3 files changed, 45 insertions, 3 deletions

diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 94006c1189..c3a53d81aa 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -2109,7 +2109,8 @@ ChooseIndexName(const char *tabname, Oid namespaceId,
  * We know that less than NAMEDATALEN characters will actually be used,
  * so we can truncate the result once we've generated that many.
  *
- * XXX See also ChooseExtendedStatisticNameAddition.
+ * XXX See also ChooseForeignKeyConstraintNameAddition and
+ * ChooseExtendedStatisticNameAddition.
  */
 static char *
 ChooseIndexNameAddition(List *colnames)
diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index 50762e2d51..8274792a77 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -498,7 +498,8 @@ ChooseExtendedStatisticName(const char *name1, const char *name2,
  * We know that less than NAMEDATALEN characters will actually be used,
  * so we can truncate the result once we've generated that many.
  *
- * XXX see also ChooseIndexNameAddition.
+ * XXX see also ChooseForeignKeyConstraintNameAddition and
+ * ChooseIndexNameAddition.
  */
 static char *
 ChooseExtendedStatisticNameAddition(List *exprs)
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 754b59581b..515c29072c 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -402,6 +402,7 @@ static ObjectAddress ATExecAddConstraint(List **wqueue,
 					AlteredTableInfo *tab, Relation rel,
 					Constraint *newConstraint, bool recurse, bool is_readd,
 					LOCKMODE lockmode);
+static char *ChooseForeignKeyConstraintNameAddition(List *colnames);
 static ObjectAddress ATExecAddIndexConstraint(AlteredTableInfo *tab, Relation rel,
 						 IndexStmt *stmt, LOCKMODE lockmode);
 static ObjectAddress ATAddCheckConstraint(List **wqueue,
@@ -7191,7 +7192,7 @@ ATExecAddConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			else
 				newConstraint->conname =
 					ChooseConstraintName(RelationGetRelationName(rel),
-										 strVal(linitial(newConstraint->fk_attrs)),
+										 ChooseForeignKeyConstraintNameAddition(newConstraint->fk_attrs),
 										 "fkey",
 										 RelationGetNamespace(rel),
 										 NIL);
@@ -7211,6 +7212,45 @@ ATExecAddConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 }
 
 /*
+ * Generate the column-name portion of the constraint name for a new foreign
+ * key given the list of column names that reference the referenced
+ * table.  This will be passed to ChooseConstraintName along with the parent
+ * table name and the "fkey" suffix.
+ *
+ * We know that less than NAMEDATALEN characters will actually be used, so we
+ * can truncate the result once we've generated that many.
+ *
+ * XXX see also ChooseExtendedStatisticNameAddition and
+ * ChooseIndexNameAddition.
+ */
+static char *
+ChooseForeignKeyConstraintNameAddition(List *colnames)
+{
+	char		buf[NAMEDATALEN * 2];
+	int			buflen = 0;
+	ListCell   *lc;
+
+	buf[0] = '\0';
+	foreach(lc, colnames)
+	{
+		const char *name = strVal(lfirst(lc));
+
+		if (buflen > 0)
+			buf[buflen++] = '_';	/* insert _ between names */
+
+		/*
+		 * At this point we have buflen <= NAMEDATALEN.  name should be less
+		 * than NAMEDATALEN already, but use strlcpy for paranoia.
+		 */
+		strlcpy(buf + buflen, name, NAMEDATALEN);
+		buflen += strlen(buf + buflen);
+		if (buflen >= NAMEDATALEN)
+			break;
+	}
+	return pstrdup(buf);
+}
+
+/*
  * Add a check constraint to a single table and its children.  Returns the
  * address of the constraint added to the parent relation, if one gets added,
  * or InvalidObjectAddress otherwise.