Refactor attribute mappings used in logical tuple conversion

Tuple conversion support in tupconvert.c is able to convert rowtypes
between two relations, inner and outer, which are logically equivalent
but have a different ordering or even dropped columns (used mainly for
inheritance tree and partitions).  This makes use of attribute mappings,
which are simple arrays made of AttrNumber elements with a length
matching the number of attributes of the outer relation.  The length of
the attribute mapping has been treated as completely independent of the
mapping itself until now, making it easy to pass down an incorrect
mapping length.

This commit refactors the code related to attribute mappings and moves
it into an independent facility called attmap.c, extracted from
tupconvert.c.  This merges the attribute mapping with its length,
avoiding to try to guess what is the length of a mapping to use as this
is computed once, when the map is built.

This will avoid mistakes like what has been fixed in dc816e58, which has
used an incorrect mapping length by matching it with the number of
attributes of an inner relation (a child partition) instead of an outer
relation (a partitioned table).

Author: Michael Paquier
Reviewed-by: Amit Langote
Discussion: https://postgr.es/m/20191121042556.GD153437@paquier.xyz

3 files changed, 341 insertions, 267 deletions

diff --git a/src/backend/access/common/Makefile b/src/backend/access/common/Makefile
index 6c9c6f32565..fd74e14024c 100644
--- a/src/backend/access/common/Makefile
+++ b/src/backend/access/common/Makefile
@@ -13,6 +13,7 @@ top_builddir = ../../../..
 include $(top_builddir)/src/Makefile.global
 
 OBJS = \
+	attmap.o \
 	bufmask.o \
 	detoast.o \
 	heaptuple.o \
diff --git a/src/backend/access/common/attmap.c b/src/backend/access/common/attmap.c
new file mode 100644
index 00000000000..ba909b0d4e7
--- /dev/null
+++ b/src/backend/access/common/attmap.c
@@ -0,0 +1,320 @@
+/*-------------------------------------------------------------------------
+ *
+ * attmap.c
+ *	  Attribute mapping support.
+ *
+ * This file provides utility routines to build and manage attribute
+ * mappings by comparing input and output TupleDescs.  Such mappings
+ * are typically used by DDL operating on inheritance and partition trees
+ * to do a conversion between rowtypes logically equivalent but with
+ * columns in a different order, taking into account dropped columns.
+ * They are also used by the tuple conversion routines in tupconvert.c.
+ *
+ * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *	  src/backend/access/common/attmap.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/attmap.h"
+#include "access/htup_details.h"
+#include "utils/builtins.h"
+
+
+static bool check_attrmap_match(TupleDesc indesc,
+								TupleDesc outdesc,
+								AttrMap *attrMap);
+
+/*
+ * make_attrmap
+ *
+ * Utility routine to allocate an attribute map in the current memory
+ * context.
+ */
+AttrMap *
+make_attrmap(int maplen)
+{
+	AttrMap    *res;
+
+	res = (AttrMap *) palloc0(sizeof(AttrMap));
+	res->maplen = maplen;
+	res->attnums = (AttrNumber *) palloc0(sizeof(AttrNumber) * maplen);
+	return res;
+}
+
+/*
+ * free_attrmap
+ *
+ * Utility routine to release an attribute map.
+ */
+void
+free_attrmap(AttrMap *map)
+{
+	pfree(map->attnums);
+	pfree(map);
+}
+
+/*
+ * build_attrmap_by_position
+ *
+ * Return a palloc'd bare attribute map for tuple conversion, matching input
+ * and output columns by position.  Dropped columns are ignored in both input
+ * and output, marked as 0.  This is normally a subroutine for
+ * convert_tuples_by_position in tupconvert.c, but it can be used standalone.
+ *
+ * Note: the errdetail messages speak of indesc as the "returned" rowtype,
+ * outdesc as the "expected" rowtype.  This is okay for current uses but
+ * might need generalization in future.
+ */
+AttrMap *
+build_attrmap_by_position(TupleDesc indesc,
+						  TupleDesc outdesc,
+						  const char *msg)
+{
+	AttrMap    *attrMap;
+	int			nincols;
+	int			noutcols;
+	int			n;
+	int			i;
+	int			j;
+	bool		same;
+
+	/*
+	 * The length is computed as the number of attributes of the expected
+	 * rowtype as it includes dropped attributes in its count.
+	 */
+	n = outdesc->natts;
+	attrMap = make_attrmap(n);
+
+	j = 0;						/* j is next physical input attribute */
+	nincols = noutcols = 0;		/* these count non-dropped attributes */
+	same = true;
+	for (i = 0; i < n; i++)
+	{
+		Form_pg_attribute att = TupleDescAttr(outdesc, i);
+		Oid			atttypid;
+		int32		atttypmod;
+
+		if (att->attisdropped)
+			continue;			/* attrMap->attnums[i] is already 0 */
+		noutcols++;
+		atttypid = att->atttypid;
+		atttypmod = att->atttypmod;
+		for (; j < indesc->natts; j++)
+		{
+			att = TupleDescAttr(indesc, j);
+			if (att->attisdropped)
+				continue;
+			nincols++;
+
+			/* Found matching column, now check type */
+			if (atttypid != att->atttypid ||
+				(atttypmod != att->atttypmod && atttypmod >= 0))
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg_internal("%s", _(msg)),
+						 errdetail("Returned type %s does not match expected type %s in column %d.",
+								   format_type_with_typemod(att->atttypid,
+															att->atttypmod),
+								   format_type_with_typemod(atttypid,
+															atttypmod),
+								   noutcols)));
+			attrMap->attnums[i] = (AttrNumber) (j + 1);
+			j++;
+			break;
+		}
+		if (attrMap->attnums[i] == 0)
+			same = false;		/* we'll complain below */
+	}
+
+	/* Check for unused input columns */
+	for (; j < indesc->natts; j++)
+	{
+		if (TupleDescAttr(indesc, j)->attisdropped)
+			continue;
+		nincols++;
+		same = false;			/* we'll complain below */
+	}
+
+	/* Report column count mismatch using the non-dropped-column counts */
+	if (!same)
+		ereport(ERROR,
+				(errcode(ERRCODE_DATATYPE_MISMATCH),
+				 errmsg_internal("%s", _(msg)),
+				 errdetail("Number of returned columns (%d) does not match "
+						   "expected column count (%d).",
+						   nincols, noutcols)));
+
+	/* Check if the map has a one-to-one match */
+	if (check_attrmap_match(indesc, outdesc, attrMap))
+	{
+		/* Runtime conversion is not needed */
+		free_attrmap(attrMap);
+		return NULL;
+	}
+
+	return attrMap;
+}
+
+/*
+ * build_attrmap_by_name
+ *
+ * Return a palloc'd bare attribute map for tuple conversion, matching input
+ * and output columns by name.  (Dropped columns are ignored in both input and
+ * output.)  This is normally a subroutine for convert_tuples_by_name in
+ * tupconvert.c, but can be used standalone.
+ */
+AttrMap *
+build_attrmap_by_name(TupleDesc indesc,
+					  TupleDesc outdesc)
+{
+	AttrMap    *attrMap;
+	int			outnatts;
+	int			innatts;
+	int			i;
+	int			nextindesc = -1;
+
+	outnatts = outdesc->natts;
+	innatts = indesc->natts;
+
+	attrMap = make_attrmap(outnatts);
+	for (i = 0; i < outnatts; i++)
+	{
+		Form_pg_attribute outatt = TupleDescAttr(outdesc, i);
+		char	   *attname;
+		Oid			atttypid;
+		int32		atttypmod;
+		int			j;
+
+		if (outatt->attisdropped)
+			continue;			/* attrMap->attnums[i] is already 0 */
+		attname = NameStr(outatt->attname);
+		atttypid = outatt->atttypid;
+		atttypmod = outatt->atttypmod;
+
+		/*
+		 * Now search for an attribute with the same name in the indesc. It
+		 * seems likely that a partitioned table will have the attributes in
+		 * the same order as the partition, so the search below is optimized
+		 * for that case.  It is possible that columns are dropped in one of
+		 * the relations, but not the other, so we use the 'nextindesc'
+		 * counter to track the starting point of the search.  If the inner
+		 * loop encounters dropped columns then it will have to skip over
+		 * them, but it should leave 'nextindesc' at the correct position for
+		 * the next outer loop.
+		 */
+		for (j = 0; j < innatts; j++)
+		{
+			Form_pg_attribute inatt;
+
+			nextindesc++;
+			if (nextindesc >= innatts)
+				nextindesc = 0;
+
+			inatt = TupleDescAttr(indesc, nextindesc);
+			if (inatt->attisdropped)
+				continue;
+			if (strcmp(attname, NameStr(inatt->attname)) == 0)
+			{
+				/* Found it, check type */
+				if (atttypid != inatt->atttypid || atttypmod != inatt->atttypmod)
+					ereport(ERROR,
+							(errcode(ERRCODE_DATATYPE_MISMATCH),
+							 errmsg("could not convert row type"),
+							 errdetail("Attribute \"%s\" of type %s does not match corresponding attribute of type %s.",
+									   attname,
+									   format_type_be(outdesc->tdtypeid),
+									   format_type_be(indesc->tdtypeid))));
+				attrMap->attnums[i] = inatt->attnum;
+				break;
+			}
+		}
+		if (attrMap->attnums[i] == 0)
+			ereport(ERROR,
+					(errcode(ERRCODE_DATATYPE_MISMATCH),
+					 errmsg("could not convert row type"),
+					 errdetail("Attribute \"%s\" of type %s does not exist in type %s.",
+							   attname,
+							   format_type_be(outdesc->tdtypeid),
+							   format_type_be(indesc->tdtypeid))));
+	}
+	return attrMap;
+}
+
+/*
+ * build_attrmap_by_name_if_req
+ *
+ * Returns mapping created by build_attrmap_by_name, or NULL if no
+ * conversion is required.  This is a convenience routine for
+ * convert_tuples_by_name() in tupconvert.c and other functions, but it
+ * can be used standalone.
+ */
+AttrMap *
+build_attrmap_by_name_if_req(TupleDesc indesc,
+							 TupleDesc outdesc)
+{
+	AttrMap    *attrMap;
+
+	/* Verify compatibility and prepare attribute-number map */
+	attrMap = build_attrmap_by_name(indesc, outdesc);
+
+	/* Check if the map has a one-to-one match */
+	if (check_attrmap_match(indesc, outdesc, attrMap))
+	{
+		/* Runtime conversion is not needed */
+		free_attrmap(attrMap);
+		return NULL;
+	}
+
+	return attrMap;
+}
+
+/*
+ * check_attrmap_match
+ *
+ * Check to see if the map is a one-to-one match, in which case we need
+ * not to do a tuple conversion, and the attribute map is not necessary.
+ */
+static bool
+check_attrmap_match(TupleDesc indesc,
+					TupleDesc outdesc,
+					AttrMap *attrMap)
+{
+	int			i;
+
+	/* no match if attribute numbers are not the same */
+	if (indesc->natts != outdesc->natts)
+		return false;
+
+	for (i = 0; i < attrMap->maplen; i++)
+	{
+		Form_pg_attribute inatt;
+		Form_pg_attribute outatt;
+
+		if (attrMap->attnums[i] == (i + 1))
+			continue;
+
+		/*
+		 * If it's a dropped column and the corresponding input column is also
+		 * dropped, we don't need a conversion.  However, attlen and attalign
+		 * must agree.
+		 */
+		inatt = TupleDescAttr(indesc, i);
+		outatt = TupleDescAttr(outdesc, i);
+		if (attrMap->attnums[i] == 0 &&
+			inatt->attisdropped &&
+			inatt->attlen == outatt->attlen &&
+			inatt->attalign == outatt->attalign)
+			continue;
+
+		return false;
+	}
+
+	return true;
+}
diff --git a/src/backend/access/common/tupconvert.c b/src/backend/access/common/tupconvert.c
index 0ec9cd5870d..85b194f3944 100644
--- a/src/backend/access/common/tupconvert.c
+++ b/src/backend/access/common/tupconvert.c
@@ -18,20 +18,18 @@
  */
 #include "postgres.h"
 
-#include "access/htup_details.h"
 #include "access/tupconvert.h"
 #include "executor/tuptable.h"
-#include "utils/builtins.h"
 
 
 /*
  * The conversion setup routines have the following common API:
  *
- * The setup routine checks whether the given source and destination tuple
- * descriptors are logically compatible.  If not, it throws an error.
- * If so, it returns NULL if they are physically compatible (ie, no conversion
- * is needed), else a TupleConversionMap that can be used by execute_attr_map_tuple
- * to perform the conversion.
+ * The setup routine checks using attmap.c whether the given source and
+ * destination tuple descriptors are logically compatible.  If not, it throws
+ * an error.  If so, it returns NULL if they are physically compatible (ie, no
+ * conversion is needed), else a TupleConversionMap that can be used by
+ * execute_attr_map_tuple or execute_attr_map_slot to perform the conversion.
  *
  * The TupleConversionMap, if needed, is palloc'd in the caller's memory
  * context.  Also, the given tuple descriptors are referenced by the map,
@@ -56,10 +54,6 @@
 /*
  * Set up for tuple conversion, matching input and output columns by
  * position.  (Dropped columns are ignored in both input and output.)
- *
- * Note: the errdetail messages speak of indesc as the "returned" rowtype,
- * outdesc as the "expected" rowtype.  This is okay for current uses but
- * might need generalization in future.
  */
 TupleConversionMap *
 convert_tuples_by_position(TupleDesc indesc,
@@ -67,113 +61,15 @@ convert_tuples_by_position(TupleDesc indesc,
 						   const char *msg)
 {
 	TupleConversionMap *map;
-	AttrNumber *attrMap;
-	int			nincols;
-	int			noutcols;
 	int			n;
-	int			i;
-	int			j;
-	bool		same;
+	AttrMap    *attrMap;
 
 	/* Verify compatibility and prepare attribute-number map */
-	n = outdesc->natts;
-	attrMap = (AttrNumber *) palloc0(n * sizeof(AttrNumber));
-	j = 0;						/* j is next physical input attribute */
-	nincols = noutcols = 0;		/* these count non-dropped attributes */
-	same = true;
-	for (i = 0; i < n; i++)
-	{
-		Form_pg_attribute att = TupleDescAttr(outdesc, i);
-		Oid			atttypid;
-		int32		atttypmod;
-
-		if (att->attisdropped)
-			continue;			/* attrMap[i] is already 0 */
-		noutcols++;
-		atttypid = att->atttypid;
-		atttypmod = att->atttypmod;
-		for (; j < indesc->natts; j++)
-		{
-			att = TupleDescAttr(indesc, j);
-			if (att->attisdropped)
-				continue;
-			nincols++;
-			/* Found matching column, check type */
-			if (atttypid != att->atttypid ||
-				(atttypmod != att->atttypmod && atttypmod >= 0))
-				ereport(ERROR,
-						(errcode(ERRCODE_DATATYPE_MISMATCH),
-						 errmsg_internal("%s", _(msg)),
-						 errdetail("Returned type %s does not match expected type %s in column %d.",
-								   format_type_with_typemod(att->atttypid,
-															att->atttypmod),
-								   format_type_with_typemod(atttypid,
-															atttypmod),
-								   noutcols)));
-			attrMap[i] = (AttrNumber) (j + 1);
-			j++;
-			break;
-		}
-		if (attrMap[i] == 0)
-			same = false;		/* we'll complain below */
-	}
-
-	/* Check for unused input columns */
-	for (; j < indesc->natts; j++)
-	{
-		if (TupleDescAttr(indesc, j)->attisdropped)
-			continue;
-		nincols++;
-		same = false;			/* we'll complain below */
-	}
-
-	/* Report column count mismatch using the non-dropped-column counts */
-	if (!same)
-		ereport(ERROR,
-				(errcode(ERRCODE_DATATYPE_MISMATCH),
-				 errmsg_internal("%s", _(msg)),
-				 errdetail("Number of returned columns (%d) does not match "
-						   "expected column count (%d).",
-						   nincols, noutcols)));
-
-	/*
-	 * Check to see if the map is one-to-one, in which case we need not do a
-	 * tuple conversion.
-	 */
-	if (indesc->natts == outdesc->natts)
-	{
-		for (i = 0; i < n; i++)
-		{
-			Form_pg_attribute inatt;
-			Form_pg_attribute outatt;
-
-			if (attrMap[i] == (i + 1))
-				continue;
+	attrMap = build_attrmap_by_position(indesc, outdesc, msg);
 
-			/*
-			 * If it's a dropped column and the corresponding input column is
-			 * also dropped, we needn't convert.  However, attlen and attalign
-			 * must agree.
-			 */
-			inatt = TupleDescAttr(indesc, i);
-			outatt = TupleDescAttr(outdesc, i);
-			if (attrMap[i] == 0 &&
-				inatt->attisdropped &&
-				inatt->attlen == outatt->attlen &&
-				inatt->attalign == outatt->attalign)
-				continue;
-
-			same = false;
-			break;
-		}
-	}
-	else
-		same = false;
-
-	if (same)
+	if (attrMap == NULL)
 	{
-		/* Runtime conversion is not needed */
-		pfree(attrMap);
+		/* runtime conversion is not needed */
 		return NULL;
 	}
 
@@ -183,6 +79,7 @@ convert_tuples_by_position(TupleDesc indesc,
 	map->outdesc = outdesc;
 	map->attrMap = attrMap;
 	/* preallocate workspace for Datum arrays */
+	n = outdesc->natts + 1;		/* +1 for NULL */
 	map->outvalues = (Datum *) palloc(n * sizeof(Datum));
 	map->outisnull = (bool *) palloc(n * sizeof(bool));
 	n = indesc->natts + 1;		/* +1 for NULL */
@@ -206,11 +103,11 @@ convert_tuples_by_name(TupleDesc indesc,
 					   TupleDesc outdesc)
 {
 	TupleConversionMap *map;
-	AttrNumber *attrMap;
+	AttrMap    *attrMap;
 	int			n = outdesc->natts;
 
 	/* Verify compatibility and prepare attribute-number map */
-	attrMap = convert_tuples_by_name_map_if_req(indesc, outdesc);
+	attrMap = build_attrmap_by_name_if_req(indesc, outdesc);
 
 	if (attrMap == NULL)
 	{
@@ -236,157 +133,12 @@ convert_tuples_by_name(TupleDesc indesc,
 }
 
 /*
- * Return a palloc'd bare attribute map for tuple conversion, matching input
- * and output columns by name.  (Dropped columns are ignored in both input and
- * output.)  This is normally a subroutine for convert_tuples_by_name, but can
- * be used standalone.
- */
-AttrNumber *
-convert_tuples_by_name_map(TupleDesc indesc,
-						   TupleDesc outdesc)
-{
-	AttrNumber *attrMap;
-	int			outnatts;
-	int			innatts;
-	int			i;
-	int			nextindesc = -1;
-
-	outnatts = outdesc->natts;
-	innatts = indesc->natts;
-
-	attrMap = (AttrNumber *) palloc0(outnatts * sizeof(AttrNumber));
-	for (i = 0; i < outnatts; i++)
-	{
-		Form_pg_attribute outatt = TupleDescAttr(outdesc, i);
-		char	   *attname;
-		Oid			atttypid;
-		int32		atttypmod;
-		int			j;
-
-		if (outatt->attisdropped)
-			continue;			/* attrMap[i] is already 0 */
-		attname = NameStr(outatt->attname);
-		atttypid = outatt->atttypid;
-		atttypmod = outatt->atttypmod;
-
-		/*
-		 * Now search for an attribute with the same name in the indesc. It
-		 * seems likely that a partitioned table will have the attributes in
-		 * the same order as the partition, so the search below is optimized
-		 * for that case.  It is possible that columns are dropped in one of
-		 * the relations, but not the other, so we use the 'nextindesc'
-		 * counter to track the starting point of the search.  If the inner
-		 * loop encounters dropped columns then it will have to skip over
-		 * them, but it should leave 'nextindesc' at the correct position for
-		 * the next outer loop.
-		 */
-		for (j = 0; j < innatts; j++)
-		{
-			Form_pg_attribute inatt;
-
-			nextindesc++;
-			if (nextindesc >= innatts)
-				nextindesc = 0;
-
-			inatt = TupleDescAttr(indesc, nextindesc);
-			if (inatt->attisdropped)
-				continue;
-			if (strcmp(attname, NameStr(inatt->attname)) == 0)
-			{
-				/* Found it, check type */
-				if (atttypid != inatt->atttypid || atttypmod != inatt->atttypmod)
-					ereport(ERROR,
-							(errcode(ERRCODE_DATATYPE_MISMATCH),
-							 errmsg("could not convert row type"),
-							 errdetail("Attribute \"%s\" of type %s does not match corresponding attribute of type %s.",
-									   attname,
-									   format_type_be(outdesc->tdtypeid),
-									   format_type_be(indesc->tdtypeid))));
-				attrMap[i] = inatt->attnum;
-				break;
-			}
-		}
-		if (attrMap[i] == 0)
-			ereport(ERROR,
-					(errcode(ERRCODE_DATATYPE_MISMATCH),
-					 errmsg("could not convert row type"),
-					 errdetail("Attribute \"%s\" of type %s does not exist in type %s.",
-							   attname,
-							   format_type_be(outdesc->tdtypeid),
-							   format_type_be(indesc->tdtypeid))));
-	}
-	return attrMap;
-}
-
-/*
- * Returns mapping created by convert_tuples_by_name_map, or NULL if no
- * conversion not required. This is a convenience routine for
- * convert_tuples_by_name() and other functions.
- */
-AttrNumber *
-convert_tuples_by_name_map_if_req(TupleDesc indesc,
-								  TupleDesc outdesc)
-{
-	AttrNumber *attrMap;
-	int			n = outdesc->natts;
-	int			i;
-	bool		same;
-
-	/* Verify compatibility and prepare attribute-number map */
-	attrMap = convert_tuples_by_name_map(indesc, outdesc);
-
-	/*
-	 * Check to see if the map is one-to-one, in which case we need not do a
-	 * tuple conversion.
-	 */
-	if (indesc->natts == outdesc->natts)
-	{
-		same = true;
-		for (i = 0; i < n; i++)
-		{
-			Form_pg_attribute inatt;
-			Form_pg_attribute outatt;
-
-			if (attrMap[i] == (i + 1))
-				continue;
-
-			/*
-			 * If it's a dropped column and the corresponding input column is
-			 * also dropped, we needn't convert.  However, attlen and attalign
-			 * must agree.
-			 */
-			inatt = TupleDescAttr(indesc, i);
-			outatt = TupleDescAttr(outdesc, i);
-			if (attrMap[i] == 0 &&
-				inatt->attisdropped &&
-				inatt->attlen == outatt->attlen &&
-				inatt->attalign == outatt->attalign)
-				continue;
-
-			same = false;
-			break;
-		}
-	}
-	else
-		same = false;
-
-	if (same)
-	{
-		/* Runtime conversion is not needed */
-		pfree(attrMap);
-		return NULL;
-	}
-	else
-		return attrMap;
-}
-
-/*
  * Perform conversion of a tuple according to the map.
  */
 HeapTuple
 execute_attr_map_tuple(HeapTuple tuple, TupleConversionMap *map)
 {
-	AttrNumber *attrMap = map->attrMap;
+	AttrMap    *attrMap = map->attrMap;
 	Datum	   *invalues = map->invalues;
 	bool	   *inisnull = map->inisnull;
 	Datum	   *outvalues = map->outvalues;
@@ -404,9 +156,10 @@ execute_attr_map_tuple(HeapTuple tuple, TupleConversionMap *map)
 	/*
 	 * Transpose into proper fields of the new tuple.
 	 */
-	for (i = 0; i < outnatts; i++)
+	Assert(attrMap->maplen == outnatts);
+	for (i = 0; i < attrMap->maplen; i++)
 	{
-		int			j = attrMap[i];
+		int			j = attrMap->attnums[i];
 
 		outvalues[i] = invalues[j];
 		outisnull[i] = inisnull[j];
@@ -422,7 +175,7 @@ execute_attr_map_tuple(HeapTuple tuple, TupleConversionMap *map)
  * Perform conversion of a tuple slot according to the map.
  */
 TupleTableSlot *
-execute_attr_map_slot(AttrNumber *attrMap,
+execute_attr_map_slot(AttrMap *attrMap,
 					  TupleTableSlot *in_slot,
 					  TupleTableSlot *out_slot)
 {
@@ -454,9 +207,9 @@ execute_attr_map_slot(AttrNumber *attrMap,
 	/* Transpose into proper fields of the out slot. */
 	for (i = 0; i < outnatts; i++)
 	{
-		int			j = attrMap[i] - 1;
+		int			j = attrMap->attnums[i] - 1;
 
-		/* attrMap[i] == 0 means it's a NULL datum. */
+		/* attrMap->attnums[i] == 0 means it's a NULL datum. */
 		if (j == -1)
 		{
 			outvalues[i] = (Datum) 0;
@@ -481,7 +234,7 @@ void
 free_conversion_map(TupleConversionMap *map)
 {
 	/* indesc and outdesc are not ours to free */
-	pfree(map->attrMap);
+	free_attrmap(map->attrMap);
 	pfree(map->invalues);
 	pfree(map->inisnull);
 	pfree(map->outvalues);