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Improve the handling of result type coercions in SQL functions.

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Use the parser's standard type coercion machinery to convert the
output column(s) of a SQL function's final SELECT or RETURNING
to the type(s) they should have according to the function's declared
result type.  We'll allow any case where an assignment-level
coercion is available.  Previously, we failed unless the required
coercion was a binary-compatible one (and the documentation ignored
this, falsely claiming that the types must match exactly).

Notably, the coercion now accounts for typmods, so that cases where
a SQL function is declared to return a composite type whose columns
are typmod-constrained now behave as one would expect.  Arguably
this aspect is a bug fix, but the overall behavioral change here
seems too large to consider back-patching.

A nice side-effect is that functions can now be inlined in a
few cases where we previously failed to do so because of type
mismatches.

Discussion: https://postgr.es/m/18929.1574895430@sss.pgh.pa.us
This commit is contained in:
Tom Lane
2020-01-08 11:07:53 -05:00
parent 8dd1511e39
commit 913bbd88dc
7 changed files with 656 additions and 332 deletions
Download Patch File Download Diff File Expand all files Collapse all files

11
src/backend/catalog/pg_proc.c
View File

@ -923,6 +923,8 @@ fmgr_sql_validator(PG_FUNCTION_ARGS)
* verify the result type.
*/
SQLFunctionParseInfoPtr pinfo;
Oid rettype;
TupleDesc rettupdesc;
/* But first, set up parameter information */
pinfo = prepare_sql_fn_parse_info(tuple, NULL, InvalidOid);
@ -943,9 +945,12 @@ fmgr_sql_validator(PG_FUNCTION_ARGS)
}
check_sql_fn_statements(querytree_list);
(void) check_sql_fn_retval(funcoid, proc->prorettype,
querytree_list,
NULL, NULL);
(void) get_func_result_type(funcoid, &rettype, &rettupdesc);
(void) check_sql_fn_retval(querytree_list,
rettype, rettupdesc,
false, NULL);
}
error_context_stack = sqlerrcontext.previous;

508
src/backend/executor/functions.c
View File

@ -154,7 +154,7 @@ static Node *sql_fn_resolve_param_name(SQLFunctionParseInfoPtr pinfo,
static List *init_execution_state(List *queryTree_list,
SQLFunctionCachePtr fcache,
bool lazyEvalOK);
static void init_sql_fcache(FmgrInfo *finfo, Oid collation, bool lazyEvalOK);
static void init_sql_fcache(FunctionCallInfo fcinfo, Oid collation, bool lazyEvalOK);
static void postquel_start(execution_state *es, SQLFunctionCachePtr fcache);
static bool postquel_getnext(execution_state *es, SQLFunctionCachePtr fcache);
static void postquel_end(execution_state *es);
@ -166,6 +166,11 @@ static Datum postquel_get_single_result(TupleTableSlot *slot,
MemoryContext resultcontext);
static void sql_exec_error_callback(void *arg);
static void ShutdownSQLFunction(Datum arg);
static bool coerce_fn_result_column(TargetEntry *src_tle,
Oid res_type, int32 res_typmod,
bool tlist_is_modifiable,
List **upper_tlist,
bool *upper_tlist_nontrivial);
static void sqlfunction_startup(DestReceiver *self, int operation, TupleDesc typeinfo);
static bool sqlfunction_receive(TupleTableSlot *slot, DestReceiver *self);
static void sqlfunction_shutdown(DestReceiver *self);
@ -591,18 +596,21 @@ init_execution_state(List *queryTree_list,
* Initialize the SQLFunctionCache for a SQL function
*/
static void
init_sql_fcache(FmgrInfo *finfo, Oid collation, bool lazyEvalOK)
init_sql_fcache(FunctionCallInfo fcinfo, Oid collation, bool lazyEvalOK)
{
FmgrInfo *finfo = fcinfo->flinfo;
Oid foid = finfo->fn_oid;
MemoryContext fcontext;
MemoryContext oldcontext;
Oid rettype;
TupleDesc rettupdesc;
HeapTuple procedureTuple;
Form_pg_proc procedureStruct;
SQLFunctionCachePtr fcache;
List *raw_parsetree_list;
List *queryTree_list;
List *flat_query_list;
List *resulttlist;
ListCell *lc;
Datum tmp;
bool isNull;
@ -642,20 +650,10 @@ init_sql_fcache(FmgrInfo *finfo, Oid collation, bool lazyEvalOK)
MemoryContextSetIdentifier(fcontext, fcache->fname);
/*
* get the result type from the procedure tuple, and check for polymorphic
* result type; if so, find out the actual result type.
* Resolve any polymorphism, obtaining the actual result type, and the
* corresponding tupdesc if it's a rowtype.
*/
rettype = procedureStruct->prorettype;
if (IsPolymorphicType(rettype))
{
rettype = get_fn_expr_rettype(finfo);
if (rettype == InvalidOid) /* this probably should not happen */
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("could not determine actual result type for function declared to return type %s",
format_type_be(procedureStruct->prorettype))));
}
(void) get_call_result_type(fcinfo, &rettype, &rettupdesc);
fcache->rettype = rettype;
@ -728,8 +726,11 @@ init_sql_fcache(FmgrInfo *finfo, Oid collation, bool lazyEvalOK)
* Check that the function returns the type it claims to. Although in
* simple cases this was already done when the function was defined, we
* have to recheck because database objects used in the function's queries
* might have changed type. We'd have to do it anyway if the function had
* any polymorphic arguments.
* might have changed type. We'd have to recheck anyway if the function
* had any polymorphic arguments. Moreover, check_sql_fn_retval takes
* care of injecting any required column type coercions. (But we don't
* ask it to insert nulls for dropped columns; the junkfilter handles
* that.)
*
* Note: we set fcache->returnsTuple according to whether we are returning
* the whole tuple result or just a single column. In the latter case we
@ -738,16 +739,40 @@ init_sql_fcache(FmgrInfo *finfo, Oid collation, bool lazyEvalOK)
* lazy eval mode in that case; otherwise we'd need extra code to expand
* the rowtype column into multiple columns, since we have no way to
* notify the caller that it should do that.)
*
* check_sql_fn_retval will also construct a JunkFilter we can use to
* coerce the returned rowtype to the desired form (unless the result type
* is VOID, in which case there's nothing to coerce to).
*/
fcache->returnsTuple = check_sql_fn_retval(foid,
fcache->returnsTuple = check_sql_fn_retval(flat_query_list,
rettype,
flat_query_list,
NULL,
&fcache->junkFilter);
rettupdesc,
false,
&resulttlist);
/*
* Construct a JunkFilter we can use to coerce the returned rowtype to the
* desired form, unless the result type is VOID, in which case there's
* nothing to coerce to. (XXX Frequently, the JunkFilter isn't doing
* anything very interesting, but much of this module expects it to be
* there anyway.)
*/
if (rettype != VOIDOID)
{
TupleTableSlot *slot = MakeSingleTupleTableSlot(NULL,
&TTSOpsMinimalTuple);
/*
* If the result is composite, *and* we are returning the whole tuple
* result, we need to insert nulls for any dropped columns. In the
* single-column-result case, there might be dropped columns within
* the composite column value, but it's not our problem here. There
* should be no resjunk entries in resulttlist, so in the second case
* the JunkFilter is certainly a no-op.
*/
if (rettupdesc && fcache->returnsTuple)
fcache->junkFilter = ExecInitJunkFilterConversion(resulttlist,
rettupdesc,
slot);
else
fcache->junkFilter = ExecInitJunkFilter(resulttlist, slot);
}
if (fcache->returnsTuple)
{
@ -1049,7 +1074,7 @@ fmgr_sql(PG_FUNCTION_ARGS)
if (fcache == NULL)
{
init_sql_fcache(fcinfo->flinfo, PG_GET_COLLATION(), lazyEvalOK);
init_sql_fcache(fcinfo, PG_GET_COLLATION(), lazyEvalOK);
fcache = (SQLFunctionCachePtr) fcinfo->flinfo->fn_extra;
}
@ -1532,15 +1557,9 @@ check_sql_fn_statements(List *queryTreeList)
* check_sql_fn_retval() -- check return value of a list of sql parse trees.
*
* The return value of a sql function is the value returned by the last
* canSetTag query in the function. We do some ad-hoc type checking here
* to be sure that the user is returning the type he claims. There are
* also a couple of strange-looking features to assist callers in dealing
* with allowed special cases, such as binary-compatible result types.
*
* For a polymorphic function the passed rettype must be the actual resolved
* output type of the function; we should never see a polymorphic pseudotype
* such as ANYELEMENT as rettype. (This means we can't check the type during
* function definition of a polymorphic function.)
* canSetTag query in the function. We do some ad-hoc type checking and
* coercion here to ensure that the function returns what it's supposed to.
* Note that we may actually modify the last query to make it match!
*
* This function returns true if the sql function returns the entire tuple
* result of its final statement, or false if it returns just the first column
@ -1550,45 +1569,47 @@ check_sql_fn_statements(List *queryTreeList)
* Note that because we allow "SELECT rowtype_expression", the result can be
* false even when the declared function return type is a rowtype.
*
* If modifyTargetList isn't NULL, the function will modify the final
* statement's targetlist in two cases:
* (1) if the tlist returns values that are binary-coercible to the expected
* type rather than being exactly the expected type. RelabelType nodes will
* be inserted to make the result types match exactly.
* (2) if there are dropped columns in the declared result rowtype. NULL
* output columns will be inserted in the tlist to match them.
* (Obviously the caller must pass a parsetree that is okay to modify when
* using this flag.) Note that this flag does not affect whether the tlist is
* considered to be a legal match to the result type, only how we react to
* allowed not-exact-match cases. *modifyTargetList will be set true iff
* we had to make any "dangerous" changes that could modify the semantics of
* the statement. If it is set true, the caller should not use the modified
* statement, but for simplicity we apply the changes anyway.
* For a polymorphic function the passed rettype must be the actual resolved
* output type of the function; we should never see a polymorphic pseudotype
* such as ANYELEMENT as rettype. (This means we can't check the type during
* function definition of a polymorphic function.) If the function returns
* composite, the passed rettupdesc should describe the expected output.
* If rettupdesc is NULL, we can't verify that the output matches; that
* should only happen in fmgr_sql_validator(), or when the function returns
* RECORD and the caller doesn't actually care which composite type it is.
* (Typically, rettype and rettupdesc are computed by get_call_result_type
* or a sibling function.)
*
* If junkFilter isn't NULL, then *junkFilter is set to a JunkFilter defined
* to convert the function's tuple result to the correct output tuple type.
* Exception: if the function is defined to return VOID then *junkFilter is
* set to NULL.
* In addition to coercing individual output columns, we can modify the
* output to include dummy NULL columns for any dropped columns appearing
* in rettupdesc. This is done only if the caller asks for it.
*
* If resultTargetList isn't NULL, then *resultTargetList is set to the
* targetlist that defines the final statement's result. Exception: if the
* function is defined to return VOID then *resultTargetList is set to NIL.
*/
bool
check_sql_fn_retval(Oid func_id, Oid rettype, List *queryTreeList,
bool *modifyTargetList,
JunkFilter **junkFilter)
check_sql_fn_retval(List *queryTreeList,
Oid rettype, TupleDesc rettupdesc,
bool insertDroppedCols,
List **resultTargetList)
{
bool is_tuple_result = false;
Query *parse;
List **tlist_ptr;
ListCell *parse_cell;
List *tlist;
int tlistlen;
bool tlist_is_modifiable;
char fn_typtype;
Oid restype;
List *upper_tlist = NIL;
bool upper_tlist_nontrivial = false;
ListCell *lc;
/* Caller must have resolved any polymorphism */
AssertArg(!IsPolymorphicType(rettype));
if (modifyTargetList)
*modifyTargetList = false; /* initialize for no change */
if (junkFilter)
*junkFilter = NULL; /* initialize in case of VOID result */
if (resultTargetList)
*resultTargetList = NIL; /* initialize in case of VOID result */
/*
* If it's declared to return VOID, we don't care what's in the function.
@ -1603,12 +1624,16 @@ check_sql_fn_retval(Oid func_id, Oid rettype, List *queryTreeList,
* the user wrote.
*/
parse = NULL;
parse_cell = NULL;
foreach(lc, queryTreeList)
{
Query *q = lfirst_node(Query, lc);
if (q->canSetTag)
{
parse = q;
parse_cell = lc;
}
}
/*
@ -1625,8 +1650,9 @@ check_sql_fn_retval(Oid func_id, Oid rettype, List *queryTreeList,
if (parse &&
parse->commandType == CMD_SELECT)
{
tlist_ptr = &parse->targetList;
tlist = parse->targetList;
/* tlist is modifiable unless it's a dummy in a setop query */
tlist_is_modifiable = (parse->setOperations == NULL);
}
else if (parse &&
(parse->commandType == CMD_INSERT ||
@ -1634,8 +1660,9 @@ check_sql_fn_retval(Oid func_id, Oid rettype, List *queryTreeList,
parse->commandType == CMD_DELETE) &&
parse->returningList)
{
tlist_ptr = &parse->returningList;
tlist = parse->returningList;
/* returningList can always be modified */
tlist_is_modifiable = true;
}
else
{
@ -1650,7 +1677,12 @@ check_sql_fn_retval(Oid func_id, Oid rettype, List *queryTreeList,
/*
* OK, check that the targetlist returns something matching the declared
* type.
* type, and modify it if necessary. If possible, we insert any coercion
* steps right into the final statement's targetlist. However, that might
* risk changes in the statement's semantics --- we can't safely change
* the output type of a grouping column, for instance. In such cases we
* handle coercions by inserting an extra level of Query that effectively
* just does a projection.
*/
/*
@ -1667,8 +1699,7 @@ check_sql_fn_retval(Oid func_id, Oid rettype, List *queryTreeList,
{
/*
* For scalar-type returns, the target list must have exactly one
* non-junk entry, and its type must agree with what the user
* declared; except we allow binary-compatible types too.
* non-junk entry, and its type must be coercible to rettype.
*/
TargetEntry *tle;
@ -1683,30 +1714,16 @@ check_sql_fn_retval(Oid func_id, Oid rettype, List *queryTreeList,
tle = (TargetEntry *) linitial(tlist);
Assert(!tle->resjunk);
restype = exprType((Node *) tle->expr);
if (!IsBinaryCoercible(restype, rettype))
if (!coerce_fn_result_column(tle, rettype, -1,
tlist_is_modifiable,
&upper_tlist,
&upper_tlist_nontrivial))
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("return type mismatch in function declared to return %s",
format_type_be(rettype)),
errdetail("Actual return type is %s.",
format_type_be(restype))));
if (modifyTargetList && restype != rettype)
{
tle->expr = (Expr *) makeRelabelType(tle->expr,
rettype,
-1,
get_typcollation(rettype),
COERCE_IMPLICIT_CAST);
/* Relabel is dangerous if TLE is a sort/group or setop column */
if (tle->ressortgroupref != 0 || parse->setOperations)
*modifyTargetList = true;
}
/* Set up junk filter if needed */
if (junkFilter)
*junkFilter = ExecInitJunkFilter(tlist,
MakeSingleTupleTableSlot(NULL, &TTSOpsMinimalTuple));
format_type_be(exprType((Node *) tle->expr)))));
}
else if (fn_typtype == TYPTYPE_COMPOSITE || rettype == RECORDOID)
{
@ -1715,26 +1732,29 @@ check_sql_fn_retval(Oid func_id, Oid rettype, List *queryTreeList,
*
* Note that we will not consider a domain over composite to be a
* "rowtype" return type; it goes through the scalar case above. This
* is because SQL functions don't provide any implicit casting to the
* result type, so there is no way to produce a domain-over-composite
* result except by computing it as an explicit single-column result.
* is because we only provide column-by-column implicit casting, and
* will not cast the complete record result. So the only way to
* produce a domain-over-composite result is to compute it as an
* explicit single-column result. The single-composite-column code
* path just below could handle such cases, but it won't be reached.
*/
TupleDesc tupdesc;
int tupnatts; /* physical number of columns in tuple */
int tuplogcols; /* # of nondeleted columns in tuple */
int colindex; /* physical column index */
List *newtlist; /* new non-junk tlist entries */
List *junkattrs; /* new junk tlist entries */
/*
* If the target list is of length 1, and the type of the varnode in
* the target list matches the declared return type, this is okay.
* This can happen, for example, where the body of the function is
* 'SELECT func2()', where func2 has the same composite return type as
* the function that's calling it.
* If the target list has one non-junk entry, and that expression has
* or can be coerced to the declared return type, take it as the
* result. This allows, for example, 'SELECT func2()', where func2
* has the same composite return type as the function that's calling
* it. This provision creates some ambiguity --- maybe the expression
* was meant to be the lone field of the composite result --- but it
* works well enough as long as we don't get too enthusiastic about
* inventing coercions from scalar to composite types.
*
* XXX Note that if rettype is RECORD, the IsBinaryCoercible check
* will succeed for any composite restype. For the moment we rely on
* XXX Note that if rettype is RECORD and the expression is of a named
* composite type, or vice versa, this coercion will succeed, whether
* or not the record type really matches. For the moment we rely on
* runtime type checking to catch any discrepancy, but it'd be nice to
* do better at parse time.
*/
@ -1743,78 +1763,46 @@ check_sql_fn_retval(Oid func_id, Oid rettype, List *queryTreeList,
TargetEntry *tle = (TargetEntry *) linitial(tlist);
Assert(!tle->resjunk);
restype = exprType((Node *) tle->expr);
if (IsBinaryCoercible(restype, rettype))
if (coerce_fn_result_column(tle, rettype, -1,
tlist_is_modifiable,
&upper_tlist,
&upper_tlist_nontrivial))
{
if (modifyTargetList && restype != rettype)
{
tle->expr = (Expr *) makeRelabelType(tle->expr,
rettype,
-1,
get_typcollation(rettype),
COERCE_IMPLICIT_CAST);
/* Relabel is dangerous if sort/group or setop column */
if (tle->ressortgroupref != 0 || parse->setOperations)
*modifyTargetList = true;
}
/* Set up junk filter if needed */
if (junkFilter)
{
TupleTableSlot *slot =
MakeSingleTupleTableSlot(NULL, &TTSOpsMinimalTuple);
*junkFilter = ExecInitJunkFilter(tlist, slot);
}
return false; /* NOT returning whole tuple */
/* Note that we're NOT setting is_tuple_result */
goto tlist_coercion_finished;
}
}
/*
* Is the rowtype fixed, or determined only at runtime? (Note we
* cannot see TYPEFUNC_COMPOSITE_DOMAIN here.)
* If the caller didn't provide an expected tupdesc, we can't do any
* further checking. Assume we're returning the whole tuple.
*/
if (get_func_result_type(func_id, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
if (rettupdesc == NULL)
{
/*
* Assume we are returning the whole tuple. Crosschecking against
* what the caller expects will happen at runtime.
*/
if (junkFilter)
{
TupleTableSlot *slot;
slot = MakeSingleTupleTableSlot(NULL, &TTSOpsMinimalTuple);
*junkFilter = ExecInitJunkFilter(tlist, slot);
}
/* Return tlist if requested */
if (resultTargetList)
*resultTargetList = tlist;
return true;
}
Assert(tupdesc);
/*
* Verify that the targetlist matches the return tuple type. We scan
* the non-deleted attributes to ensure that they match the datatypes
* of the non-resjunk columns. For deleted attributes, insert NULL
* result columns if the caller asked for that.
* Verify that the targetlist matches the return tuple type. We scan
* the non-resjunk columns, and coerce them if necessary to match the
* datatypes of the non-deleted attributes. For deleted attributes,
* insert NULL result columns if the caller asked for that.
*/
tupnatts = tupdesc->natts;
tupnatts = rettupdesc->natts;
tuplogcols = 0; /* we'll count nondeleted cols as we go */
colindex = 0;
newtlist = NIL; /* these are only used if modifyTargetList */
junkattrs = NIL;
foreach(lc, tlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(lc);
Form_pg_attribute attr;
Oid tletype;
Oid atttype;
/* resjunk columns can simply be ignored */
if (tle->resjunk)
{
if (modifyTargetList)
junkattrs = lappend(junkattrs, tle);
continue;
}
do
{
@ -1825,8 +1813,8 @@ check_sql_fn_retval(Oid func_id, Oid rettype, List *queryTreeList,
errmsg("return type mismatch in function declared to return %s",
format_type_be(rettype)),
errdetail("Final statement returns too many columns.")));
attr = TupleDescAttr(tupdesc, colindex - 1);
if (attr->attisdropped && modifyTargetList)
attr = TupleDescAttr(rettupdesc, colindex - 1);
if (attr->attisdropped && insertDroppedCols)
{
Expr *null_expr;
@ -1838,57 +1826,41 @@ check_sql_fn_retval(Oid func_id, Oid rettype, List *queryTreeList,
(Datum) 0,
true, /* isnull */
true /* byval */ );
newtlist = lappend(newtlist,
makeTargetEntry(null_expr,
colindex,
NULL,
false));
/* NULL insertion is dangerous in a setop */
if (parse->setOperations)
*modifyTargetList = true;
upper_tlist = lappend(upper_tlist,
makeTargetEntry(null_expr,
list_length(upper_tlist) + 1,
NULL,
false));
upper_tlist_nontrivial = true;
}
} while (attr->attisdropped);
tuplogcols++;
tletype = exprType((Node *) tle->expr);
atttype = attr->atttypid;
if (!IsBinaryCoercible(tletype, atttype))
if (!coerce_fn_result_column(tle,
attr->atttypid, attr->atttypmod,
tlist_is_modifiable,
&upper_tlist,
&upper_tlist_nontrivial))
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("return type mismatch in function declared to return %s",
format_type_be(rettype)),
errdetail("Final statement returns %s instead of %s at column %d.",
format_type_be(tletype),
format_type_be(atttype),
format_type_be(exprType((Node *) tle->expr)),
format_type_be(attr->atttypid),
tuplogcols)));
if (modifyTargetList)
{
if (tletype != atttype)
{
tle->expr = (Expr *) makeRelabelType(tle->expr,
atttype,
-1,
get_typcollation(atttype),
COERCE_IMPLICIT_CAST);
/* Relabel is dangerous if sort/group or setop column */
if (tle->ressortgroupref != 0 || parse->setOperations)
*modifyTargetList = true;
}
tle->resno = colindex;
newtlist = lappend(newtlist, tle);
}
}
/* remaining columns in tupdesc had better all be dropped */
/* remaining columns in rettupdesc had better all be dropped */
for (colindex++; colindex <= tupnatts; colindex++)
{
if (!TupleDescAttr(tupdesc, colindex - 1)->attisdropped)
if (!TupleDescAttr(rettupdesc, colindex - 1)->attisdropped)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("return type mismatch in function declared to return %s",
format_type_be(rettype)),
errdetail("Final statement returns too few columns.")));
if (modifyTargetList)
if (insertDroppedCols)
{
Expr *null_expr;
@ -1900,43 +1872,17 @@ check_sql_fn_retval(Oid func_id, Oid rettype, List *queryTreeList,
(Datum) 0,
true, /* isnull */
true /* byval */ );
newtlist = lappend(newtlist,
makeTargetEntry(null_expr,
colindex,
NULL,
false));
/* NULL insertion is dangerous in a setop */
if (parse->setOperations)
*modifyTargetList = true;
upper_tlist = lappend(upper_tlist,
makeTargetEntry(null_expr,
list_length(upper_tlist) + 1,
NULL,
false));
upper_tlist_nontrivial = true;
}
}
if (modifyTargetList)
{
/* ensure resjunk columns are numbered correctly */
foreach(lc, junkattrs)
{
TargetEntry *tle = (TargetEntry *) lfirst(lc);
tle->resno = colindex++;
}
/* replace the tlist with the modified one */
*tlist_ptr = list_concat(newtlist, junkattrs);
}
/* Set up junk filter if needed */
if (junkFilter)
{
TupleTableSlot *slot =
MakeSingleTupleTableSlot(NULL, &TTSOpsMinimalTuple);
*junkFilter = ExecInitJunkFilterConversion(tlist,
CreateTupleDescCopy(tupdesc),
slot);
}
/* Report that we are returning entire tuple result */
return true;
is_tuple_result = true;
}
else
ereport(ERROR,
@ -1944,7 +1890,135 @@ check_sql_fn_retval(Oid func_id, Oid rettype, List *queryTreeList,
errmsg("return type %s is not supported for SQL functions",
format_type_be(rettype))));
return false;
tlist_coercion_finished:
/*
* If necessary, modify the final Query by injecting an extra Query level
* that just performs a projection. (It'd be dubious to do this to a
* non-SELECT query, but we never have to; RETURNING lists can always be
* modified in-place.)
*/
if (upper_tlist_nontrivial)
{
Query *newquery;
List *colnames;
RangeTblEntry *rte;
RangeTblRef *rtr;
Assert(parse->commandType == CMD_SELECT);
/* Most of the upper Query struct can be left as zeroes/nulls */
newquery = makeNode(Query);
newquery->commandType = CMD_SELECT;
newquery->querySource = parse->querySource;
newquery->canSetTag = true;
newquery->targetList = upper_tlist;
/* We need a moderately realistic colnames list for the subquery RTE */
colnames = NIL;
foreach(lc, parse->targetList)
{
TargetEntry *tle = (TargetEntry *) lfirst(lc);
if (tle->resjunk)
continue;
colnames = lappend(colnames,
makeString(tle->resname ? tle->resname : ""));
}
/* Build a suitable RTE for the subquery */
rte = makeNode(RangeTblEntry);
rte->rtekind = RTE_SUBQUERY;
rte->subquery = parse;
rte->eref = rte->alias = makeAlias("*SELECT*", colnames);
rte->lateral = false;
rte->inh = false;
rte->inFromCl = true;
newquery->rtable = list_make1(rte);
rtr = makeNode(RangeTblRef);
rtr->rtindex = 1;
newquery->jointree = makeFromExpr(list_make1(rtr), NULL);
/* Replace original query in the correct element of the query list */
lfirst(parse_cell) = newquery;
}
/* Return tlist (possibly modified) if requested */
if (resultTargetList)
*resultTargetList = upper_tlist;
return is_tuple_result;
}
/*
* Process one function result column for check_sql_fn_retval
*
* Coerce the output value to the required type/typmod, and add a column
* to *upper_tlist for it. Set *upper_tlist_nontrivial to true if we
* add an upper tlist item that's not just a Var.
*
* Returns true if OK, false if could not coerce to required type
* (in which case, no changes have been made)
*/
static bool
coerce_fn_result_column(TargetEntry *src_tle,
Oid res_type,
int32 res_typmod,
bool tlist_is_modifiable,
List **upper_tlist,
bool *upper_tlist_nontrivial)
{
TargetEntry *new_tle;
Expr *new_tle_expr;
Node *cast_result;
/*
* If the TLE has a sortgroupref marking, don't change it, as it probably
* is referenced by ORDER BY, DISTINCT, etc, and changing its type would
* break query semantics. Otherwise, it's safe to modify in-place unless
* the query as a whole has issues with that.
*/
if (tlist_is_modifiable && src_tle->ressortgroupref == 0)
{
/* OK to modify src_tle in place, if necessary */
cast_result = coerce_to_target_type(NULL,
(Node *) src_tle->expr,
exprType((Node *) src_tle->expr),
res_type, res_typmod,
COERCION_ASSIGNMENT,
COERCE_IMPLICIT_CAST,
-1);
if (cast_result == NULL)
return false;
src_tle->expr = (Expr *) cast_result;
/* Make a Var referencing the possibly-modified TLE */
new_tle_expr = (Expr *) makeVarFromTargetEntry(1, src_tle);
}
else
{
/* Any casting must happen in the upper tlist */
Var *var = makeVarFromTargetEntry(1, src_tle);
cast_result = coerce_to_target_type(NULL,
(Node *) var,
var->vartype,
res_type, res_typmod,
COERCION_ASSIGNMENT,
COERCE_IMPLICIT_CAST,
-1);
if (cast_result == NULL)
return false;
/* Did the coercion actually do anything? */
if (cast_result != (Node *) var)
*upper_tlist_nontrivial = true;
new_tle_expr = (Expr *) cast_result;
}
new_tle = makeTargetEntry(new_tle_expr,
list_length(*upper_tlist) + 1,
src_tle->resname, false);
*upper_tlist = lappend(*upper_tlist, new_tle);
return true;
}

131
src/backend/optimizer/util/clauses.c
View File

@ -155,7 +155,6 @@ 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);
/*****************************************************************************
@ -4399,15 +4398,16 @@ inline_function(Oid funcid, Oid result_type, Oid result_collid,
char *src;
Datum tmp;
bool isNull;
bool modifyTargetList;
MemoryContext oldcxt;
MemoryContext mycxt;
inline_error_callback_arg callback_arg;
ErrorContextCallback sqlerrcontext;
FuncExpr *fexpr;
SQLFunctionParseInfoPtr pinfo;
TupleDesc rettupdesc;
ParseState *pstate;
List *raw_parsetree_list;
List *querytree_list;
Query *querytree;
Node *newexpr;
int *usecounts;
@ -4472,8 +4472,8 @@ inline_function(Oid funcid, Oid result_type, Oid result_collid,
/*
* Set up to handle parameters while parsing the function body. We need a
* dummy FuncExpr node containing the already-simplified arguments to pass
* to prepare_sql_fn_parse_info. (It is really only needed if there are
* some polymorphic arguments, but for simplicity we always build it.)
* to prepare_sql_fn_parse_info. (In some cases we don't really need
* that, but for simplicity we always build it.)
*/
fexpr = makeNode(FuncExpr);
fexpr->funcid = funcid;
@ -4490,6 +4490,11 @@ inline_function(Oid funcid, Oid result_type, Oid result_collid,
(Node *) fexpr,
input_collid);
/* fexpr also provides a convenient way to resolve a composite result */
(void) get_expr_result_type((Node *) fexpr,
NULL,
&rettupdesc);
/*
* We just do parsing and parse analysis, not rewriting, because rewriting
* will not affect table-free-SELECT-only queries, which is all that we
@ -4542,16 +4547,24 @@ inline_function(Oid funcid, Oid result_type, Oid result_collid,
* Make sure the function (still) returns what it's declared to. This
* will raise an error if wrong, but that's okay since the function would
* fail at runtime anyway. Note that check_sql_fn_retval will also insert
* a RelabelType if needed to make the tlist expression match the declared
* a coercion if needed to make the tlist expression match the declared
* type of the function.
*
* Note: we do not try this until we have verified that no rewriting was
* needed; that's probably not important, but let's be careful.
*/
if (check_sql_fn_retval(funcid, result_type, list_make1(querytree),
&modifyTargetList, NULL))
querytree_list = list_make1(querytree);
if (check_sql_fn_retval(querytree_list, result_type, rettupdesc,
false, NULL))
goto fail; /* reject whole-tuple-result cases */
/*
* Given the tests above, check_sql_fn_retval shouldn't have decided to
* inject a projection step, but let's just make sure.
*/
if (querytree != linitial(querytree_list))
goto fail;
/* Now we can grab the tlist expression */
newexpr = (Node *) ((TargetEntry *) linitial(querytree->targetList))->expr;
@ -4566,9 +4579,6 @@ inline_function(Oid funcid, Oid result_type, Oid result_collid,
if (exprType(newexpr) != result_type)
goto fail;
/* check_sql_fn_retval couldn't have made any dangerous tlist changes */
Assert(!modifyTargetList);
/*
* Additional validity checks on the expression. It mustn't be more
* volatile than the surrounding function (this is to avoid breaking hacks
@ -4877,12 +4887,13 @@ inline_set_returning_function(PlannerInfo *root, RangeTblEntry *rte)
char *src;
Datum tmp;
bool isNull;
bool modifyTargetList;
MemoryContext oldcxt;
MemoryContext mycxt;
inline_error_callback_arg callback_arg;
ErrorContextCallback sqlerrcontext;
SQLFunctionParseInfoPtr pinfo;
TypeFuncClass functypclass;
TupleDesc rettupdesc;
List *raw_parsetree_list;
List *querytree_list;
Query *querytree;
@ -5012,6 +5023,18 @@ inline_set_returning_function(PlannerInfo *root, RangeTblEntry *rte)
(Node *) fexpr,
fexpr->inputcollid);
/*
* Also resolve the actual function result tupdesc, if composite. If the
* function is just declared to return RECORD, dig the info out of the AS
* clause.
*/
functypclass = get_expr_result_type((Node *) fexpr, NULL, &rettupdesc);
if (functypclass == TYPEFUNC_RECORD)
rettupdesc = BuildDescFromLists(rtfunc->funccolnames,
rtfunc->funccoltypes,
rtfunc->funccoltypmods,
rtfunc->funccolcollations);
/*
* Parse, analyze, and rewrite (unlike inline_function(), we can't skip
* rewriting here). We can fail as soon as we find more than one query,
@ -5040,43 +5063,28 @@ inline_set_returning_function(PlannerInfo *root, RangeTblEntry *rte)
* Make sure the function (still) returns what it's declared to. This
* will raise an error if wrong, but that's okay since the function would
* fail at runtime anyway. Note that check_sql_fn_retval will also insert
* RelabelType(s) and/or NULL columns if needed to make the tlist
* expression(s) match the declared type of the function.
* coercions if needed to make the tlist expression(s) match the declared
* type of the function. We also ask it to insert dummy NULL columns for
* any dropped columns in rettupdesc, so that the elements of the modified
* tlist match up to the attribute numbers.
*
* If the function returns a composite type, don't inline unless the check
* shows it's returning a whole tuple result; otherwise what it's
* returning is a single composite column which is not what we need. (Like
* check_sql_fn_retval, we deliberately exclude domains over composite
* here.)
* returning is a single composite column which is not what we need.
*/
if (!check_sql_fn_retval(func_oid, fexpr->funcresulttype,
querytree_list,
&modifyTargetList, NULL) &&
(get_typtype(fexpr->funcresulttype) == TYPTYPE_COMPOSITE ||
fexpr->funcresulttype == RECORDOID))
if (!check_sql_fn_retval(querytree_list,
fexpr->funcresulttype, rettupdesc,
true, NULL) &&
(functypclass == TYPEFUNC_COMPOSITE ||
functypclass == TYPEFUNC_COMPOSITE_DOMAIN ||
functypclass == TYPEFUNC_RECORD))
goto fail; /* reject not-whole-tuple-result cases */
/*
* If we had to modify the tlist to make it match, and the statement is
* one in which changing the tlist contents could change semantics, we
* have to punt and not inline.
* check_sql_fn_retval might've inserted a projection step, but that's
* fine; just make sure we use the upper Query.
*/
if (modifyTargetList)
goto fail;
/*
* 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.) We don't have to do this for functions
* with declared OUT parameters, even though their funcresulttype is
* RECORDOID, so check get_func_result_type too.
*/
if (fexpr->funcresulttype == RECORDOID &&
get_func_result_type(func_oid, NULL, NULL) == TYPEFUNC_RECORD &&
!tlist_matches_coltypelist(querytree->targetList,
rtfunc->funccoltypes))
goto fail;
querytree = linitial(querytree_list);
/*
* Looks good --- substitute parameters into the query.
@ -5181,46 +5189,3 @@ 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(coltypelist, clistitem);
if (exprType((Node *) tle->expr) != coltype)
return false; /* column type mismatch */
}
if (clistitem != NULL)
return false; /* too few tlist items */
return true;
}

8
src/include/executor/functions.h
View File

@ -31,10 +31,10 @@ extern void sql_fn_parser_setup(struct ParseState *pstate,
extern void check_sql_fn_statements(List *queryTreeList);
extern bool check_sql_fn_retval(Oid func_id, Oid rettype,
List *queryTreeList,
bool *modifyTargetList,
JunkFilter **junkFilter);
extern bool check_sql_fn_retval(List *queryTreeList,
Oid rettype, TupleDesc rettupdesc,
bool insertDroppedCols,
List **resultTargetList);
extern DestReceiver *CreateSQLFunctionDestReceiver(void);

210
src/test/regress/expected/rangefuncs.out
View File

@ -1820,6 +1820,67 @@ select * from array_to_set(array['one', 'two']); -- fail
ERROR: a column definition list is required for functions returning "record"
LINE 1: select * from array_to_set(array['one', 'two']);
^
-- after-the-fact coercion of the columns is now possible, too
select * from array_to_set(array['one', 'two']) as t(f1 numeric(4,2),f2 text);
f1 | f2
------+-----
1.00 | one
2.00 | two
(2 rows)
-- and if it doesn't work, you get a compile-time not run-time error
select * from array_to_set(array['one', 'two']) as t(f1 point,f2 text);
ERROR: return type mismatch in function declared to return record
DETAIL: Final statement returns integer instead of point at column 1.
CONTEXT: SQL function "array_to_set" during startup
-- with "strict", this function can't be inlined in FROM
explain (verbose, costs off)
select * from array_to_set(array['one', 'two']) as t(f1 numeric(4,2),f2 text);
QUERY PLAN
----------------------------------------------------
Function Scan on public.array_to_set t
Output: f1, f2
Function Call: array_to_set('{one,two}'::text[])
(3 rows)
-- but without, it can be:
create or replace function array_to_set(anyarray) returns setof record as $$
select i AS "index", $1[i] AS "value" from generate_subscripts($1, 1) i
$$ language sql immutable;
select array_to_set(array['one', 'two']);
array_to_set
--------------
(1,one)
(2,two)
(2 rows)
select * from array_to_set(array['one', 'two']) as t(f1 int,f2 text);
f1 | f2
----+-----
1 | one
2 | two
(2 rows)
select * from array_to_set(array['one', 'two']) as t(f1 numeric(4,2),f2 text);
f1 | f2
------+-----
1.00 | one
2.00 | two
(2 rows)
select * from array_to_set(array['one', 'two']) as t(f1 point,f2 text);
ERROR: return type mismatch in function declared to return record
DETAIL: Final statement returns integer instead of point at column 1.
CONTEXT: SQL function "array_to_set" during inlining
explain (verbose, costs off)
select * from array_to_set(array['one', 'two']) as t(f1 numeric(4,2),f2 text);
QUERY PLAN
--------------------------------------------------------------
Function Scan on pg_catalog.generate_subscripts i
Output: i.i, ('{one,two}'::text[])[i.i]
Function Call: generate_subscripts('{one,two}'::text[], 1)
(3 rows)
create temp table rngfunc(f1 int8, f2 int8);
create function testrngfunc() returns record as $$
insert into rngfunc values (1,2) returning *;
@ -1863,6 +1924,140 @@ ERROR: a column definition list is required for functions returning "record"
LINE 1: select * from testrngfunc();
^
drop function testrngfunc();
-- Check that typmod imposed by a composite type is honored
create type rngfunc_type as (f1 numeric(35,6), f2 numeric(35,2));
create function testrngfunc() returns rngfunc_type as $$
select 7.136178319899999964, 7.136178319899999964;
$$ language sql immutable;
explain (verbose, costs off)
select testrngfunc();
QUERY PLAN
-------------------------------------------
Result
Output: '(7.136178,7.14)'::rngfunc_type
(2 rows)
select testrngfunc();
testrngfunc
-----------------
(7.136178,7.14)
(1 row)
explain (verbose, costs off)
select * from testrngfunc();
QUERY PLAN
--------------------------------------------------
Function Scan on testrngfunc
Output: f1, f2
Function Call: '(7.136178,7.14)'::rngfunc_type
(3 rows)
select * from testrngfunc();
f1 | f2
----------+------
7.136178 | 7.14
(1 row)
create or replace function testrngfunc() returns rngfunc_type as $$
select 7.136178319899999964, 7.136178319899999964;
$$ language sql volatile;
explain (verbose, costs off)
select testrngfunc();
QUERY PLAN
-------------------------
Result
Output: testrngfunc()
(2 rows)
select testrngfunc();
testrngfunc
-----------------
(7.136178,7.14)
(1 row)
explain (verbose, costs off)
select * from testrngfunc();
QUERY PLAN
-------------------------------------
Function Scan on public.testrngfunc
Output: f1, f2
Function Call: testrngfunc()
(3 rows)
select * from testrngfunc();
f1 | f2
----------+------
7.136178 | 7.14
(1 row)
drop function testrngfunc();
create function testrngfunc() returns setof rngfunc_type as $$
select 7.136178319899999964, 7.136178319899999964;
$$ language sql immutable;
explain (verbose, costs off)
select testrngfunc();
QUERY PLAN
-------------------------
ProjectSet
Output: testrngfunc()
-> Result
(3 rows)
select testrngfunc();
testrngfunc
-----------------
(7.136178,7.14)
(1 row)
explain (verbose, costs off)
select * from testrngfunc();
QUERY PLAN
--------------------------------------------------------
Result
Output: 7.136178::numeric(35,6), 7.14::numeric(35,2)
(2 rows)
select * from testrngfunc();
f1 | f2
----------+------
7.136178 | 7.14
(1 row)
create or replace function testrngfunc() returns setof rngfunc_type as $$
select 7.136178319899999964, 7.136178319899999964;
$$ language sql volatile;
explain (verbose, costs off)
select testrngfunc();
QUERY PLAN
-------------------------
ProjectSet
Output: testrngfunc()
-> Result
(3 rows)
select testrngfunc();
testrngfunc
-----------------
(7.136178,7.14)
(1 row)
explain (verbose, costs off)
select * from testrngfunc();
QUERY PLAN
-------------------------------------
Function Scan on public.testrngfunc
Output: f1, f2
Function Call: testrngfunc()
(3 rows)
select * from testrngfunc();
f1 | f2
----------+------
7.136178 | 7.14
(1 row)
drop type rngfunc_type cascade;
NOTICE: drop cascades to function testrngfunc()
--
-- Check some cases involving added/dropped columns in a rowtype result
--
@ -1955,7 +2150,7 @@ drop view usersview;
drop function get_first_user();
drop function get_users();
drop table users;
-- this won't get inlined because of type coercion, but it shouldn't fail
-- check behavior with type coercion required for a set-op
create or replace function rngfuncbar() returns setof text as
$$ select 'foo'::varchar union all select 'bar'::varchar ; $$
language sql stable;
@ -1973,6 +2168,19 @@ select * from rngfuncbar();
bar
(2 rows)
-- this function is now inlinable, too:
explain (verbose, costs off) select * from rngfuncbar();
QUERY PLAN
------------------------------------------------
Result
Output: ('foo'::character varying)
-> Append
-> Result
Output: 'foo'::character varying
-> Result
Output: 'bar'::character varying
(7 rows)
drop function rngfuncbar();
-- check handling of a SQL function with multiple OUT params (bug #5777)
create or replace function rngfuncbar(out integer, out numeric) as

76
src/test/regress/sql/rangefuncs.sql
View File

@ -515,6 +515,27 @@ $$ language sql strict immutable;
select array_to_set(array['one', 'two']);
select * from array_to_set(array['one', 'two']) as t(f1 int,f2 text);
select * from array_to_set(array['one', 'two']); -- fail
-- after-the-fact coercion of the columns is now possible, too
select * from array_to_set(array['one', 'two']) as t(f1 numeric(4,2),f2 text);
-- and if it doesn't work, you get a compile-time not run-time error
select * from array_to_set(array['one', 'two']) as t(f1 point,f2 text);
-- with "strict", this function can't be inlined in FROM
explain (verbose, costs off)
select * from array_to_set(array['one', 'two']) as t(f1 numeric(4,2),f2 text);
-- but without, it can be:
create or replace function array_to_set(anyarray) returns setof record as $$
select i AS "index", $1[i] AS "value" from generate_subscripts($1, 1) i
$$ language sql immutable;
select array_to_set(array['one', 'two']);
select * from array_to_set(array['one', 'two']) as t(f1 int,f2 text);
select * from array_to_set(array['one', 'two']) as t(f1 numeric(4,2),f2 text);
select * from array_to_set(array['one', 'two']) as t(f1 point,f2 text);
explain (verbose, costs off)
select * from array_to_set(array['one', 'two']) as t(f1 numeric(4,2),f2 text);
create temp table rngfunc(f1 int8, f2 int8);
@ -538,6 +559,57 @@ select * from testrngfunc(); -- fail
drop function testrngfunc();
-- Check that typmod imposed by a composite type is honored
create type rngfunc_type as (f1 numeric(35,6), f2 numeric(35,2));
create function testrngfunc() returns rngfunc_type as $$
select 7.136178319899999964, 7.136178319899999964;
$$ language sql immutable;
explain (verbose, costs off)
select testrngfunc();
select testrngfunc();
explain (verbose, costs off)
select * from testrngfunc();
select * from testrngfunc();
create or replace function testrngfunc() returns rngfunc_type as $$
select 7.136178319899999964, 7.136178319899999964;
$$ language sql volatile;
explain (verbose, costs off)
select testrngfunc();
select testrngfunc();
explain (verbose, costs off)
select * from testrngfunc();
select * from testrngfunc();
drop function testrngfunc();
create function testrngfunc() returns setof rngfunc_type as $$
select 7.136178319899999964, 7.136178319899999964;
$$ language sql immutable;
explain (verbose, costs off)
select testrngfunc();
select testrngfunc();
explain (verbose, costs off)
select * from testrngfunc();
select * from testrngfunc();
create or replace function testrngfunc() returns setof rngfunc_type as $$
select 7.136178319899999964, 7.136178319899999964;
$$ language sql volatile;
explain (verbose, costs off)
select testrngfunc();
select testrngfunc();
explain (verbose, costs off)
select * from testrngfunc();
select * from testrngfunc();
drop type rngfunc_type cascade;
--
-- Check some cases involving added/dropped columns in a rowtype result
--
@ -585,7 +657,7 @@ drop function get_first_user();
drop function get_users();
drop table users;
-- this won't get inlined because of type coercion, but it shouldn't fail
-- check behavior with type coercion required for a set-op
create or replace function rngfuncbar() returns setof text as
$$ select 'foo'::varchar union all select 'bar'::varchar ; $$
@ -593,6 +665,8 @@ language sql stable;
select rngfuncbar();
select * from rngfuncbar();
-- this function is now inlinable, too:
explain (verbose, costs off) select * from rngfuncbar();
drop function rngfuncbar();