SQL procedures

This adds a new object type "procedure" that is similar to a function
but does not have a return type and is invoked by the new CALL statement
instead of SELECT or similar.  This implementation is aligned with the
SQL standard and compatible with or similar to other SQL implementations.

This commit adds new commands CALL, CREATE/ALTER/DROP PROCEDURE, as well
as ALTER/DROP ROUTINE that can refer to either a function or a
procedure (or an aggregate function, as an extension to SQL).  There is
also support for procedures in various utility commands such as COMMENT
and GRANT, as well as support in pg_dump and psql.  Support for defining
procedures is available in all the languages supplied by the core
distribution.

While this commit is mainly syntax sugar around existing functionality,
future features will rely on having procedures as a separate object
type.

Reviewed-by: Andrew Dunstan <[email protected]>

1 files changed, 11 insertions, 3 deletions

diff --git a/src/pl/plpython/plpy_exec.c b/src/pl/plpython/plpy_exec.c
index fe217c6a2c1..4594a08eadb 100644
--- a/src/pl/plpython/plpy_exec.c
+++ b/src/pl/plpython/plpy_exec.c
@@ -199,12 +199,19 @@ PLy_exec_function(FunctionCallInfo fcinfo, PLyProcedure *proc)
 		error_context_stack = &plerrcontext;
 
 		/*
-		 * If the function is declared to return void, the Python return value
+		 * For a procedure or function declared to return void, the Python return value
 		 * must be None. For void-returning functions, we also treat a None
 		 * return value as a special "void datum" rather than NULL (as is the
 		 * case for non-void-returning functions).
 		 */
-		if (proc->result.typoid == VOIDOID)
+		if (proc->is_procedure)
+		{
+			if (plrv != Py_None)
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("PL/Python procedure did not return None")));
+		}
+		else if (proc->result.typoid == VOIDOID)
 		{
 			if (plrv != Py_None)
 				ereport(ERROR,
@@ -672,7 +679,8 @@ plpython_return_error_callback(void *arg)
 {
 	PLyExecutionContext *exec_ctx = PLy_current_execution_context();
 
-	if (exec_ctx->curr_proc)
+	if (exec_ctx->curr_proc &&
+		!exec_ctx->curr_proc->is_procedure)
 		errcontext("while creating return value");
 }