diff --git a/docs/yap.tex b/docs/yap.tex
index 021a709f7..02948f03b 100644
--- a/docs/yap.tex
+++ b/docs/yap.tex
@@ -200,6 +200,7 @@ Subnodes of Library
 * Heaps:: Labelled binary tree where the key of each node is less
     than or equal to the keys of its children.
 * Lambda:: Ulrich Neumerkel's Lambda Library
+* DBUsage:: Information bout data base usage.
 * LineUtilities:: Line Manipulation Utilities
 * Lists:: List Manipulation
 * MapList:: SWI-Compatible Apply library.
@@ -8660,6 +8661,7 @@ Library, Extensions, Built-ins, Top
     than or equal to the keys of its children.
 * LAM:: LAM MPI
 * Lambda:: Ulrich Neumerkel's Lambda Library
+* DBUsage:: Information bout data base usage.
 * Lists:: List Manipulation
 * LineUtilities:: Line Manipulation Utilities
 * MapList:: SWI-Compatible Apply library.
@@ -12697,7 +12699,7 @@ The vertices @var{Vertices} have no outgoing edge in graph
 
 @end table
 
-@node UnDGraphs, Lambda , DGraphs, Library
+@node UnDGraphs, DBUsage , DGraphs, Library
 @section Undirected Graphs
 @cindex undirected graphs
 
@@ -12793,7 +12795,50 @@ directed graph @var{DGraph}.
 
 @end table
 
-@node Lambda, LAM, UnDGraphs, Library
+@node DBUsage, Lambda, UnDGraphs, Library
+@section Memory Usage in Prolog Data-Base
+@cindex DBUsage
+
+This library provides a set of utilities for studying memory usage in YAP.
+The following routines are available once included with the
+@code{use_module(library(dbusage))} command.
+
+@table @code
+@item db_usage
+@findex db_usage/0
+@snindex db_usage/0
+@cnindex db_usage/0
+Give general overview of data-base usage in the system.
+
+@item db_static
+@findex db_static/0
+@snindex db_static/0
+@cnindex db_static/0
+List memory usage for every static predicate.
+
+@item db_static(+@var{Threshold})
+@findex db_static/0
+@snindex db_static/0
+@cnindex db_static/0
+List memory usage for every static predicate. Predicate must use more
+than @var{Threshold} bytes.
+
+@item db_dynamic
+@findex db_dynamic/0
+@snindex db_dynamic/0
+@cnindex db_dynamic/0
+List memory usage for every dynamic predicate.
+
+@item db_dynamic(+@var{Threshold})
+@findex db_dynamic/0
+@snindex db_dynamic/0
+@cnindex db_dynamic/0
+List memory usage for every dynamic predicate. Predicate must use more
+than @var{Threshold} bytes.
+
+@end table
+
+@node Lambda, LAM, DBUsage, Library
 @section Lambda Expressions
 @cindex Lambda Expressions
 
diff --git a/library/dbusage.yap b/library/dbusage.yap
index e525440fa..f67235ee8 100644
--- a/library/dbusage.yap
+++ b/library/dbusage.yap
@@ -2,7 +2,9 @@
 :- module(dbusage, [
 	db_usage/0,
 	db_static/0,
-	db_dynamic/0
+	db_static/1,
+	db_dynamic/0,
+	db_dynamic/1
     ]).
 
 db_usage :-
@@ -13,8 +15,8 @@ db_usage :-
 	HeapUsedK is HeapUsed//1024,
 	HeapFreeK is HeapFree//1024,
 	StackSpace is (GInU+SInU+FreeS+TInU+FreeT)//1024,
-	format(user_error, 'Heap Space = ~d KB (+ ~dKB free)~n',[HeapUsedK,HeapFreeK]),	
-	format(user_error, 'Stack Space = ~d KB~n',[StackSpace]),	
+	format(user_error, 'Heap Space = ~D KB (+ ~D KB free)~n',[HeapUsedK,HeapFreeK]),	
+	format(user_error, 'Stack Space = ~D KB~n',[StackSpace]),	
 	findall(p(Cls,CSz,ISz),
 		(current_module(M),
 		 current_predicate(_,M:P),
@@ -22,12 +24,12 @@ db_usage :-
 	sumall(LAll, TCls, TCSz, TISz),
 	statistics(atoms,[AtomN,AtomS]),
 	AtomSK is AtomS//1024,
-	format(user_error, '~d Atoms taking ~d KB~n',[AtomN,AtomSK]),
+	format(user_error, '~D Atoms taking ~D KB~n',[AtomN,AtomSK]),
 	TSz is TCSz+TISz,
 	TSzK is TSz//1024,
 	TCSzK is TCSz//1024,
 	TISzK is TISz//1024,
-	format(user_error, 'Total User Code~n    ~d clauses taking ~d KB~n    ~d KB in clauses + ~d KB in indices~n',
+	format(user_error, 'Total User Code~n    ~D clauses taking ~D KB~n    ~D KB in clauses + ~D KB in indices~n',
 	       [TCls,TSzK,TCSzK,TISzK]),
 	statistics(static_code,[SCl,SI,SI1,SI2,SI3]),
 	SClK is SCl//1024,
@@ -37,7 +39,7 @@ db_usage :-
 	SI3K is SI3//1024,
 	ST is SCl+SI,
 	STK is ST//1024,
-	format(user_error, 'Total Static code=~d KB~n    ~dKB in clauses + ~dKB in indices (~d+~d+~d)~n',
+	format(user_error, 'Total Static code=~D KB~n    ~D KB in clauses + ~D KB in indices (~D+~D+~D)~n',
 	       [STK,SClK,SIK,SI1K,SI2K,SI3K]),
 	statistics(dynamic_code,[DCl,DI,DI1,DI2,DI3,DI4]),
 	DClK is DCl//1024,
@@ -48,20 +50,20 @@ db_usage :-
 	DI4K is DI4//1024,
 	DT is DCl+DI,
 	DTK is DT//1024,
-	format(user_error, 'Total Dynamic code=~d KB~n    ~dKB in clauses + ~dKB in indices (~d+~d+~d+~d)~n',
+	format(user_error, 'Total Dynamic code=~D KB~n    ~D KB in clauses + ~D KB in indices (~D+~D+~D+~D)~n',
 	       [DTK,DClK,DIK,DI1K,DI2K,DI3K,DI4K]),
 	total_erased(DCls,DSZ,ICls,ISZ),
 	(DCls =:= 0 ->
 	 true
 	;
 	 DSZK is DSZ//1024,
-	 format(user_error, '    ~d erased clauses not reclaimed (~dKB)~n',[DCls,DSZK])
+	 format(user_error, '    ~D erased clauses not reclaimed (~D KB)~n',[DCls,DSZK])
 	),
 	(ICls =:= 0 ->
 	 true
 	;
 	 ISZK is ISZ//1024,
-	 format(user_error, '    ~d erased indices not reclaimed (~dKB)~n',[ICls,ISZK])
+	 format(user_error, '    ~D erased indices not reclaimed (~D KB)~n',[ICls,ISZK])
 	),
 	!.
 
@@ -70,23 +72,31 @@ db_usage:-
 
 
 db_static :-
+    db_static(-1).
+
+db_static(Min) :-
 	setof(p(Sz,M:P,Cls,CSz,ISz),
 	      PN^(current_module(M),
 	       current_predicate(PN,M:P),
 	       \+ predicate_property(M:P,dynamic),
 	       predicate_statistics(M:P,Cls,CSz,ISz),
-	       Sz is (CSz+ISz)),All),
+		  Sz is (CSz+ISz),
+		  Sz > Min),All),
 	format(user_error,' Static user code~n===========================~n',[]),
 	display_preds(All).
 
 db_dynamic :-
+    db_dynamic(-1).
+
+db_dynamic(Min) :-
 	setof(p(Sz,M:P,Cls,CSz,ISz,ECls,ECSz,EISz),
 	      PN^(current_module(M),
 		  current_predicate(PN,M:P),
 		  predicate_property(M:P,dynamic),
 		  predicate_statistics(M:P,Cls,CSz,ISz),
 		  predicate_erased_statistics(M:P,ECls,ECSz,EISz),
-		  Sz is (CSz+ISz+ECSz+EISz)),
+		  Sz is (CSz+ISz+ECSz+EISz),
+		  Sz < Min),
 	      All),
 	format(user_error,' Dynamic user code~n===========================~n',[]),
 	display_dpreds(All).
@@ -98,7 +108,7 @@ display_preds([p(Sz,M:P,Cls,CSz,ISz)|_]) :-
 	KCSz is CSz//1024,
 	KISz is ISz//1024,
 	(M = user -> Name = A/N ; Name = M:A/N),
-	format(user_error,'~w~t~36+:~t~d~7+ clauses using~|~t~d~8+ KB (~d + ~d)~n',[Name,Cls,KSz,KCSz,KISz]),
+	format(user_error,'~w~t~36+:~t~D~7+ clauses using~|~t~D~8+ KB (~D + ~D)~n',[Name,Cls,KSz,KCSz,KISz]),
 	fail.
 display_preds([_|All]) :-
 	display_preds(All).
@@ -111,20 +121,20 @@ display_dpreds([p(Sz,M:P,Cls,CSz,ISz,ECls,ECSz,EISz)|_]) :-
 	KCSz is CSz//1024,
 	KISz is ISz//1024,
 	(M = user -> Name = A/N ; Name = M:A/N),
-	format(user_error,'~w~t~36+:~t~d~7+ clauses using~|~t~d~8+ KB (~d + ~d)~n',[Name,Cls,KSz,KCSz,KISz]),
+	format(user_error,'~w~t~36+:~t~D~7+ clauses using~|~t~D~8+ KB (~D + ~D)~n',[Name,Cls,KSz,KCSz,KISz]),
 	(ECls =:= 0
 	->
 	 true
 	;
 	 ECSzK is ECSz//1024,
-	 format(user_error,'                        ~d erased clauses: ~d KB~n',[ECls,ECSzK])
+	 format(user_error,'                        ~D erased clauses: ~D KB~n',[ECls,ECSzK])
 	),
 	(EISz =:= 0
 	->
 	 true
 	;
 	 EISzK is EISz//1024,
-	 format(user_error,'                        ~d KB erased indices~n',[EISzK])
+	 format(user_error,'                        ~D KB erased indices~n',[EISzK])
 	),
 	fail.
 display_dpreds([_|All]) :-