Allow polymorphic aggregates to have non-polymorphic state data types.

Before 9.4, such an aggregate couldn't be declared, because its final
function would have to have polymorphic result type but no polymorphic
argument, which CREATE FUNCTION would quite properly reject.  The
ordered-set-aggregate patch found a workaround: allow the final function
to be declared as accepting additional dummy arguments that have types
matching the aggregate's regular input arguments.  However, we failed
to notice that this problem applies just as much to regular aggregates,
despite the fact that we had a built-in regular aggregate array_agg()
that was known to be undeclarable in SQL because its final function
had an illegal signature.  So what we should have done, and what this
patch does, is to decouple the extra-dummy-arguments behavior from
ordered-set aggregates and make it generally available for all aggregate
declarations.  We have to put this into 9.4 rather than waiting till
later because it slightly alters the rules for declaring ordered-set
aggregates.

The patch turned out a bit bigger than I'd hoped because it proved
necessary to record the extra-arguments option in a new pg_aggregate
column.  I'd thought we could just look at the final function's pronargs
at runtime, but that didn't work well for variadic final functions.
It's probably just as well though, because it simplifies life for pg_dump
to record the option explicitly.

While at it, fix array_agg() to have a valid final-function signature,
and add an opr_sanity test to notice future deviations from polymorphic
consistency.  I also marked the percentile_cont() aggregates as not
needing extra arguments, since they don't.

doc/src/sgml/catalogs.sgml

@@ -404,6 +404,18 @@
       <entry><literal><link linkend="catalog-pg-proc"><structname>pg_proc</structname></link>.oid</literal></entry>
       <entry>Final function for moving-aggregate mode (zero if none)</entry>
      </row>
+     <row>
+      <entry><structfield>aggfinalextra</structfield></entry>
+      <entry><type>bool</type></entry>
+      <entry></entry>
+      <entry>True to pass extra dummy arguments to aggfinalfn</entry>
+     </row>
+     <row>
+      <entry><structfield>aggmfinalextra</structfield></entry>
+      <entry><type>bool</type></entry>
+      <entry></entry>
+      <entry>True to pass extra dummy arguments to aggmfinalfn</entry>
+     </row>
      <row>
       <entry><structfield>aggsortop</structfield></entry>
       <entry><type>oid</type></entry>

doc/src/sgml/ref/create_aggregate.sgml

@@ -26,12 +26,14 @@ CREATE AGGREGATE <replaceable class="parameter">name</replaceable> ( [ <replacea
     STYPE = <replaceable class="PARAMETER">state_data_type</replaceable>
     [ , SSPACE = <replaceable class="PARAMETER">state_data_size</replaceable> ]
     [ , FINALFUNC = <replaceable class="PARAMETER">ffunc</replaceable> ]
+    [ , FINALFUNC_EXTRA ]
     [ , INITCOND = <replaceable class="PARAMETER">initial_condition</replaceable> ]
     [ , MSFUNC = <replaceable class="PARAMETER">msfunc</replaceable> ]
     [ , MINVFUNC = <replaceable class="PARAMETER">minvfunc</replaceable> ]
     [ , MSTYPE = <replaceable class="PARAMETER">mstate_data_type</replaceable> ]
     [ , MSSPACE = <replaceable class="PARAMETER">mstate_data_size</replaceable> ]
     [ , MFINALFUNC = <replaceable class="PARAMETER">mffunc</replaceable> ]
+    [ , MFINALFUNC_EXTRA ]
     [ , MINITCOND = <replaceable class="PARAMETER">minitial_condition</replaceable> ]
     [ , SORTOP = <replaceable class="PARAMETER">sort_operator</replaceable> ]
 )
@@ -42,6 +44,7 @@ CREATE AGGREGATE <replaceable class="parameter">name</replaceable> ( [ [ <replac
     STYPE = <replaceable class="PARAMETER">state_data_type</replaceable>
     [ , SSPACE = <replaceable class="PARAMETER">state_data_size</replaceable> ]
     [ , FINALFUNC = <replaceable class="PARAMETER">ffunc</replaceable> ]
+    [ , FINALFUNC_EXTRA ]
     [ , INITCOND = <replaceable class="PARAMETER">initial_condition</replaceable> ]
     [ , HYPOTHETICAL ]
 )
@@ -54,12 +57,14 @@ CREATE AGGREGATE <replaceable class="PARAMETER">name</replaceable> (
     STYPE = <replaceable class="PARAMETER">state_data_type</replaceable>
     [ , SSPACE = <replaceable class="PARAMETER">state_data_size</replaceable> ]
     [ , FINALFUNC = <replaceable class="PARAMETER">ffunc</replaceable> ]
+    [ , FINALFUNC_EXTRA ]
     [ , INITCOND = <replaceable class="PARAMETER">initial_condition</replaceable> ]
     [ , MSFUNC = <replaceable class="PARAMETER">sfunc</replaceable> ]
     [ , MINVFUNC = <replaceable class="PARAMETER">invfunc</replaceable> ]
     [ , MSTYPE = <replaceable class="PARAMETER">state_data_type</replaceable> ]
     [ , MSSPACE = <replaceable class="PARAMETER">state_data_size</replaceable> ]
     [ , MFINALFUNC = <replaceable class="PARAMETER">ffunc</replaceable> ]
+    [ , MFINALFUNC_EXTRA ]
     [ , MINITCOND = <replaceable class="PARAMETER">initial_condition</replaceable> ]
     [ , SORTOP = <replaceable class="PARAMETER">sort_operator</replaceable> ]
 )
@@ -166,12 +171,25 @@ CREATE AGGREGATE <replaceable class="PARAMETER">name</replaceable> (
    input rows.
   </para>
 
+  <para>
+   Sometimes it is useful to declare the final function as taking not just
+   the state value, but extra parameters corresponding to the aggregate's
+   input values.  The main reason for doing this is if the final function
+   is polymorphic and the state value's data type would be inadequate to
+   pin down the result type.  These extra parameters are always passed as
+   NULL (and so the final function must not be strict when
+   the <literal>FINALFUNC_EXTRA</> option is used), but nonetheless they
+   are valid parameters.  The final function could for example make use
+   of <function>get_fn_expr_argtype</> to identify the actual argument type
+   in the current call.
+  </para>
+
   <para>
    An aggregate can optionally support <firstterm>moving-aggregate mode</>,
    as described in <xref linkend="xaggr-moving-aggregates">.  This requires
    specifying the <literal>MSFUNC</>, <literal>MINVFUNC</>,
    and <literal>MSTYPE</> parameters, and optionally
-   the <literal>MSPACE</>, <literal>MFINALFUNC</>,
+   the <literal>MSPACE</>, <literal>MFINALFUNC</>, <literal>MFINALFUNC_EXTRA</>,
    and <literal>MINITCOND</> parameters.  Except for <literal>MINVFUNC</>,
    these parameters work like the corresponding simple-aggregate parameters
    without <literal>M</>; they define a separate implementation of the
@@ -361,12 +379,16 @@ SELECT col FROM tab ORDER BY col USING sortop LIMIT 1;
      <para>
       For ordered-set (including hypothetical-set) aggregates, the
       final function receives not only the final state value,
-      but also the values of all the direct arguments, followed by
-      null values corresponding to each aggregated argument.
-      (The reason for including the aggregated arguments in the function
-      signature is that this may be necessary to allow correct resolution
-      of the aggregate result type, when a polymorphic aggregate is
-      being defined.)
+      but also the values of all the direct arguments.
+     </para>
+
+     <para>
+      If <literal>FINALFUNC_EXTRA</> is specified, then in addition to the
+      final state value and any direct arguments, the final function
+      receives extra NULL values corresponding to the aggregate's regular
+      (aggregated) arguments.  This is mainly useful to allow correct
+      resolution of the aggregate result type when a polymorphic aggregate
+      is being defined.
      </para>
     </listitem>
    </varlistentry>
@@ -438,9 +460,11 @@ SELECT col FROM tab ORDER BY col USING sortop LIMIT 1;
       The name of the final function called to compute the aggregate's
       result after all input rows have been traversed, when using
       moving-aggregate mode.  This works the same as <replaceable>ffunc</>,
-      except that its input type is <replaceable>mstate_data_type</>.
+      except that its first argument's type
+      is <replaceable>mstate_data_type</> and extra dummy arguments are
+      specified by writing <literal>MFINALFUNC_EXTRA</>.
       The aggregate result type determined by <replaceable>mffunc</>
-      and <replaceable>mstate_data_type</> must match that determined by the
+      or <replaceable>mstate_data_type</> must match that determined by the
       aggregate's regular implementation.
      </para>
     </listitem>
@@ -494,6 +518,13 @@ SELECT col FROM tab ORDER BY col USING sortop LIMIT 1;
  <refsect1>
   <title>Notes</title>
 
+   <para>
+    In parameters that specify support function names, you can write
+    a schema name if needed, for example <literal>SFUNC = public.sum</>.
+    Do not write argument types there, however &mdash; the argument types
+    of the support functions are determined from other parameters.
+   </para>
+
    <para>
     If an aggregate supports moving-aggregate mode, it will improve
     calculation efficiency when the aggregate is used as a window function

doc/src/sgml/xaggr.sgml

@@ -127,7 +127,7 @@ CREATE AGGREGATE avg (float8)
    <function>float8_accum</> requires a three-element array, not just
    two elements, because it accumulates the sum of squares as well as
    the sum and count of the inputs.  This is so that it can be used for
-   some other aggregates besides <function>avg</>.
+   some other aggregates as well as <function>avg</>.
    </para>
   </note>
 
@@ -182,7 +182,7 @@ CREATE AGGREGATE avg (float8)
    The inverse transition function is passed the current state value and the
    aggregate input value(s) for the earliest row included in the current
    state.  It must reconstruct what the state value would have been if the
-   given input value had never been aggregated, but only the rows following
+   given input row had never been aggregated, but only the rows following
    it.  This sometimes requires that the forward transition function keep
    more state than is needed for plain aggregation mode.  Therefore, the
    moving-aggregate mode uses a completely separate implementation from the
@@ -339,6 +339,47 @@ SELECT attrelid::regclass, array_accum(atttypid::regtype)
 </programlisting>
   </para>
 
+  <para>
+   Ordinarily, an aggregate function with a polymorphic result type has a
+   polymorphic state type, as in the above example.  This is necessary
+   because otherwise the final function cannot be declared sensibly: it
+   would need to have a polymorphic result type but no polymorphic argument
+   type, which <command>CREATE FUNCTION</> will reject on the grounds that
+   the result type cannot be deduced from a call.  But sometimes it is
+   inconvenient to use a polymorphic state type.  The most common case is
+   where the aggregate support functions are to be written in C and the
+   state type should be declared as <type>internal</> because there is
+   no SQL-level equivalent for it.  To address this case, it is possible to
+   declare the final function as taking extra <quote>dummy</> arguments
+   that match the input arguments of the aggregate.  Such dummy arguments
+   are always passed as NULLs since no specific value is available when the
+   final function is called.  Their only use is to allow a polymorphic
+   final function's result type to be connected to the aggregate's input
+   type(s).  For example, the definition of the built-in
+   aggregate <function>array_agg</> is equivalent to
+
+<programlisting>
+CREATE FUNCTION array_agg_transfn(internal, anyelement)
+  RETURNS internal ...;
+CREATE FUNCTION array_agg_finalfn(internal, anyelement)
+  RETURNS anyarray ...;
+
+CREATE AGGREGATE array_agg (anyelement)
+(
+    sfunc = array_agg_transfn,
+    stype = internal,
+    finalfunc = array_agg_finalfn,
+    finalfunc_extra
+);
+</programlisting>
+
+   Here, the <literal>finalfunc_extra</> option specifies that the final
+   function receives, in addition to the state value, extra dummy
+   argument(s) corresponding to the aggregate's input argument(s).
+   The extra <type>anyelement</> argument allows the declaration
+   of <function>array_agg_finalfn</> to be valid.
+  </para>
+
   <para>
    An aggregate function can be made to accept a varying number of arguments
    by declaring its last argument as a <literal>VARIADIC</> array, in much
@@ -401,15 +442,23 @@ SELECT myaggregate(a, b, c ORDER BY a) FROM ...
    definition of <function>percentile_disc</> is equivalent to:
 
 <programlisting>
+CREATE FUNCTION ordered_set_transition(internal, anyelement)
+  RETURNS internal ...;
+CREATE FUNCTION percentile_disc_final(internal, float8, anyelement)
+  RETURNS anyelement ...;
+
 CREATE AGGREGATE percentile_disc (float8 ORDER BY anyelement)
 (
     sfunc = ordered_set_transition,
     stype = internal,
-    finalfunc = percentile_disc_final
+    finalfunc = percentile_disc_final,
+    finalfunc_extra
 );
 </programlisting>
 
-   which could be used to obtain a median household income like this:
+   This aggregate takes a <type>float8</> direct argument (the percentile
+   fraction) and an aggregated input that can be of any sortable data type.
+   It could be used to obtain a median household income like this:
 
 <programlisting>
 SELECT percentile_disc(0.5) WITHIN GROUP (ORDER BY income) FROM households;
@@ -447,25 +496,12 @@ SELECT percentile_disc(0.5) WITHIN GROUP (ORDER BY income) FROM households;
    same definition as for normal aggregates, but note that the direct
    arguments (if any) are not provided.  The final function receives
    the last state value, the values of the direct arguments if any,
-   and null values corresponding to the aggregated input(s).  While the
-   null values seem useless at first sight, they are important because
-   they make it possible to include the data types of the aggregated
-   input(s) in the final function's signature, which may be necessary
-   to resolve the output type of a polymorphic aggregate.  For example,
-   the built-in <function>mode()</> ordered-set aggregate takes a
-   single aggregated column of any sortable data type and returns a
-   value of that same type.  This is possible because the final function
-   is declared as <literal>mode_final(internal, anyelement) returns
-   anyelement</>, with the <type>anyelement</> parameter corresponding
-   to the dummy null argument that represents the aggregated column.
-   The actual data is conveyed in the <type>internal</>-type state
-   value, but type resolution needs a parse-time indication of what the
-   result data type will be, and the dummy argument provides that.
-   In the example of <function>percentile_disc</>, the support functions
-   are respectively declared as
-   <literal>ordered_set_transition(internal, "any") returns internal</>
-   and <literal>percentile_disc_final(internal, float8, anyelement)
-   returns anyelement</>.
+   and (if <literal>finalfunc_extra</> is specified) NULL values
+   corresponding to the aggregated input(s).  As with normal
+   aggregates, <literal>finalfunc_extra</> is only really useful if the
+   aggregate is polymorphic; then the extra dummy argument(s) are needed
+   to connect the final function's result type to the aggregate's input
+   type(s).
   </para>
 
   <para>

src/backend/catalog/pg_aggregate.c

@@ -60,6 +60,8 @@ AggregateCreate(const char *aggName,
 				List *aggmtransfnName,
 				List *aggminvtransfnName,
 				List *aggmfinalfnName,
+				bool finalfnExtraArgs,
+				bool mfinalfnExtraArgs,
 				List *aggsortopName,
 				Oid aggTransType,
 				int32 aggTransSpace,
@@ -344,48 +346,46 @@ AggregateCreate(const char *aggName,
 		ReleaseSysCache(tup);
 	}
 
-	/*
-	 * Set up fnArgs for looking up finalfn(s)
-	 *
-	 * For ordinary aggs, the finalfn just takes the transtype.  For
-	 * ordered-set aggs, it takes the transtype plus all args.	(The
-	 * aggregated args are useless at runtime, and are actually passed as
-	 * NULLs, but we may need them in the function signature to allow
-	 * resolution of a polymorphic agg's result type.)
-	 */
-	fnArgs[0] = aggTransType;
-	if (AGGKIND_IS_ORDERED_SET(aggKind))
-	{
-		nargs_finalfn = numArgs + 1;
-		memcpy(fnArgs + 1, aggArgTypes, numArgs * sizeof(Oid));
-	}
-	else
-	{
-		nargs_finalfn = 1;
-		/* variadic-ness of the aggregate doesn't affect finalfn */
-		variadicArgType = InvalidOid;
-	}
-
 	/* handle finalfn, if supplied */
 	if (aggfinalfnName)
 	{
+		/*
+		 * If finalfnExtraArgs is specified, the transfn takes the transtype
+		 * plus all args; otherwise, it just takes the transtype plus any
+		 * direct args.  (Non-direct args are useless at runtime, and are
+		 * actually passed as NULLs, but we may need them in the function
+		 * signature to allow resolution of a polymorphic agg's result type.)
+		 */
+		Oid			ffnVariadicArgType = variadicArgType;
+
+		fnArgs[0] = aggTransType;
+		memcpy(fnArgs + 1, aggArgTypes, numArgs * sizeof(Oid));
+		if (finalfnExtraArgs)
+			nargs_finalfn = numArgs + 1;
+		else
+		{
+			nargs_finalfn = numDirectArgs + 1;
+			if (numDirectArgs < numArgs)
+			{
+				/* variadic argument doesn't affect finalfn */
+				ffnVariadicArgType = InvalidOid;
+			}
+		}
+
 		finalfn = lookup_agg_function(aggfinalfnName, nargs_finalfn,
-									  fnArgs, variadicArgType,
+									  fnArgs, ffnVariadicArgType,
 									  &finaltype);
 
 		/*
-		 * The finalfn of an ordered-set agg will certainly be passed at least
-		 * one null argument, so complain if it's strict.  Nothing bad would
-		 * happen at runtime (you'd just get a null result), but it's surely
-		 * not what the user wants, so let's complain now.
-		 *
-		 * Note: it's likely that a strict transfn would also be a mistake,
-		 * but the case isn't quite so airtight, so we let that pass.
+		 * When finalfnExtraArgs is specified, the finalfn will certainly be
+		 * passed at least one null argument, so complain if it's strict.
+		 * Nothing bad would happen at runtime (you'd just get a null result),
+		 * but it's surely not what the user wants, so let's complain now.
 		 */
-		if (AGGKIND_IS_ORDERED_SET(aggKind) && func_strict(finalfn))
+		if (finalfnExtraArgs && func_strict(finalfn))
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
-					 errmsg("final function of an ordered-set aggregate must not be declared STRICT")));
+					 errmsg("final function with extra arguments must not be declared STRICT")));
 	}
 	else
 	{
@@ -434,21 +434,34 @@ AggregateCreate(const char *aggName,
 		if (aggmfinalfnName)
 		{
 			/*
-			 * The arguments are the same as for the regular finalfn, except
-			 * that the transition data type might be different.  So re-use
-			 * the fnArgs values set up above, except for that one.
+			 * The arguments are figured the same way as for the regular
+			 * finalfn, but using aggmTransType and mfinalfnExtraArgs.
 			 */
+			Oid			ffnVariadicArgType = variadicArgType;
+
 			fnArgs[0] = aggmTransType;
+			memcpy(fnArgs + 1, aggArgTypes, numArgs * sizeof(Oid));
+			if (mfinalfnExtraArgs)
+				nargs_finalfn = numArgs + 1;
+			else
+			{
+				nargs_finalfn = numDirectArgs + 1;
+				if (numDirectArgs < numArgs)
+				{
+					/* variadic argument doesn't affect finalfn */
+					ffnVariadicArgType = InvalidOid;
+				}
+			}
 
 			mfinalfn = lookup_agg_function(aggmfinalfnName, nargs_finalfn,
-										   fnArgs, variadicArgType,
+										   fnArgs, ffnVariadicArgType,
 										   &rettype);
 
-			/* As above, check strictness if it's an ordered-set agg */
-			if (AGGKIND_IS_ORDERED_SET(aggKind) && func_strict(mfinalfn))
+			/* As above, check strictness if mfinalfnExtraArgs is given */
+			if (mfinalfnExtraArgs && func_strict(mfinalfn))
 				ereport(ERROR,
 						(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
-						 errmsg("final function of an ordered-set aggregate must not be declared STRICT")));
+						 errmsg("final function with extra arguments must not be declared STRICT")));
 		}
 		else
 		{
@@ -554,6 +567,8 @@ AggregateCreate(const char *aggName,
 	values[Anum_pg_aggregate_aggmtransfn - 1] = ObjectIdGetDatum(mtransfn);
 	values[Anum_pg_aggregate_aggminvtransfn - 1] = ObjectIdGetDatum(minvtransfn);
 	values[Anum_pg_aggregate_aggmfinalfn - 1] = ObjectIdGetDatum(mfinalfn);
+	values[Anum_pg_aggregate_aggfinalextra - 1] = BoolGetDatum(finalfnExtraArgs);
+	values[Anum_pg_aggregate_aggmfinalextra - 1] = BoolGetDatum(mfinalfnExtraArgs);
 	values[Anum_pg_aggregate_aggsortop - 1] = ObjectIdGetDatum(sortop);
 	values[Anum_pg_aggregate_aggtranstype - 1] = ObjectIdGetDatum(aggTransType);
 	values[Anum_pg_aggregate_aggtransspace - 1] = Int32GetDatum(aggTransSpace);

src/backend/commands/aggregatecmds.c

@@ -64,6 +64,8 @@ DefineAggregate(List *name, List *args, bool oldstyle, List *parameters,
 	List	   *mtransfuncName = NIL;
 	List	   *minvtransfuncName = NIL;
 	List	   *mfinalfuncName = NIL;
+	bool		finalfuncExtraArgs = false;
+	bool		mfinalfuncExtraArgs = false;
 	List	   *sortoperatorName = NIL;
 	TypeName   *baseType = NULL;
 	TypeName   *transType = NULL;
@@ -128,6 +130,10 @@ DefineAggregate(List *name, List *args, bool oldstyle, List *parameters,
 			minvtransfuncName = defGetQualifiedName(defel);
 		else if (pg_strcasecmp(defel->defname, "mfinalfunc") == 0)
 			mfinalfuncName = defGetQualifiedName(defel);
+		else if (pg_strcasecmp(defel->defname, "finalfunc_extra") == 0)
+			finalfuncExtraArgs = defGetBoolean(defel);
+		else if (pg_strcasecmp(defel->defname, "mfinalfunc_extra") == 0)
+			mfinalfuncExtraArgs = defGetBoolean(defel);
 		else if (pg_strcasecmp(defel->defname, "sortop") == 0)
 			sortoperatorName = defGetQualifiedName(defel);
 		else if (pg_strcasecmp(defel->defname, "basetype") == 0)
@@ -380,6 +386,8 @@ DefineAggregate(List *name, List *args, bool oldstyle, List *parameters,
 						   mtransfuncName,		/* fwd trans function name */
 						   minvtransfuncName,	/* inv trans function name */
 						   mfinalfuncName,		/* final function name */
+						   finalfuncExtraArgs,
+						   mfinalfuncExtraArgs,
 						   sortoperatorName,	/* sort operator name */
 						   transTypeId, /* transition data type */
 						   transSpace,	/* transition space */

src/backend/executor/nodeAgg.c

@@ -37,11 +37,12 @@
  *
  *	  Ordered-set aggregates are treated specially in one other way: we
  *	  evaluate any "direct" arguments and pass them to the finalfunc along
- *	  with the transition value.  In addition, NULL placeholders are
- *	  provided to match the remaining finalfunc arguments, which correspond
- *	  to the aggregated expressions.  (These arguments have no use at
- *	  runtime, but may be needed to allow resolution of a polymorphic
- *	  aggregate's result type.)
+ *	  with the transition value.
+ *
+ *	  A finalfunc can have additional arguments beyond the transvalue and
+ *	  any "direct" arguments, corresponding to the input arguments of the
+ *	  aggregate.  These are always just passed as NULL.  Such arguments may be
+ *	  needed to allow resolution of a polymorphic aggregate's result type.
  *
  *	  We compute aggregate input expressions and run the transition functions
  *	  in a temporary econtext (aggstate->tmpcontext).  This is reset at
@@ -151,6 +152,14 @@ typedef struct AggStatePerAggData
 	 */
 	int			numTransInputs;
 
+	/*
+	 * Number of arguments to pass to the finalfn.	This is always at least 1
+	 * (the transition state value) plus any ordered-set direct args. If the
+	 * finalfn wants extra args then we pass nulls corresponding to the
+	 * aggregated input columns.
+	 */
+	int			numFinalArgs;
+
 	/* Oids of transfer functions */
 	Oid			transfn_oid;
 	Oid			finalfn_oid;	/* may be InvalidOid */
@@ -797,6 +806,8 @@ finalize_aggregate(AggState *aggstate,
 	/*
 	 * Evaluate any direct arguments.  We do this even if there's no finalfn
 	 * (which is unlikely anyway), so that side-effects happen as expected.
+	 * The direct arguments go into arg positions 1 and up, leaving position 0
+	 * for the transition state value.
 	 */
 	i = 1;
 	foreach(lc, peraggstate->aggrefstate->aggdirectargs)
@@ -816,19 +827,7 @@ finalize_aggregate(AggState *aggstate,
 	 */
 	if (OidIsValid(peraggstate->finalfn_oid))
 	{
-		int			numFinalArgs;
-
-		/*
-		 * Identify number of arguments being passed to the finalfn.  For a
-		 * plain agg it's just one (the transition state value).  For
-		 * ordered-set aggs we also pass the direct argument(s), plus nulls
-		 * corresponding to the aggregate-input columns.
-		 */
-		if (AGGKIND_IS_ORDERED_SET(peraggstate->aggref->aggkind))
-			numFinalArgs = peraggstate->numArguments + 1;
-		else
-			numFinalArgs = 1;
-		Assert(i <= numFinalArgs);
+		int			numFinalArgs = peraggstate->numFinalArgs;
 
 		/* set up aggstate->curperagg for AggGetAggref() */
 		aggstate->curperagg = peraggstate;
@@ -844,12 +843,11 @@ finalize_aggregate(AggState *aggstate,
 		anynull |= pergroupstate->transValueIsNull;
 
 		/* Fill any remaining argument positions with nulls */
-		while (i < numFinalArgs)
+		for (; i < numFinalArgs; i++)
 		{
 			fcinfo.arg[i] = (Datum) 0;
 			fcinfo.argnull[i] = true;
 			anynull = true;
-			i++;
 		}
 
 		if (fcinfo.flinfo->fn_strict && anynull)
@@ -1776,12 +1774,18 @@ ExecInitAgg(Agg *node, EState *estate, int eflags)
 		numInputs = list_length(aggref->args);
 		peraggstate->numInputs = numInputs;
 
-		/* Detect how many columns to pass to the transfn */
+		/* Detect how many arguments to pass to the transfn */
 		if (AGGKIND_IS_ORDERED_SET(aggref->aggkind))
 			peraggstate->numTransInputs = numInputs;
 		else
 			peraggstate->numTransInputs = numArguments;
 
+		/* Detect how many arguments to pass to the finalfn */
+		if (aggform->aggfinalextra)
+			peraggstate->numFinalArgs = numArguments + 1;
+		else
+			peraggstate->numFinalArgs = numDirectArgs + 1;
+
 		/* resolve actual type of transition state, if polymorphic */
 		aggtranstype = resolve_aggregate_transtype(aggref->aggfnoid,
 												   aggform->aggtranstype,
@@ -1792,7 +1796,7 @@ ExecInitAgg(Agg *node, EState *estate, int eflags)
 		build_aggregate_fnexprs(inputTypes,
 								numArguments,
 								numDirectArgs,
-								AGGKIND_IS_ORDERED_SET(aggref->aggkind),
+								peraggstate->numFinalArgs,
 								aggref->aggvariadic,
 								aggtranstype,
 								aggref->aggtype,

src/backend/executor/nodeWindowAgg.c

@@ -116,6 +116,8 @@ typedef struct WindowStatePerAggData
 	FmgrInfo	invtransfn;
 	FmgrInfo	finalfn;
 
+	int			numFinalArgs;	/* number of arguments to pass to finalfn */
+
 	/*
 	 * initial value from pg_aggregate entry
 	 */
@@ -557,14 +559,28 @@ finalize_windowaggregate(WindowAggState *winstate,
 	 */
 	if (OidIsValid(peraggstate->finalfn_oid))
 	{
+		int			numFinalArgs = peraggstate->numFinalArgs;
 		FunctionCallInfoData fcinfo;
+		bool		anynull;
+		int			i;
 
-		InitFunctionCallInfoData(fcinfo, &(peraggstate->finalfn), 1,
+		InitFunctionCallInfoData(fcinfo, &(peraggstate->finalfn),
+								 numFinalArgs,
 								 perfuncstate->winCollation,
 								 (void *) winstate, NULL);
 		fcinfo.arg[0] = peraggstate->transValue;
 		fcinfo.argnull[0] = peraggstate->transValueIsNull;
-		if (fcinfo.flinfo->fn_strict && peraggstate->transValueIsNull)
+		anynull = peraggstate->transValueIsNull;
+
+		/* Fill any remaining argument positions with nulls */
+		for (i = 1; i < numFinalArgs; i++)
+		{
+			fcinfo.arg[i] = (Datum) 0;
+			fcinfo.argnull[i] = true;
+			anynull = true;
+		}
+
+		if (fcinfo.flinfo->fn_strict && anynull)
 		{
 			/* don't call a strict function with NULL inputs */
 			*result = (Datum) 0;
@@ -2089,6 +2105,7 @@ initialize_peragg(WindowAggState *winstate, WindowFunc *wfunc,
 	Oid			transfn_oid,
 				invtransfn_oid,
 				finalfn_oid;
+	bool		finalextra;
 	Expr	   *transfnexpr,
 			   *invtransfnexpr,
 			   *finalfnexpr;
@@ -2127,6 +2144,7 @@ initialize_peragg(WindowAggState *winstate, WindowFunc *wfunc,
 		peraggstate->transfn_oid = transfn_oid = aggform->aggmtransfn;
 		peraggstate->invtransfn_oid = invtransfn_oid = aggform->aggminvtransfn;
 		peraggstate->finalfn_oid = finalfn_oid = aggform->aggmfinalfn;
+		finalextra = aggform->aggmfinalextra;
 		aggtranstype = aggform->aggmtranstype;
 		initvalAttNo = Anum_pg_aggregate_aggminitval;
 	}
@@ -2135,6 +2153,7 @@ initialize_peragg(WindowAggState *winstate, WindowFunc *wfunc,
 		peraggstate->transfn_oid = transfn_oid = aggform->aggtransfn;
 		peraggstate->invtransfn_oid = invtransfn_oid = InvalidOid;
 		peraggstate->finalfn_oid = finalfn_oid = aggform->aggfinalfn;
+		finalextra = aggform->aggfinalextra;
 		aggtranstype = aggform->aggtranstype;
 		initvalAttNo = Anum_pg_aggregate_agginitval;
 	}
@@ -2185,6 +2204,12 @@ initialize_peragg(WindowAggState *winstate, WindowFunc *wfunc,
 		}
 	}
 
+	/* Detect how many arguments to pass to the finalfn */
+	if (finalextra)
+		peraggstate->numFinalArgs = numArguments + 1;
+	else
+		peraggstate->numFinalArgs = 1;
+
 	/* resolve actual type of transition state, if polymorphic */
 	aggtranstype = resolve_aggregate_transtype(wfunc->winfnoid,
 											   aggtranstype,
@@ -2195,7 +2220,7 @@ initialize_peragg(WindowAggState *winstate, WindowFunc *wfunc,
 	build_aggregate_fnexprs(inputTypes,
 							numArguments,
 							0,	/* no ordered-set window functions yet */
-							false,
+							peraggstate->numFinalArgs,
 							false,		/* no variadic window functions yet */
 							aggtranstype,
 							wfunc->wintype,
@@ -2207,6 +2232,7 @@ initialize_peragg(WindowAggState *winstate, WindowFunc *wfunc,
 							&invtransfnexpr,
 							&finalfnexpr);
 
+	/* set up infrastructure for calling the transfn(s) and finalfn */
 	fmgr_info(transfn_oid, &peraggstate->transfn);
 	fmgr_info_set_expr((Node *) transfnexpr, &peraggstate->transfn);
 
@@ -2222,6 +2248,7 @@ initialize_peragg(WindowAggState *winstate, WindowFunc *wfunc,
 		fmgr_info_set_expr((Node *) finalfnexpr, &peraggstate->finalfn);
 	}
 
+	/* get info about relevant datatypes */
 	get_typlenbyval(wfunc->wintype,
 					&peraggstate->resulttypeLen,
 					&peraggstate->resulttypeByVal);

src/backend/parser/parse_agg.c

@@ -1199,7 +1199,7 @@ void
 build_aggregate_fnexprs(Oid *agg_input_types,
 						int agg_num_inputs,
 						int agg_num_direct_inputs,
-						bool agg_ordered_set,
+						int num_finalfn_inputs,
 						bool agg_variadic,
 						Oid agg_state_type,
 						Oid agg_result_type,
@@ -1292,19 +1292,17 @@ build_aggregate_fnexprs(Oid *agg_input_types,
 	argp->location = -1;
 	args = list_make1(argp);
 
-	if (agg_ordered_set)
+	/* finalfn may take additional args, which match agg's input types */
+	for (i = 0; i < num_finalfn_inputs - 1; i++)
 	{
-		for (i = 0; i < agg_num_inputs; i++)
-		{
-			argp = makeNode(Param);
-			argp->paramkind = PARAM_EXEC;
-			argp->paramid = -1;
-			argp->paramtype = agg_input_types[i];
-			argp->paramtypmod = -1;
-			argp->paramcollid = agg_input_collation;
-			argp->location = -1;
-			args = lappend(args, argp);
-		}
+		argp = makeNode(Param);
+		argp->paramkind = PARAM_EXEC;
+		argp->paramid = -1;
+		argp->paramtype = agg_input_types[i];
+		argp->paramtypmod = -1;
+		argp->paramcollid = agg_input_collation;
+		argp->location = -1;
+		args = lappend(args, argp);
 	}
 
 	*finalfnexpr = (Expr *) makeFuncExpr(finalfn_oid,

src/bin/pg_dump/pg_dump.c

@@ -11551,6 +11551,8 @@ dumpAgg(Archive *fout, AggInfo *agginfo)
 	int			i_aggmtransfn;
 	int			i_aggminvtransfn;
 	int			i_aggmfinalfn;
+	int			i_aggfinalextra;
+	int			i_aggmfinalextra;
 	int			i_aggsortop;
 	int			i_hypothetical;
 	int			i_aggtranstype;
@@ -11565,6 +11567,8 @@ dumpAgg(Archive *fout, AggInfo *agginfo)
 	const char *aggmtransfn;
 	const char *aggminvtransfn;
 	const char *aggmfinalfn;
+	bool		aggfinalextra;
+	bool		aggmfinalextra;
 	const char *aggsortop;
 	char	   *aggsortconvop;
 	bool		hypothetical;
@@ -11596,11 +11600,12 @@ dumpAgg(Archive *fout, AggInfo *agginfo)
 						  "aggfinalfn, aggtranstype::pg_catalog.regtype, "
 						  "aggmtransfn, aggminvtransfn, aggmfinalfn, "
 						  "aggmtranstype::pg_catalog.regtype, "
+						  "aggfinalextra, aggmfinalextra, "
 						  "aggsortop::pg_catalog.regoperator, "
-						  "(aggkind = 'h') as hypothetical, "
+						  "(aggkind = 'h') AS hypothetical, "
 						  "aggtransspace, agginitval, "
 						  "aggmtransspace, aggminitval, "
-						  "'t'::boolean AS convertok, "
+						  "true AS convertok, "
 						  "pg_catalog.pg_get_function_arguments(p.oid) AS funcargs, "
 						  "pg_catalog.pg_get_function_identity_arguments(p.oid) AS funciargs "
 					  "FROM pg_catalog.pg_aggregate a, pg_catalog.pg_proc p "
@@ -11614,11 +11619,12 @@ dumpAgg(Archive *fout, AggInfo *agginfo)
 						  "aggfinalfn, aggtranstype::pg_catalog.regtype, "
 						  "'-' AS aggmtransfn, '-' AS aggminvtransfn, "
 						  "'-' AS aggmfinalfn, 0 AS aggmtranstype, "
+						  "false AS aggfinalextra, false AS aggmfinalextra, "
 						  "aggsortop::pg_catalog.regoperator, "
-						  "false as hypothetical, "
+						  "false AS hypothetical, "
 						  "0 AS aggtransspace, agginitval, "
 						  "0 AS aggmtransspace, NULL AS aggminitval, "
-						  "'t'::boolean AS convertok, "
+						  "true AS convertok, "
 						  "pg_catalog.pg_get_function_arguments(p.oid) AS funcargs, "
 						  "pg_catalog.pg_get_function_identity_arguments(p.oid) AS funciargs "
 					  "FROM pg_catalog.pg_aggregate a, pg_catalog.pg_proc p "
@@ -11632,11 +11638,12 @@ dumpAgg(Archive *fout, AggInfo *agginfo)
 						  "aggfinalfn, aggtranstype::pg_catalog.regtype, "
 						  "'-' AS aggmtransfn, '-' AS aggminvtransfn, "
 						  "'-' AS aggmfinalfn, 0 AS aggmtranstype, "
+						  "false AS aggfinalextra, false AS aggmfinalextra, "
 						  "aggsortop::pg_catalog.regoperator, "
-						  "false as hypothetical, "
+						  "false AS hypothetical, "
 						  "0 AS aggtransspace, agginitval, "
 						  "0 AS aggmtransspace, NULL AS aggminitval, "
-						  "'t'::boolean AS convertok "
+						  "true AS convertok "
 						  "FROM pg_catalog.pg_aggregate a, pg_catalog.pg_proc p "
 						  "WHERE a.aggfnoid = p.oid "
 						  "AND p.oid = '%u'::pg_catalog.oid",
@@ -11648,11 +11655,12 @@ dumpAgg(Archive *fout, AggInfo *agginfo)
 						  "aggfinalfn, aggtranstype::pg_catalog.regtype, "
 						  "'-' AS aggmtransfn, '-' AS aggminvtransfn, "
 						  "'-' AS aggmfinalfn, 0 AS aggmtranstype, "
+						  "false AS aggfinalextra, false AS aggmfinalextra, "
 						  "0 AS aggsortop, "
-						  "'f'::boolean as hypothetical, "
+						  "false AS hypothetical, "
 						  "0 AS aggtransspace, agginitval, "
 						  "0 AS aggmtransspace, NULL AS aggminitval, "
-						  "'t'::boolean AS convertok "
+						  "true AS convertok "
 					  "FROM pg_catalog.pg_aggregate a, pg_catalog.pg_proc p "
 						  "WHERE a.aggfnoid = p.oid "
 						  "AND p.oid = '%u'::pg_catalog.oid",
@@ -11664,11 +11672,12 @@ dumpAgg(Archive *fout, AggInfo *agginfo)
 						  "format_type(aggtranstype, NULL) AS aggtranstype, "
 						  "'-' AS aggmtransfn, '-' AS aggminvtransfn, "
 						  "'-' AS aggmfinalfn, 0 AS aggmtranstype, "
+						  "false AS aggfinalextra, false AS aggmfinalextra, "
 						  "0 AS aggsortop, "
-						  "'f'::boolean as hypothetical, "
+						  "false AS hypothetical, "
 						  "0 AS aggtransspace, agginitval, "
 						  "0 AS aggmtransspace, NULL AS aggminitval, "
-						  "'t'::boolean AS convertok "
+						  "true AS convertok "
 						  "FROM pg_aggregate "
 						  "WHERE oid = '%u'::oid",
 						  agginfo->aggfn.dobj.catId.oid);
@@ -11680,8 +11689,9 @@ dumpAgg(Archive *fout, AggInfo *agginfo)
 						  "(SELECT typname FROM pg_type WHERE oid = aggtranstype1) AS aggtranstype, "
 						  "'-' AS aggmtransfn, '-' AS aggminvtransfn, "
 						  "'-' AS aggmfinalfn, 0 AS aggmtranstype, "
+						  "false AS aggfinalextra, false AS aggmfinalextra, "
 						  "0 AS aggsortop, "
-						  "'f'::boolean as hypothetical, "
+						  "false AS hypothetical, "
 						  "0 AS aggtransspace, agginitval1 AS agginitval, "
 						  "0 AS aggmtransspace, NULL AS aggminitval, "
 						  "(aggtransfn2 = 0 and aggtranstype2 = 0 and agginitval2 is null) AS convertok "
@@ -11697,6 +11707,8 @@ dumpAgg(Archive *fout, AggInfo *agginfo)
 	i_aggmtransfn = PQfnumber(res, "aggmtransfn");
 	i_aggminvtransfn = PQfnumber(res, "aggminvtransfn");
 	i_aggmfinalfn = PQfnumber(res, "aggmfinalfn");
+	i_aggfinalextra = PQfnumber(res, "aggfinalextra");
+	i_aggmfinalextra = PQfnumber(res, "aggmfinalextra");
 	i_aggsortop = PQfnumber(res, "aggsortop");
 	i_hypothetical = PQfnumber(res, "hypothetical");
 	i_aggtranstype = PQfnumber(res, "aggtranstype");
@@ -11712,6 +11724,8 @@ dumpAgg(Archive *fout, AggInfo *agginfo)
 	aggmtransfn = PQgetvalue(res, 0, i_aggmtransfn);
 	aggminvtransfn = PQgetvalue(res, 0, i_aggminvtransfn);
 	aggmfinalfn = PQgetvalue(res, 0, i_aggmfinalfn);
+	aggfinalextra = (PQgetvalue(res, 0, i_aggfinalextra)[0] == 't');
+	aggmfinalextra = (PQgetvalue(res, 0, i_aggmfinalextra)[0] == 't');
 	aggsortop = PQgetvalue(res, 0, i_aggsortop);
 	hypothetical = (PQgetvalue(res, 0, i_hypothetical)[0] == 't');
 	aggtranstype = PQgetvalue(res, 0, i_aggtranstype);
@@ -11791,6 +11805,8 @@ dumpAgg(Archive *fout, AggInfo *agginfo)
 	{
 		appendPQExpBuffer(details, ",\n    FINALFUNC = %s",
 						  aggfinalfn);
+		if (aggfinalextra)
+			appendPQExpBufferStr(details, ",\n    FINALFUNC_EXTRA");
 	}
 
 	if (strcmp(aggmtransfn, "-") != 0)
@@ -11817,6 +11833,8 @@ dumpAgg(Archive *fout, AggInfo *agginfo)
 	{
 		appendPQExpBuffer(details, ",\n    MFINALFUNC = %s",
 						  aggmfinalfn);
+		if (aggmfinalextra)
+			appendPQExpBufferStr(details, ",\n    MFINALFUNC_EXTRA");
 	}
 
 	aggsortconvop = convertOperatorReference(fout, aggsortop);

src/include/catalog/catversion.h

@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	201404161
+#define CATALOG_VERSION_NO	201404231
 
 #endif

src/include/catalog/pg_proc.h

@@ -879,7 +879,7 @@ DATA(insert OID = 3168 (  array_replace    PGNSP PGUID 12 1 0 0 0 f f f f f f i
 DESCR("replace any occurrences of an element in an array");
 DATA(insert OID = 2333 (  array_agg_transfn   PGNSP PGUID 12 1 0 0 0 f f f f f f i 2 0 2281 "2281 2283" _null_ _null_ _null_ _null_ array_agg_transfn _null_ _null_ _null_ ));
 DESCR("aggregate transition function");
-DATA(insert OID = 2334 (  array_agg_finalfn   PGNSP PGUID 12 1 0 0 0 f f f f f f i 1 0 2277 "2281" _null_ _null_ _null_ _null_ array_agg_finalfn _null_ _null_ _null_ ));
+DATA(insert OID = 2334 (  array_agg_finalfn   PGNSP PGUID 12 1 0 0 0 f f f f f f i 2 0 2277 "2281 2283" _null_ _null_ _null_ _null_ array_agg_finalfn _null_ _null_ _null_ ));
 DESCR("aggregate final function");
 DATA(insert OID = 2335 (  array_agg		   PGNSP PGUID 12 1 0 0 0 t f f f f f i 1 0 2277 "2283" _null_ _null_ _null_ _null_ aggregate_dummy _null_ _null_ _null_ ));
 DESCR("concatenate aggregate input into an array");
@@ -4990,11 +4990,11 @@ DATA(insert OID = 3973 ( percentile_disc_final	PGNSP PGUID 12 1 0 0 0 f f f f f
 DESCR("aggregate final function");
 DATA(insert OID = 3974 ( percentile_cont		PGNSP PGUID 12 1 0 0 0 t f f f f f i 2 0 701 "701 701" _null_ _null_ _null_ _null_ aggregate_dummy _null_ _null_ _null_ ));
 DESCR("continuous distribution percentile");
-DATA(insert OID = 3975 ( percentile_cont_float8_final	PGNSP PGUID 12 1 0 0 0 f f f f f f i 3 0 701 "2281 701 701" _null_ _null_ _null_ _null_ percentile_cont_float8_final _null_ _null_ _null_ ));
+DATA(insert OID = 3975 ( percentile_cont_float8_final	PGNSP PGUID 12 1 0 0 0 f f f f f f i 2 0 701 "2281 701" _null_ _null_ _null_ _null_ percentile_cont_float8_final _null_ _null_ _null_ ));
 DESCR("aggregate final function");
 DATA(insert OID = 3976 ( percentile_cont		PGNSP PGUID 12 1 0 0 0 t f f f f f i 2 0 1186 "701 1186" _null_ _null_ _null_ _null_ aggregate_dummy _null_ _null_ _null_ ));
 DESCR("continuous distribution percentile");
-DATA(insert OID = 3977 ( percentile_cont_interval_final PGNSP PGUID 12 1 0 0 0 f f f f f f i 3 0 1186 "2281 701 1186" _null_ _null_ _null_ _null_ percentile_cont_interval_final _null_ _null_ _null_ ));
+DATA(insert OID = 3977 ( percentile_cont_interval_final PGNSP PGUID 12 1 0 0 0 f f f f f f i 2 0 1186 "2281 701" _null_ _null_ _null_ _null_ percentile_cont_interval_final _null_ _null_ _null_ ));
 DESCR("aggregate final function");
 DATA(insert OID = 3978 ( percentile_disc		PGNSP PGUID 12 1 0 0 0 t f f f f f i 2 0 2277 "1022 2283" _null_ _null_ _null_ _null_ aggregate_dummy _null_ _null_ _null_ ));
 DESCR("multiple discrete percentiles");
@@ -5002,11 +5002,11 @@ DATA(insert OID = 3979 ( percentile_disc_multi_final	PGNSP PGUID 12 1 0 0 0 f f
 DESCR("aggregate final function");
 DATA(insert OID = 3980 ( percentile_cont		PGNSP PGUID 12 1 0 0 0 t f f f f f i 2 0 1022 "1022 701" _null_ _null_ _null_ _null_ aggregate_dummy _null_ _null_ _null_ ));
 DESCR("multiple continuous percentiles");
-DATA(insert OID = 3981 ( percentile_cont_float8_multi_final PGNSP PGUID 12 1 0 0 0 f f f f f f i 3 0 1022 "2281 1022 701" _null_ _null_ _null_ _null_ percentile_cont_float8_multi_final _null_ _null_ _null_ ));
+DATA(insert OID = 3981 ( percentile_cont_float8_multi_final PGNSP PGUID 12 1 0 0 0 f f f f f f i 2 0 1022 "2281 1022" _null_ _null_ _null_ _null_ percentile_cont_float8_multi_final _null_ _null_ _null_ ));
 DESCR("aggregate final function");
 DATA(insert OID = 3982 ( percentile_cont		PGNSP PGUID 12 1 0 0 0 t f f f f f i 2 0 1187 "1022 1186" _null_ _null_ _null_ _null_ aggregate_dummy _null_ _null_ _null_ ));
 DESCR("multiple continuous percentiles");
-DATA(insert OID = 3983 ( percentile_cont_interval_multi_final	PGNSP PGUID 12 1 0 0 0 f f f f f f i 3 0 1187 "2281 1022 1186" _null_ _null_ _null_ _null_ percentile_cont_interval_multi_final _null_ _null_ _null_ ));
+DATA(insert OID = 3983 ( percentile_cont_interval_multi_final	PGNSP PGUID 12 1 0 0 0 f f f f f f i 2 0 1187 "2281 1022" _null_ _null_ _null_ _null_ percentile_cont_interval_multi_final _null_ _null_ _null_ ));
 DESCR("aggregate final function");
 DATA(insert OID = 3984 ( mode					PGNSP PGUID 12 1 0 0 0 t f f f f f i 1 0 2283 "2283" _null_ _null_ _null_ _null_	aggregate_dummy _null_ _null_ _null_ ));
 DESCR("most common value");

src/include/parser/parse_agg.h

@@ -33,7 +33,7 @@ extern Oid resolve_aggregate_transtype(Oid aggfuncid,
 extern void build_aggregate_fnexprs(Oid *agg_input_types,
 						int agg_num_inputs,
 						int agg_num_direct_inputs,
-						bool agg_ordered_set,
+						int num_finalfn_inputs,
 						bool agg_variadic,
 						Oid agg_state_type,
 						Oid agg_result_type,

src/test/regress/expected/create_aggregate.out

@@ -70,12 +70,14 @@ create aggregate least_agg(variadic items anyarray) (
 create aggregate my_percentile_disc(float8 ORDER BY anyelement) (
   stype = internal,
   sfunc = ordered_set_transition,
-  finalfunc = percentile_disc_final
+  finalfunc = percentile_disc_final,
+  finalfunc_extra = true
 );
 create aggregate my_rank(VARIADIC "any" ORDER BY VARIADIC "any") (
   stype = internal,
   sfunc = ordered_set_transition_multi,
   finalfunc = rank_final,
+  finalfunc_extra = true,
   hypothetical
 );
 alter aggregate my_percentile_disc(float8 ORDER BY anyelement)

src/test/regress/expected/opr_sanity.out

@@ -283,6 +283,38 @@ WHERE p1.prorettype = 'internal'::regtype AND NOT
  2304 | internal_in
 (1 row)
 
+-- Look for functions that return a polymorphic type and do not have any
+-- polymorphic argument.  Calls of such functions would be unresolvable
+-- at parse time.  As of 9.4 this query should find only some input functions
+-- associated with these pseudotypes.
+SELECT p1.oid, p1.proname
+FROM pg_proc as p1
+WHERE p1.prorettype IN
+    ('anyelement'::regtype, 'anyarray'::regtype, 'anynonarray'::regtype,
+     'anyenum'::regtype, 'anyrange'::regtype)
+  AND NOT
+    ('anyelement'::regtype = ANY (p1.proargtypes) OR
+     'anyarray'::regtype = ANY (p1.proargtypes) OR
+     'anynonarray'::regtype = ANY (p1.proargtypes) OR
+     'anyenum'::regtype = ANY (p1.proargtypes) OR
+     'anyrange'::regtype = ANY (p1.proargtypes))
+ORDER BY 2;
+ oid  |    proname     
+------+----------------
+ 2296 | anyarray_in
+ 2502 | anyarray_recv
+ 2312 | anyelement_in
+ 3504 | anyenum_in
+ 2777 | anynonarray_in
+ 3832 | anyrange_in
+  750 | array_in
+ 2400 | array_recv
+ 3506 | enum_in
+ 3532 | enum_recv
+ 3834 | range_in
+ 3836 | range_recv
+(12 rows)
+
 -- Check for length inconsistencies between the various argument-info arrays.
 SELECT p1.oid, p1.proname
 FROM pg_proc as p1
@@ -800,16 +832,16 @@ WHERE a.aggfnoid = p.oid AND
     (pfn.proretset OR
      NOT binary_coercible(pfn.prorettype, p.prorettype) OR
      NOT binary_coercible(a.aggtranstype, pfn.proargtypes[0]) OR
-     CASE WHEN a.aggkind = 'n' THEN pfn.pronargs != 1
-     ELSE pfn.pronargs != p.pronargs + 1
-       OR (p.pronargs > 0 AND
+     CASE WHEN a.aggfinalextra THEN pfn.pronargs != p.pronargs + 1
+          ELSE pfn.pronargs != a.aggnumdirectargs + 1 END
+     OR (pfn.pronargs > 1 AND
          NOT binary_coercible(p.proargtypes[0], pfn.proargtypes[1]))
-       OR (p.pronargs > 1 AND
+     OR (pfn.pronargs > 2 AND
          NOT binary_coercible(p.proargtypes[1], pfn.proargtypes[2]))
-       OR (p.pronargs > 2 AND
+     OR (pfn.pronargs > 3 AND
          NOT binary_coercible(p.proargtypes[2], pfn.proargtypes[3]))
-       -- we could carry the check further, but 3 args is enough for now
-     END);
+     -- we could carry the check further, but 3 args is enough for now
+    );
  aggfnoid | proname | oid | proname 
 ----------+---------+-----+---------
 (0 rows)
@@ -909,16 +941,16 @@ WHERE a.aggfnoid = p.oid AND
     (pfn.proretset OR
      NOT binary_coercible(pfn.prorettype, p.prorettype) OR
      NOT binary_coercible(a.aggmtranstype, pfn.proargtypes[0]) OR
-     CASE WHEN a.aggkind = 'n' THEN pfn.pronargs != 1
-     ELSE pfn.pronargs != p.pronargs + 1
-       OR (p.pronargs > 0 AND
+     CASE WHEN a.aggmfinalextra THEN pfn.pronargs != p.pronargs + 1
+          ELSE pfn.pronargs != a.aggnumdirectargs + 1 END
+     OR (pfn.pronargs > 1 AND
          NOT binary_coercible(p.proargtypes[0], pfn.proargtypes[1]))
-       OR (p.pronargs > 1 AND
+     OR (pfn.pronargs > 2 AND
          NOT binary_coercible(p.proargtypes[1], pfn.proargtypes[2]))
-       OR (p.pronargs > 2 AND
+     OR (pfn.pronargs > 3 AND
          NOT binary_coercible(p.proargtypes[2], pfn.proargtypes[3]))
-       -- we could carry the check further, but 3 args is enough for now
-     END);
+     -- we could carry the check further, but 3 args is enough for now
+    );
  aggfnoid | proname | oid | proname 
 ----------+---------+-----+---------
 (0 rows)

src/test/regress/sql/create_aggregate.sql

@@ -85,13 +85,15 @@ create aggregate least_agg(variadic items anyarray) (
 create aggregate my_percentile_disc(float8 ORDER BY anyelement) (
   stype = internal,
   sfunc = ordered_set_transition,
-  finalfunc = percentile_disc_final
+  finalfunc = percentile_disc_final,
+  finalfunc_extra = true
 );
 
 create aggregate my_rank(VARIADIC "any" ORDER BY VARIADIC "any") (
   stype = internal,
   sfunc = ordered_set_transition_multi,
   finalfunc = rank_final,
+  finalfunc_extra = true,
   hypothetical
 );
 

src/test/regress/sql/opr_sanity.sql

@@ -226,6 +226,24 @@ FROM pg_proc as p1
 WHERE p1.prorettype = 'internal'::regtype AND NOT
     'internal'::regtype = ANY (p1.proargtypes);
 
+-- Look for functions that return a polymorphic type and do not have any
+-- polymorphic argument.  Calls of such functions would be unresolvable
+-- at parse time.  As of 9.4 this query should find only some input functions
+-- associated with these pseudotypes.
+
+SELECT p1.oid, p1.proname
+FROM pg_proc as p1
+WHERE p1.prorettype IN
+    ('anyelement'::regtype, 'anyarray'::regtype, 'anynonarray'::regtype,
+     'anyenum'::regtype, 'anyrange'::regtype)
+  AND NOT
+    ('anyelement'::regtype = ANY (p1.proargtypes) OR
+     'anyarray'::regtype = ANY (p1.proargtypes) OR
+     'anynonarray'::regtype = ANY (p1.proargtypes) OR
+     'anyenum'::regtype = ANY (p1.proargtypes) OR
+     'anyrange'::regtype = ANY (p1.proargtypes))
+ORDER BY 2;
+
 -- Check for length inconsistencies between the various argument-info arrays.
 
 SELECT p1.oid, p1.proname
@@ -646,16 +664,16 @@ WHERE a.aggfnoid = p.oid AND
     (pfn.proretset OR
      NOT binary_coercible(pfn.prorettype, p.prorettype) OR
      NOT binary_coercible(a.aggtranstype, pfn.proargtypes[0]) OR
-     CASE WHEN a.aggkind = 'n' THEN pfn.pronargs != 1
-     ELSE pfn.pronargs != p.pronargs + 1
-       OR (p.pronargs > 0 AND
+     CASE WHEN a.aggfinalextra THEN pfn.pronargs != p.pronargs + 1
+          ELSE pfn.pronargs != a.aggnumdirectargs + 1 END
+     OR (pfn.pronargs > 1 AND
          NOT binary_coercible(p.proargtypes[0], pfn.proargtypes[1]))
-       OR (p.pronargs > 1 AND
+     OR (pfn.pronargs > 2 AND
          NOT binary_coercible(p.proargtypes[1], pfn.proargtypes[2]))
-       OR (p.pronargs > 2 AND
+     OR (pfn.pronargs > 3 AND
          NOT binary_coercible(p.proargtypes[2], pfn.proargtypes[3]))
-       -- we could carry the check further, but 3 args is enough for now
-     END);
+     -- we could carry the check further, but 3 args is enough for now
+    );
 
 -- If transfn is strict then either initval should be non-NULL, or
 -- input type should match transtype so that the first non-null input
@@ -738,16 +756,16 @@ WHERE a.aggfnoid = p.oid AND
     (pfn.proretset OR
      NOT binary_coercible(pfn.prorettype, p.prorettype) OR
      NOT binary_coercible(a.aggmtranstype, pfn.proargtypes[0]) OR
-     CASE WHEN a.aggkind = 'n' THEN pfn.pronargs != 1
-     ELSE pfn.pronargs != p.pronargs + 1
-       OR (p.pronargs > 0 AND
+     CASE WHEN a.aggmfinalextra THEN pfn.pronargs != p.pronargs + 1
+          ELSE pfn.pronargs != a.aggnumdirectargs + 1 END
+     OR (pfn.pronargs > 1 AND
          NOT binary_coercible(p.proargtypes[0], pfn.proargtypes[1]))
-       OR (p.pronargs > 1 AND
+     OR (pfn.pronargs > 2 AND
          NOT binary_coercible(p.proargtypes[1], pfn.proargtypes[2]))
-       OR (p.pronargs > 2 AND
+     OR (pfn.pronargs > 3 AND
          NOT binary_coercible(p.proargtypes[2], pfn.proargtypes[3]))
-       -- we could carry the check further, but 3 args is enough for now
-     END);
+     -- we could carry the check further, but 3 args is enough for now
+    );
 
 -- If mtransfn is strict then either minitval should be non-NULL, or
 -- input type should match mtranstype so that the first non-null input