Index: generic/schema.c
==================================================================
--- generic/schema.c
+++ generic/schema.c
@@ -496,10 +496,11 @@
     sdata->cdata = TMALLOC (Tcl_DString);
     Tcl_DStringInit (sdata->cdata);
     Tcl_InitHashTable (&sdata->ids, TCL_STRING_KEYS);
     sdata->unknownIDrefs = 0;
     Tcl_InitHashTable (&sdata->idTables, TCL_STRING_KEYS);
+    Tcl_InitHashTable (&sdata->keySpaces, TCL_STRING_KEYS);
     return sdata;
 }
 
 static void schemaInstanceDelete (
     ClientData clientData
@@ -509,10 +510,11 @@
     unsigned int i;
     SchemaValidationStack *down;
     Tcl_HashEntry *h;
     Tcl_HashSearch search;
     SchemaDocKey *dk;
+    SchemaKeySpace *ks;
 
     /* Protect the clientData to be freed inside (even nested)
      * Tcl_Eval*() calls to avoid invalid mem access and postpone the
      * cleanup until the Tcl_Eval*() calls are finished (done in
      * schemaInstanceCmd(). */
@@ -574,10 +576,19 @@
         dk = Tcl_GetHashValue (h);
         Tcl_DeleteHashTable (&dk->ids);
         FREE (dk);
     }
     Tcl_DeleteHashTable (&sdata->idTables);
+    for (h = Tcl_FirstHashEntry (&sdata->keySpaces, &search);
+         h != NULL;
+         h = Tcl_NextHashEntry (&search)) {
+        ks = Tcl_GetHashValue (h);
+        if (ks->active) {
+            Tcl_DeleteHashTable (&dk->ids);
+        }
+        FREE (ks);
+    }
     FREE (sdata);
 }
 
 static void
 cleanupLastPattern (
@@ -964,17 +975,31 @@
                 if (rc == 1) {
                     updateStack (se, cp, ac);
                     return 1;
                 }
                 popStack (sdata);
-
                 break;
+
             case SCHEMA_CTYPE_KEYSPACE_END:
-
+                candidate->keySpace->active--;
+                if (!candidate->keySpace->active) {
+                    if (candidate->keySpace->unknownIDrefs) {
+                        /* Recover or report error */
+                    }
+                    Tcl_DeleteHashTable (&candidate->keySpace->ids);
+                }
                 break;
+
             case SCHEMA_CTYPE_KEYSPACE:
-
+                if (!candidate->keySpace->active) {
+                    Tcl_InitHashTable (&candidate->keySpace->ids,
+                                       TCL_STRING_KEYS);
+                    candidate->keySpace->active = 1;
+                    candidate->keySpace->unknownIDrefs = 0;
+                } else {
+                    candidate->keySpace->active++;
+                }
                 break;
             }
             if (!mayskip && mustMatch (cp->quants[ac], hm)) {
                 if (recover (interp, sdata, S("MISSING_CP"))) {
                     /* Skip the just opened element tag and the following
@@ -1828,11 +1853,11 @@
 
                 case SCHEMA_CTYPE_KEYSPACE:
 
                     break;
                     
-                case SCHEMA_CTYPE_KEYSPACE:
+                case SCHEMA_CTYPE_KEYSPACE_END:
 
                     break;
                     
                 case SCHEMA_CTYPE_NAME:
                 case SCHEMA_CTYPE_ANY:
@@ -1901,11 +1926,11 @@
             
         case SCHEMA_CTYPE_KEYSPACE:
 
             break;
             
-        case SCHEMA_CTYPE_KEYSPACE:
+        case SCHEMA_CTYPE_KEYSPACE_END:
 
             break;
         }
         break;
     }
@@ -3818,13 +3843,15 @@
     Tcl_Obj *const objv[]
     )
 {
     SchemaData *sdata = GETASI;
     SchemaCP *pattern;
-    int nrKeyspaces, i;
+    int nrKeyspaces, i, hnew;
     Tcl_Obj *ksObj;
-
+    SchemaKeySpace *ks;
+    Tcl_HashEntry *h;
+    
     CHECK_SI
     CHECK_TOPLEVEL
     checkNrArgs (3, 3, "Expected: <keyspace-name list> pattern");
     if (sdata->cp->type != SCHEMA_CTYPE_NAME
         && sdata->cp->type != SCHEMA_CTYPE_PATTERN) {
@@ -3848,13 +3875,24 @@
     if (Tcl_EvalObjEx (interp, objv[2], TCL_EVAL_DIRECT) != TCL_OK) {
         return TCL_ERROR;
     }
     for (i = 0; i < nrKeyspaces; i++) {
         Tcl_ListObjIndex (interp, objv[1], i, &ksObj);
+        h = Tcl_CreateHashEntry (&sdata->keySpaces,
+                                 Tcl_GetString (ksObj), &hnew);
+        if (hnew) {
+            ks = TMALLOC (SchemaKeySpace);
+            ks->active = 0;
+            ks->unknownIDrefs = 0;
+            Tcl_SetHashValue (h, ks);
+        } else {
+            ks = Tcl_GetHashValue (h);
+        }
         pattern = initSchemaCP (SCHEMA_CTYPE_KEYSPACE_END,
                                 Tcl_GetString (ksObj), NULL);
         REMEMBER_PATTERN (pattern);
+        pattern->keySpace = ks;
         addToContent (sdata, pattern, SCHEMA_CQUANT_ONE, 0, 0);
     }
     return TCL_OK;
 }
 

Index: generic/schema.h
==================================================================
--- generic/schema.h
+++ generic/schema.h
@@ -33,11 +33,12 @@
   SCHEMA_CTYPE_CHOICE,
   SCHEMA_CTYPE_INTERLEAVE,
   SCHEMA_CTYPE_PATTERN,
   SCHEMA_CTYPE_TEXT,
   SCHEMA_CTYPE_VIRTUAL,
-  SCHEMA_CTYPE_KEYSPACE
+  SCHEMA_CTYPE_KEYSPACE,
+  SCHEMA_CTYPE_KEYSPACE_END
 } Schema_CP_Type;
 
 typedef enum {
   SCHEMA_CQUANT_ONE,
   SCHEMA_CQUANT_OPT,
@@ -83,10 +84,17 @@
     int    nrFields;
     int    flags;
     struct domKeyConstraint *next;
 } domKeyConstraint;
 
+typedef struct 
+{
+    int active;
+    Tcl_HashTable ids;
+    int unknownIDrefs;
+} SchemaKeySpace;
+
 typedef struct SchemaCP
 {
     Schema_CP_Type    type;
     char             *namespace;
     char             *name;
@@ -97,10 +105,11 @@
     unsigned int      nc;
     SchemaAttr      **attrs;
     unsigned int      numAttr;
     unsigned int      numReqAttr;
     domKeyConstraint *domKeys;
+    SchemaKeySpace   *keySpace;
 } SchemaCP;
 
 typedef struct SchemaValidationStack
 {
     SchemaCP *pattern;
@@ -121,11 +130,11 @@
 typedef struct 
 {
     Tcl_HashTable ids;
     int unknownIDrefs;
 } SchemaDocKey;
-    
+
 typedef struct SchemaData_
 {
     Tcl_Obj *self;
     char *start;
     char *startNamespace;
@@ -166,10 +175,11 @@
     unsigned int skipDeep;
     Tcl_DString *cdata;
     Tcl_HashTable ids;
     int unknownIDrefs;
     Tcl_HashTable idTables;
+    Tcl_HashTable keySpaces;
 } SchemaData;
 
 int 
 schemaInstanceCmd (
     ClientData clientData,