -c -r1.110 spi.c
*** src/backend/executor/spi.c	5 Mar 2004 00:47:01 -0000	1.110
--- src/backend/executor/spi.c	17 Mar 2004 01:04:27 -0000
***************
*** 201,212 ****
--- 201,214 ----
  	SPI_tuptable = NULL;
  }
  
+ /* Pushes SPI stack to allow recursive SPI calls */
  void
  SPI_push(void)
  {
  	_SPI_curid++;
  }
  
+ /* Pops SPI stack to allow recursive SPI calls */
  void
  SPI_pop(void)
  {
Index: src/include/executor/spi.h
===================================================================
RCS file: /cvsroot/pgsql-server/src/include/executor/spi.h,v
retrieving revision 1.42
diff -c -c -r1.42 spi.h
*** src/include/executor/spi.h	5 Mar 2004 00:47:01 -0000	1.42
--- src/include/executor/spi.h	17 Mar 2004 01:04:28 -0000
***************
*** 81,88 ****
  extern int	SPI_finish(void);
  extern void SPI_push(void);
  extern void SPI_pop(void);
! extern int	SPI_exec(const char *src, int tcount);
! extern int SPI_execp(void *plan, Datum *values, const char *Nulls,
  		  int tcount);
  extern int SPI_execp_current(void *plan, Datum *values, const char *Nulls,
  							 bool useCurrentSnapshot, int tcount);
--- 81,88 ----
  extern int	SPI_finish(void);
  extern void SPI_push(void);
  extern void SPI_pop(void);
! extern int  SPI_exec(const char *src, int tcount);
! extern int  SPI_execp(void *plan, Datum *values, const char *Nulls,
  		  int tcount);
  extern int SPI_execp_current(void *plan, Datum *values, const char *Nulls,
  							 bool useCurrentSnapshot, int tcount);