Ticket #250: lazy_positionmods.patch

common/document.h

@@ -59 +59 @@
         bool data_here;
         mutable bool values_here; // FIXME mutable is a hack
         mutable bool terms_here;
+        bool positions_touched;
 
         /// The (user defined) data associated with this document.
         string data;
@@ -174 +175 @@
             return terms_here;
         }
 
+        /** Return true if the positions in the document may have been modified.
+         */
+        bool positions_modified() const {
+            return positions_touched;
+        }
+
         /** Get the docid which is associated with this document (if any).
          *
          *  NB If multiple databases are being searched together, then this
@@ -196 +203 @@
         Internal(Xapian::Internal::RefCntPtr<const Xapian::Database::Internal> database_,
                  Xapian::docid did_)
             : database(database_), data_here(false), values_here(false),
-              terms_here(false), did(did_) { }
+              terms_here(false), positions_touched(false), did(did_) { }
 
         Internal()
             : database(0), data_here(false), values_here(false),
-              terms_here(false) { }
+              terms_here(false), positions_touched(false) { }
 
         /** Destructor.
          *

api/omdocument.cc

@@ -359 +359 @@
         i->second.add_position(tpos);
         if (wdfinc) i->second.inc_wdf(wdfinc);
     }
+    positions_touched = true;
 }
 
 void
@@ -391 +392 @@
                 "Xapian::Document::Internal::remove_posting()");
     }
     i->second.remove_position(tpos);
+    positions_touched = true;
     if (wdfdec) i->second.dec_wdf(wdfdec);
 }
 
@@ -405 +407 @@
                 "' is not present in document, in "
                 "Xapian::Document::Internal::remove_term()");
     }
+    if (!(i->second.positions.empty())) {
+        positions_touched = true;
+    }
     terms.erase(i);
 }
         
@@ -413 +418 @@
 {
     terms.clear();
     terms_here = true;
+    positions_touched = true;
 }
 
 Xapian::termcount

backends/flint/flint_database.cc

@@ -1361 +1361 @@
                     j->second.insert(make_pair(did, make_pair('A', wdf)));
                 }
 
-                PositionIterator it = term.positionlist_begin();
-                PositionIterator it_end = term.positionlist_end();
-                if (it != it_end) {
-                    position_table.set_positionlist(
-                        did, tname, it, it_end);
-                } else {
-                    position_table.delete_positionlist(did, tname);
+                if (!modifying || document.internal->positions_modified()) {
+                    PositionIterator it = term.positionlist_begin();
+                    PositionIterator it_end = term.positionlist_end();
+                    if (it != it_end) {
+                        position_table.set_positionlist(did, tname, it, it_end);
+                    } else {
+                        position_table.delete_positionlist(did, tname);
+                    }
                 }
             }
             LOGLINE(DB, "Calculated doclen for replacement document " << did << " as " << new_doclen);