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Mop-up for letting VOID-returning SQL functions end with a SELECT.

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Part of the intent in commit fd1a421fe was to allow SQL functions that are
declared to return VOID to contain anything, including an unrelated final
SELECT, the same as SQL-language procedures can.  However, the planner's
inlining logic didn't get that memo.  Fix it, and add some regression tests
covering this area, since evidently we had none.

In passing, clean up some typos in comments in create_function_3.sql,
and get rid of its none-too-safe assumption that DROP CASCADE notice
output is immutably ordered.

Per report from Prabhat Sahu.

Discussion: https://postgr.es/m/CANEvxPqxAj6nNHVcaXxpTeEFPmh24Whu+23emgjiuKrhJSct0A@mail.gmail.com
This commit is contained in:
Tom Lane
2018-03-16 12:48:13 -04:00
parent 84a3611ccc
commit 877cdf11ea
3 changed files with 130 additions and 33 deletions
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25
src/backend/optimizer/util/clauses.c
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@@ -4487,8 +4487,8 @@ inline_function(Oid funcid, Oid result_type, Oid result_collid,
* properties. (The prokind and nargs checks are just paranoia.)
*/
if (funcform->prolang != SQLlanguageId ||
funcform->prosecdef ||
funcform->prokind != PROKIND_FUNCTION ||
funcform->prosecdef ||
funcform->proretset ||
funcform->prorettype == RECORDOID ||
!heap_attisnull(func_tuple, Anum_pg_proc_proconfig) ||
@@ -4623,9 +4623,18 @@ inline_function(Oid funcid, Oid result_type, Oid result_collid,
/* Now we can grab the tlist expression */
newexpr = (Node *) ((TargetEntry *) linitial(querytree->targetList))->expr;
/* Assert that check_sql_fn_retval did the right thing */
Assert(exprType(newexpr) == result_type);
/* It couldn't have made any dangerous tlist changes, either */
/*
* If the SQL function returns VOID, we can only inline it if it is a
* SELECT of an expression returning VOID (ie, it's just a redirection to
* another VOID-returning function). In all non-VOID-returning cases,
* check_sql_fn_retval should ensure that newexpr returns the function's
* declared result type, so this test shouldn't fail otherwise; but we may
* as well cope gracefully if it does.
*/
if (exprType(newexpr) != result_type)
goto fail;
/* check_sql_fn_retval couldn't have made any dangerous tlist changes */
Assert(!modifyTargetList);
/*
@@ -5010,12 +5019,16 @@ inline_set_returning_function(PlannerInfo *root, RangeTblEntry *rte)
* properties. In particular it mustn't be declared STRICT, since we
* couldn't enforce that. It also mustn't be VOLATILE, because that is
* supposed to cause it to be executed with its own snapshot, rather than
* sharing the snapshot of the calling query. (Rechecking proretset is
* just paranoia.)
* sharing the snapshot of the calling query. We also disallow returning
* SETOF VOID, because inlining would result in exposing the actual result
* of the function's last SELECT, which should not happen in that case.
* (Rechecking prokind and proretset is just paranoia.)
*/
if (funcform->prolang != SQLlanguageId ||
funcform->prokind != PROKIND_FUNCTION ||
funcform->proisstrict ||
funcform->provolatile == PROVOLATILE_VOLATILE ||
funcform->prorettype == VOIDOID ||
funcform->prosecdef ||
!funcform->proretset ||
!heap_attisnull(func_tuple, Anum_pg_proc_proconfig))