Fix tuptoaster bugs induced by making bytea toastable. Durn thing was

trying to toast tuples inserted into toast tables!  Fix is two-pronged:
first, ensure all columns of a toast table are marked attstorage='p',
and second, alter the target chunk size so that it's less than the
threshold for trying to toast a tuple.  (Code tried to do that but the
expression was wrong.)  A few cosmetic cleanups in tuptoaster too.
NOTE: initdb forced due to change in toaster chunk-size.

1 files changed, 42 insertions, 10 deletions

diff --git a/src/include/access/tuptoaster.h b/src/include/access/tuptoaster.h
index 91149f5f836..23f31aec522 100644
--- a/src/include/access/tuptoaster.h
+++ b/src/include/access/tuptoaster.h
@@ -6,7 +6,7 @@
  *
  * Copyright (c) 2000, PostgreSQL Development Team
  *
- * $Id: tuptoaster.h,v 1.7 2000/07/22 11:18:47 wieck Exp $
+ * $Id: tuptoaster.h,v 1.8 2000/08/04 04:16:10 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -20,25 +20,57 @@
 #include "access/tupmacs.h"
 #include "utils/rel.h"
 
+
+/*
+ * This enables de-toasting of index entries.  Needed until VACUUM is
+ * smart enough to rebuild indexes from scratch.
+ */
 #define TOAST_INDEX_HACK
 
 
-#define	TOAST_MAX_CHUNK_SIZE	((MaxTupleSize -							\
-				MAXALIGN(												\
-					MAXALIGN(offsetof(HeapTupleHeaderData, t_bits)) +	\
-					MAXALIGN(sizeof(Oid)) +								\
-					MAXALIGN(sizeof(int32)) +							\
-					MAXALIGN(VARHDRSZ))) / 4)
+/*
+ * These symbols control toaster activation.  If a tuple is larger than
+ * TOAST_TUPLE_THRESHOLD, we will try to toast it down to no more than
+ * TOAST_TUPLE_TARGET bytes.  Both numbers include all tuple header and
+ * alignment-padding overhead.
+ *
+ * The numbers need not be the same, though they currently are.
+ */
+#define TOAST_TUPLE_THRESHOLD	(MaxTupleSize / 4)
+
+#define TOAST_TUPLE_TARGET		(MaxTupleSize / 4)
+
+
+/*
+ * When we store an oversize datum externally, we divide it into chunks
+ * containing at most TOAST_MAX_CHUNK_SIZE data bytes.  This number *must*
+ * be small enough that the completed toast-table tuple (including the
+ * ID and sequence fields and all overhead) is no more than MaxTupleSize
+ * bytes.  It *should* be small enough to make toast-table tuples no more
+ * than TOAST_TUPLE_THRESHOLD bytes, else heapam.c will uselessly invoke
+ * the toaster on toast-table tuples.
+ *
+ * NB: you cannot change this value without forcing initdb, at least not
+ * if your DB contains any multi-chunk toasted values.
+ */
+#define TOAST_MAX_CHUNK_SIZE	(TOAST_TUPLE_THRESHOLD -			\
+			MAXALIGN(												\
+				MAXALIGN(offsetof(HeapTupleHeaderData, t_bits)) +	\
+				sizeof(Oid) +										\
+				sizeof(int32) +										\
+				VARHDRSZ))
 
 
 /* ----------
  * heap_tuple_toast_attrs() -
  *
  *		Called by heap_insert(), heap_update() and heap_delete().
- *		Outdates not any longer needed toast entries referenced
- *		by oldtup and creates new ones until newtup is smaller
- *		that ~2K (or running out of toastable values).
+ *		Outdates any no-longer-needed toast entries referenced
+ *		by oldtup and creates new ones until newtup is no more than
+ *		TOAST_TUPLE_TARGET (or we run out of toastable values).
  *		Possibly modifies newtup by replacing the t_data part!
+ *
+ *		oldtup is NULL if insert, newtup is NULL if delete.
  * ----------
  */
 extern void heap_tuple_toast_attrs(Relation rel,