Remove unnecessary coziness of GIN code with datum copying. Now that

space is tracked via GetMemoryChunkSpace, there's really no advantage
to duplicating datumCopy's innards here.  This is one bit of my toast
indirection patch that should go in anyway.

src/backend/access/gin/ginbulk.c

@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *			$PostgreSQL: pgsql/src/backend/access/gin/ginbulk.c,v 1.11 2008/01/01 19:45:46 momjian Exp $
+ *			$PostgreSQL: pgsql/src/backend/access/gin/ginbulk.c,v 1.12 2008/06/29 21:04:01 tgl Exp $
  *-------------------------------------------------------------------------
  */
 
@@ -78,8 +78,8 @@ ginInsertData(BuildAccumulator *accum, EntryAccumulator *entry, ItemPointer heap
 }
 
 /*
- * This is basically the same as datumCopy(), but we duplicate some code
- * to avoid computing the datum size twice.
+ * This is basically the same as datumCopy(), but modified to count
+ * palloc'd space in accum.
  */
 static Datum
 getDatumCopy(BuildAccumulator *accum, Datum value)
@@ -91,16 +91,8 @@ getDatumCopy(BuildAccumulator *accum, Datum value)
 		res = value;
 	else
 	{
-		Size		realSize;
-		char	   *s;
-
-		realSize = datumGetSize(value, false, att[0]->attlen);
-
-		s = (char *) palloc(realSize);
-		accum->allocatedMemory += GetMemoryChunkSpace(s);
-
-		memcpy(s, DatumGetPointer(value), realSize);
-		res = PointerGetDatum(s);
+		res = datumCopy(value, false, att[0]->attlen);
+		accum->allocatedMemory += GetMemoryChunkSpace(DatumGetPointer(res));
 	}
 	return res;
 }