diff --git a/C/adtdefs.c b/C/adtdefs.c
index 2674a924c..45ca800bf 100644
--- a/C/adtdefs.c
+++ b/C/adtdefs.c
@@ -311,6 +311,12 @@ GetPredPropByAtomHavingLock(AtomEntry* ae, SMALLUNSGN cur_mod)
     if ( pe->KindOfPE == PEProp && 
 	 (pe->ModuleOfPred == cur_mod || !pe->ModuleOfPred)) {
       return(p0);
+#if THREADS
+      /* Thread Local Predicates */
+      if (pe->PredFlags & ThreadLocalPredFlag) {
+	return AbsPredProp(Yap_GetThreadPred(pe));
+      }
+#endif
     }
     p0 = pe->NextOfPE;
   }
@@ -341,6 +347,12 @@ GetPredPropByAtomHavingLockInThisModule(AtomEntry* ae, SMALLUNSGN cur_mod)
   while (p0) {
     PredEntry *pe = RepPredProp(p0);
     if ( pe->KindOfPE == PEProp && pe->ModuleOfPred == cur_mod ) {
+#if THREADS
+      /* Thread Local Predicates */
+      if (pe->PredFlags & ThreadLocalPredFlag) {
+	return AbsPredProp(Yap_GetThreadPred(pe));
+      }
+#endif
       return(p0);
     }
     p0 = pe->NextOfPE;
@@ -374,6 +386,12 @@ GetPredPropByFuncHavingLock(Functor f, SMALLUNSGN cur_mod)
     PredEntry *p = RepPredProp(p0);
     if (/* p->KindOfPE != 0 || only props */
 	(p->ModuleOfPred == cur_mod || !(p->ModuleOfPred))) {
+#if THREADS
+      /* Thread Local Predicates */
+      if (p->PredFlags & ThreadLocalPredFlag) {
+	return AbsPredProp(Yap_GetThreadPred(p));
+      }
+#endif
       return (p0);
     }
     p0 = p->NextOfPE;
@@ -404,6 +422,12 @@ GetPredPropByFuncHavingLockInThisModule(Functor f, SMALLUNSGN cur_mod)
   while (p0) {
     PredEntry *p = RepPredProp(p0);
     if (p->ModuleOfPred == cur_mod) {
+#if THREADS
+      /* Thread Local Predicates */
+      if (p->PredFlags & ThreadLocalPredFlag) {
+	return AbsPredProp(Yap_GetThreadPred(p));
+      }
+#endif
       return (p0);
     }
     p0 = p->NextOfPE;
diff --git a/C/dbase.c b/C/dbase.c
index b309f49c9..2fce7ed0c 100644
--- a/C/dbase.c
+++ b/C/dbase.c
@@ -4902,6 +4902,48 @@ Yap_ReleaseTermFromDB(DBTerm *ref)
   ReleaseTermFromDB(ref);
 }
 
+static Int 
+p_install_thread_local(void)
+{				/* '$is_dynamic'(+P)	 */
+  PredEntry      *pe;
+  Term            t = Deref(ARG1);
+  Term            t2 = Deref(ARG2);
+  SMALLUNSGN      mod = Yap_LookupModule(t2);
+
+  if (IsVarTerm(t)) {
+    return (FALSE);
+  }
+  if (mod == IDB_MODULE) {
+    pe = find_lu_entry(t); 
+    if (!pe->cs.p_code.NOfClauses) {
+      if (IsIntegerTerm(t)) 
+	pe->PredFlags |= LogUpdatePredFlag|NumberDBPredFlag;
+      else if (IsAtomTerm(t))
+	pe->PredFlags |= LogUpdatePredFlag|AtomDBPredFlag;
+      else
+	pe->PredFlags |= LogUpdatePredFlag;
+    }
+  } else if (IsAtomTerm(t)) {
+    Atom at = AtomOfTerm(t);
+    pe = RepPredProp(PredPropByAtom(at, mod));
+  } else if (IsApplTerm(t)) {
+    Functor         fun = FunctorOfTerm(t);
+    pe = RepPredProp(PredPropByFunc(fun, mod));
+  } else {
+    return FALSE;
+  }
+  WRITE_LOCK(pe->PRWLock);
+  if (pe->PredFlags & (UserCPredFlag|HiddenPredFlag|CArgsPredFlag|SyncPredFlag|TestPredFlag|AsmPredFlag|StandardPredFlag|CPredFlag|SafePredFlag|IndexedPredFlag|BinaryTestPredFlag) ||
+      pe->cs.p_code.NOfClauses) {
+    return FALSE;
+  }
+  pe->PredFlags |= ThreadLocalPredFlag;
+  pe->OpcodeOfPred = Yap_opcode(_thread_local);
+  pe->CodeOfPred = (yamop *)&pe->OpcodeOfPred;
+  WRITE_UNLOCK(pe->PRWLock);
+  return TRUE;
+}
+
 void 
 Yap_InitDBPreds(void)
 {
@@ -4943,6 +4985,7 @@ Yap_InitDBPreds(void)
   Yap_InitCPred("nth_instance", 3, p_nth_instance, SyncPredFlag);
   Yap_InitCPred("$nth_instancep", 3, p_nth_instancep, SyncPredFlag);
   Yap_InitCPred("$jump_to_next_dynamic_clause", 0, p_jump_to_next_dynamic_clause, SyncPredFlag);
+  Yap_InitCPred("$install_thread_local", 2, p_install_thread_local, SafePredFlag);
 }
 
 void 
diff --git a/C/threads.c b/C/threads.c
index 56ae1f13e..eff774832 100644
--- a/C/threads.c
+++ b/C/threads.c
@@ -354,35 +354,6 @@ p_cond_wait(void)
   return TRUE;
 }
 
-static Int 
-p_install_thread_local(void)
-{				/* '$is_dynamic'(+P)	 */
-  PredEntry      *pe;
-  Term            t = Deref(ARG1);
-  Term            t2 = Deref(ARG2);
-  SMALLUNSGN      mod = Yap_LookupModule(t2);
-
-  if (IsVarTerm(t)) {
-    return (FALSE);
-  } else if (IsAtomTerm(t)) {
-    Atom at = AtomOfTerm(t);
-    pe = RepPredProp(PredPropByAtom(at, mod));
-  } else if (IsApplTerm(t)) {
-    Functor         fun = FunctorOfTerm(t);
-    pe = RepPredProp(PredPropByFunc(fun, mod));
-  } else
-    return FALSE;
-  WRITE_LOCK(pe->PRWLock);
-  if (pe->PredFlags & (UserCPredFlag|HiddenPredFlag|CArgsPredFlag|SyncPredFlag|TestPredFlag|AsmPredFlag|StandardPredFlag|CPredFlag|SafePredFlag|IndexedPredFlag|BinaryTestPredFlag) ||
-      pe->cs.p_code.FirstClause != NULL) {
-    return FALSE;
-  }
-  pe->PredFlags |= ThreadLocalPredFlag;
-  pe->OpcodeOfPred = Yap_opcode(_thread_local);
-  pe->CodeOfPred = (yamop *)&pe->OpcodeOfPred;
-  WRITE_UNLOCK(pe->PRWLock);
-  return TRUE;
-}
 
 static Int 
 p_thread_signal(void)
@@ -426,7 +397,6 @@ void Yap_InitThreadPreds(void)
   Yap_InitCPred("$cond_signal", 1, p_cond_signal, SafePredFlag);
   Yap_InitCPred("$cond_broadcast", 1, p_cond_broadcast, SafePredFlag);
   Yap_InitCPred("$cond_wait", 2, p_cond_wait, SafePredFlag);
-  Yap_InitCPred("$install_thread_local", 2, p_install_thread_local, SafePredFlag);
   Yap_InitCPred("$signal_thread", 1, p_thread_signal, SafePredFlag);
 }
 
diff --git a/config.h.in b/config.h.in
index fd9db27d3..3910483de 100644
--- a/config.h.in
+++ b/config.h.in
@@ -43,6 +43,7 @@
 
 #undef SUPPORT_CONDOR
 #undef SUPPORT_THREADS
+#undef USE_PTHREAD_LOCKING
 
 #undef HAVE_SYS_WAIT_H
 #undef NO_UNION_WAIT