diff -Nacr ./src/backend/access/heap/tuptoaster.c.orig ./src/backend/access/heap/tuptoaster.c
*** ./src/backend/access/heap/tuptoaster.c.orig	Mon Mar 21 13:23:58 2005
--- ./src/backend/access/heap/tuptoaster.c	Sun Jun 19 14:24:43 2005
***************
*** 1436,1438 ****
--- 1436,1482 ----
  
  	return result;
  }
+ 
+ /* ----------
+  * toast_datum_size
+  *
+  *	Show the (possibly compressed) size of a datum
+  * ----------
+  */
+ Size 
+ toast_datum_size(Datum value)
+ {
+ 
+ 	varattrib	*attr = (varattrib *) DatumGetPointer(value);
+ 	Size		result;
+ 
+ 	if (VARATT_IS_EXTERNAL(attr))
+ 	{
+ 		/*
+ 		 * Attribute is stored externally - If it is compressed too, 
+ 		 * then we need to get the external datum and calculate its size,
+ 		 * otherwise we just use the external rawsize.
+ 		 */
+ 		if (VARATT_IS_COMPRESSED(attr))
+ 		{
+ 			varattrib		*attrext = toast_fetch_datum(attr);
+ 			result = VARSIZE(attrext);
+ 			pfree(attrext);
+ 		}
+ 		else
+ 		{
+ 			result = attr->va_content.va_external.va_rawsize;
+ 		}
+ 	}
+ 	else
+ 	{
+ 		/*
+ 		 * Attribute is stored inline either compressed or not, just
+ 		 * calculate the size of the datum in either case.
+ 		 */
+ 		result = VARSIZE(attr);
+ 	}
+ 
+ 	return result;
+ 	
+ }
diff -Nacr ./src/backend/utils/adt/Makefile.orig ./src/backend/utils/adt/Makefile
*** ./src/backend/utils/adt/Makefile.orig	Fri Apr  2 09:28:45 2004
--- ./src/backend/utils/adt/Makefile	Fri Jun 17 17:52:09 2005
***************
*** 24,30 ****
  	tid.o timestamp.o varbit.o varchar.o varlena.o version.o xid.o \
  	network.o mac.o inet_net_ntop.o inet_net_pton.o \
  	ri_triggers.o pg_lzcompress.o pg_locale.o formatting.o \
! 	ascii.o quote.o pgstatfuncs.o encode.o
  
  like.o: like.c like_match.c
  
--- 24,30 ----
  	tid.o timestamp.o varbit.o varchar.o varlena.o version.o xid.o \
  	network.o mac.o inet_net_ntop.o inet_net_pton.o \
  	ri_triggers.o pg_lzcompress.o pg_locale.o formatting.o \
! 	ascii.o quote.o pgstatfuncs.o encode.o toastfuncs.o
  
  like.o: like.c like_match.c
  
diff -Nacr ./src/backend/utils/adt/toastfuncs.c.orig ./src/backend/utils/adt/toastfuncs.c
*** ./src/backend/utils/adt/toastfuncs.c.orig	Fri Jun 17 17:52:09 2005
--- ./src/backend/utils/adt/toastfuncs.c	Sun Jun 19 17:35:26 2005
***************
*** 0 ****
--- 1,74 ----
+ /*-------------------------------------------------------------------------
+  *
+  * toastfuncs.c
+  *	  Functions for accessing information about toasted data.
+  *
+  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
+  * Portions Copyright (c) 1994, Regents of the University of California
+  *
+  *
+  * IDENTIFICATION
+  *	  $PostgreSQL$
+  *
+  *-------------------------------------------------------------------------
+  */
+ 
+ #include "postgres.h"
+ #include "fmgr.h"
+ 
+ #include "catalog/pg_type.h"
+ #include "access/xact.h"
+ #include "access/tuptoaster.h"
+ #include "utils/builtins.h"
+ #include "utils/syscache.h"
+ 
+ Datum
+ pg_datum_length(PG_FUNCTION_ARGS)
+ {
+ 
+ 	Datum			value = PG_GETARG_DATUM(0);
+ 	int				size;
+ 
+ 
+ 	if (fcinfo->flinfo->fn_extra == NULL)
+ 	{
+ 		/*
+ 		 * On the first call check lookup the datatype of the supplied argument
+ 		 * and check if is a varlena .
+ 		 */
+ 		Oid				argtypeid = get_fn_expr_argtype(fcinfo->flinfo, 0);
+ 		HeapTuple		tp;
+ 		int				typlen;
+ 		
+ 		fcinfo->flinfo->fn_extra = MemoryContextAlloc(fcinfo->flinfo->fn_mcxt,
+ 													 sizeof(int));
+ 
+ 		tp = SearchSysCache(TYPEOID,
+ 							ObjectIdGetDatum(argtypeid),
+ 							0, 0, 0);
+ 		if (HeapTupleIsValid(tp)) 
+ 		{
+ 			Form_pg_type typtup = (Form_pg_type) GETSTRUCT(tp);
+ 			typlen = typtup->typlen;
+ 			ReleaseSysCache(tp);
+ 		}
+ 		else
+ 		{
+ 			/* Oid not in pg_type, should never happen. */
+ 			elog(ERROR, "invalid typid %u", argtypeid);
+ 		}
+ 
+ 
+ 
+ 		if ( typlen != -1 )
+ 		{
+ 			elog(ERROR, "this function is only applicable to varlena types");
+ 		}
+ 	}
+ 	
+ 
+ 	size = toast_datum_size(value) - VARHDRSZ;
+ 
+ 	PG_RETURN_INT32(size);
+ }
+ 
diff -Nacr ./src/include/access/tuptoaster.h.orig ./src/include/access/tuptoaster.h
*** ./src/include/access/tuptoaster.h.orig	Mon Mar 21 13:24:04 2005
--- ./src/include/access/tuptoaster.h	Sun Jun 19 14:45:18 2005
***************
*** 138,141 ****
--- 138,149 ----
   */
  extern Size toast_raw_datum_size(Datum value);
  
+ /* ----------
+  * toast_datum_size -
+  *
+  *	Return the (possibly compressed) size of a varlena datum
+  * ----------
+  */
+ extern Size toast_datum_size(Datum value);
+ 
  #endif   /* TUPTOASTER_H */
diff -Nacr ./src/include/catalog/pg_proc.h.orig ./src/include/catalog/pg_proc.h
*** ./src/include/catalog/pg_proc.h.orig	Wed Jun 15 09:04:41 2005
--- ./src/include/catalog/pg_proc.h	Sun Jun 19 17:08:35 2005
***************
*** 3655,3660 ****
--- 3655,3664 ----
  DATA(insert OID = 2560 (  pg_postmaster_start_time PGNSP PGUID 12 f f t f s 0 1184 "" _null_ _null_ _null_ pgsql_postmaster_start_time - _null_ ));
  DESCR("postmaster start time");
  
+ /* Toast compressed length */
+ DATA(insert OID = 2561 (  pg_datum_length	   PGNSP PGUID 12 f f t f i 1 23 "2276" _null_ _null_ _null_  pg_datum_length - _null_ ));
+ DESCR("length (possibly compressed) of varlena types");
+ 
  
  /*
   * Symbolic values for provolatile column: these indicate whether the result
diff -Nacr ./src/include/utils/builtins.h.orig ./src/include/utils/builtins.h
*** ./src/include/utils/builtins.h.orig	Fri May 27 12:57:49 2005
--- ./src/include/utils/builtins.h	Sun Jun 19 12:48:35 2005
***************
*** 828,831 ****
--- 828,834 ----
  /* catalog/pg_conversion.c */
  extern Datum pg_convert_using(PG_FUNCTION_ARGS);
  
+ /* toastfuncs.c */
+ extern Datum pg_datum_length(PG_FUNCTION_ARGS);
+ 
  #endif   /* BUILTINS_H */