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Improve the recently-added code for inlining set-returning functions so that 

it can handle functions returning setof record.  The case was left undone
originally, but it turns out to be simple to fix.
This commit is contained in:
Tom Lane 2008-10-09 19:27:40 +00:00
parent cbe99a97a8
commit 76e6602417
3 changed files with 70 additions and 17 deletions
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4
src/backend/optimizer/prep/prepjointree.c
View File

@ -16,7 +16,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/prep/prepjointree.c,v 1.55 2008/10/04 21:56:53 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/prep/prepjointree.c,v 1.56 2008/10/09 19:27:40 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -383,7 +383,7 @@ inline_set_returning_functions(PlannerInfo *root)
Query *funcquery;
/* Check safety of expansion, and expand if possible */
funcquery = inline_set_returning_function(root, rte->funcexpr);
funcquery = inline_set_returning_function(root, rte);
if (funcquery)
{
/* Successful expansion, replace the rtable entry */

78
src/backend/optimizer/util/clauses.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.268 2008/10/04 21:56:53 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.269 2008/10/09 19:27:40 tgl Exp $
*
* HISTORY
* AUTHOR DATE MAJOR EVENT
@ -111,6 +111,7 @@ static Query *substitute_actual_srf_parameters(Query *expr,
int nargs, List *args);
static Node *substitute_actual_srf_parameters_mutator(Node *node,
substitute_actual_srf_parameters_context *context);
static bool tlist_matches_coltypelist(List *tlist, List *coltypelist);
/*****************************************************************************
@ -3659,17 +3660,16 @@ evaluate_expr(Expr *expr, Oid result_type, int32 result_typmod)
* inline_set_returning_function
* Attempt to "inline" a set-returning function in the FROM clause.
*
* "node" is the expression from an RTE_FUNCTION rangetable entry. If it
* represents a call of a set-returning SQL function that can safely be
* inlined, expand the function and return the substitute Query structure.
* Otherwise, return NULL.
* "rte" is an RTE_FUNCTION rangetable entry. If it represents a call of a
* set-returning SQL function that can safely be inlined, expand the function
* and return the substitute Query structure. Otherwise, return NULL.
*
* This has a good deal of similarity to inline_function(), but that's
* for the non-set-returning case, and there are enough differences to
* justify separate functions.
*/
Query *
inline_set_returning_function(PlannerInfo *root, Node *node)
inline_set_returning_function(PlannerInfo *root, RangeTblEntry *rte)
{
FuncExpr *fexpr;
HeapTuple func_tuple;
@ -3686,6 +3686,8 @@ inline_set_returning_function(PlannerInfo *root, Node *node)
Query *querytree;
int i;
Assert(rte->rtekind == RTE_FUNCTION);
/*
* It doesn't make a lot of sense for a SQL SRF to refer to itself
* in its own FROM clause, since that must cause infinite recursion
@ -3695,9 +3697,9 @@ inline_set_returning_function(PlannerInfo *root, Node *node)
check_stack_depth();
/* Fail if FROM item isn't a simple FuncExpr */
if (node == NULL || !IsA(node, FuncExpr))
fexpr = (FuncExpr *) rte->funcexpr;
if (fexpr == NULL || !IsA(fexpr, FuncExpr))
return NULL;
fexpr = (FuncExpr *) node;
/*
* The function must be declared to return a set, else inlining would
@ -3707,10 +3709,6 @@ inline_set_returning_function(PlannerInfo *root, Node *node)
if (!fexpr->funcretset)
return NULL;
/* Fail if function returns RECORD ... we don't have enough context */
if (fexpr->funcresulttype == RECORDOID)
return NULL;
/*
* Refuse to inline if the arguments contain any volatile functions or
* sub-selects. Volatile functions are rejected because inlining may
@ -3837,9 +3835,20 @@ inline_set_returning_function(PlannerInfo *root, Node *node)
if (!check_sql_fn_retval(fexpr->funcid, fexpr->funcresulttype,
querytree_list,
true, NULL) &&
get_typtype(fexpr->funcresulttype) == TYPTYPE_COMPOSITE)
(get_typtype(fexpr->funcresulttype) == TYPTYPE_COMPOSITE ||
fexpr->funcresulttype == RECORDOID))
goto fail; /* reject not-whole-tuple-result cases */
/*
* If it returns RECORD, we have to check against the column type list
* provided in the RTE; check_sql_fn_retval can't do that. (If no match,
* we just fail to inline, rather than complaining; see notes for
* tlist_matches_coltypelist.)
*/
if (fexpr->funcresulttype == RECORDOID &&
!tlist_matches_coltypelist(querytree->targetList, rte->funccoltypes))
goto fail;
/*
* Looks good --- substitute parameters into the query.
*/
@ -3938,3 +3947,46 @@ substitute_actual_srf_parameters_mutator(Node *node,
substitute_actual_srf_parameters_mutator,
(void *) context);
}
/*
* Check whether a SELECT targetlist emits the specified column types,
* to see if it's safe to inline a function returning record.
*
* We insist on exact match here. The executor allows binary-coercible
* cases too, but we don't have a way to preserve the correct column types
* in the correct places if we inline the function in such a case.
*
* Note that we only check type OIDs not typmods; this agrees with what the
* executor would do at runtime, and attributing a specific typmod to a
* function result is largely wishful thinking anyway.
*/
static bool
tlist_matches_coltypelist(List *tlist, List *coltypelist)
{
ListCell *tlistitem;
ListCell *clistitem;
clistitem = list_head(coltypelist);
foreach(tlistitem, tlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(tlistitem);
Oid coltype;
if (tle->resjunk)
continue; /* ignore junk columns */
if (clistitem == NULL)
return false; /* too many tlist items */
coltype = lfirst_oid(clistitem);
clistitem = lnext(clistitem);
if (exprType((Node *) tle->expr) != coltype)
return false; /* column type mismatch */
}
if (clistitem != NULL)
return false; /* too few tlist items */
return true;
}

5
src/include/optimizer/clauses.h
View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/optimizer/clauses.h,v 1.94 2008/08/25 22:42:34 tgl Exp $
* $PostgreSQL: pgsql/src/include/optimizer/clauses.h,v 1.95 2008/10/09 19:27:40 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -77,6 +77,7 @@ extern Node *eval_const_expressions(PlannerInfo *root, Node *node);
extern Node *estimate_expression_value(PlannerInfo *root, Node *node);
extern Query *inline_set_returning_function(PlannerInfo *root, Node *node);
extern Query *inline_set_returning_function(PlannerInfo *root,
RangeTblEntry *rte);
#endif /* CLAUSES_H */