Add hints to cases where indexes fail because of values that are too long.

src/backend/access/hash/hashinsert.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/hash/hashinsert.c,v 1.36 2005/03/21 01:23:57 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/hash/hashinsert.c,v 1.37 2005/08/10 21:36:45 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -88,7 +88,8 @@ _hash_doinsert(Relation rel, HashItem hitem)
 				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
 				 errmsg("index row size %lu exceeds hash maximum %lu",
 						(unsigned long) itemsz,
-						(unsigned long) HashMaxItemSize((Page) metap))));
+						(unsigned long) HashMaxItemSize((Page) metap)),
+				 errhint("Values larger than a buffer page cannot be indexed.")));
 
 	/*
 	 * Compute the target bucket number, and convert to block number.

src/backend/access/nbtree/nbtinsert.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.121 2005/06/06 20:22:57 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.122 2005/08/10 21:36:45 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -392,7 +392,10 @@ _bt_insertonpg(Relation rel,
 				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
 				 errmsg("index row size %lu exceeds btree maximum, %lu",
 						(unsigned long) itemsz,
-						(unsigned long) BTMaxItemSize(page))));
+						(unsigned long) BTMaxItemSize(page)),
+				 errhint("Values larger than 1/3 of a buffer page cannot be indexed\n"
+						 "Consider a separate column containing an MD5 hash of the value\n"
+						 "or use full text indexing.")));
 
 	/*
 	 * Determine exactly where new item will go.

src/backend/access/nbtree/nbtsort.c

@@ -56,7 +56,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/nbtree/nbtsort.c,v 1.91 2005/06/06 20:22:57 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/nbtree/nbtsort.c,v 1.92 2005/08/10 21:36:45 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -498,7 +498,10 @@ _bt_buildadd(BTWriteState *wstate, BTPageState *state, BTItem bti)
 				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
 				 errmsg("index row size %lu exceeds btree maximum, %lu",
 						(unsigned long) btisz,
-						(unsigned long) BTMaxItemSize(npage))));
+						(unsigned long) BTMaxItemSize(npage)),
+				 errhint("Values larger than 1/3 of a buffer page cannot be indexed\n"
+						 "Consider a separate column containing an MD5 hash of the value\n"
+						 "or use full text indexing.")));
 
 	if (pgspc < btisz || pgspc < state->btps_full)
 	{

src/backend/access/rtree/rtree.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/rtree/rtree.c,v 1.90 2005/06/06 17:01:22 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/rtree/rtree.c,v 1.91 2005/08/10 21:36:46 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -733,7 +733,8 @@ rtpicksplit(Relation r,
 				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
 				 errmsg("index row size %lu exceeds rtree maximum, %lu",
 						(unsigned long) newitemsz,
-						(unsigned long) RTPageAvailSpace)));
+						(unsigned long) RTPageAvailSpace),
+				 errhint("Values larger than a buffer page cannot be indexed.")));
 
 	maxoff = PageGetMaxOffsetNumber(page);
 	newitemoff = OffsetNumberNext(maxoff);		/* phony index for new