optimizations for geo index

arangod/GeoIndex/GeoIndex.cpp

@@ -654,10 +654,13 @@ void GeoMkDetail(GeoIx* gix, GeoDetailedPoint* gd, GeoCoordinate* c) {
   gd->gc = c;
   /* The GeoString computation takes about 0.17 microseconds  */
   gd->gs = GeoMkHilbert(c);
+  double const lat = c->latitude * M_PI / 180.0;
+  double const lon = c->longitude * M_PI / 180.0;
+  double const latCos = cos(lat);
   /* This part takes about 0.32 microseconds  */
-  gd->z = sin(c->latitude * M_PI / 180.0);
-  gd->x = cos(c->latitude * M_PI / 180.0) * cos(c->longitude * M_PI / 180.0);
-  gd->y = cos(c->latitude * M_PI / 180.0) * sin(c->longitude * M_PI / 180.0);
+  gd->z = sin(lat);
+  gd->x = latCos * cos(lon);
+  gd->y = latCos * sin(lon);
   /* And this bit takes about 0.45 microseconds  */
   for (int i = 0; i < GeoIndexFIXEDPOINTS; i++) {
     double xx1 = (gix->fixed.x)[i];
@@ -927,7 +930,7 @@ int GeoResultsGrow(GeoResults* gr) {
 /* distances that could be calculated by a separate    */
 /* call to GeoIndex_distance because of rounding errors*/
 /* =================================================== */
-GeoCoordinates* GeoAnswers(GeoIx* gix, GeoResults* gr) {
+GeoCoordinates* GeoAnswers(GeoIx* gix, GeoResults* gr, bool withDistances) {
   GeoCoordinates* ans;
   GeoCoordinate* gc;
   int i, j;
@@ -967,11 +970,14 @@ GeoCoordinates* GeoAnswers(GeoIx* gix, GeoResults* gr) {
     ans->coordinates[j].latitude = (gix->gc)[slot].latitude;
     ans->coordinates[j].longitude = (gix->gc)[slot].longitude;
     ans->coordinates[j].data = (gix->gc)[slot].data;
-    mole = sqrt(gr->snmd[i]);
-    if (mole > 2.0) mole = 2.0; /* make sure arcsin succeeds! */
-    gr->snmd[j] = 2.0 * EARTHRADIAN * asin(mole / 2.0);
+    if (withDistances) {
+      mole = sqrt(gr->snmd[i]);
+      if (mole > 2.0) mole = 2.0; /* make sure arcsin succeeds! */
+      gr->snmd[j] = 2.0 * EARTHRADIAN * asin(mole / 2.0);
+    }
     j++;
   }
+  // note that these are uncalculated if withDistances is false!
   ans->distances = gr->snmd;
 
   TRI_Free(TRI_UNKNOWN_MEM_ZONE, gr->slot);
@@ -1094,7 +1100,7 @@ GeoCoordinates* GeoIndex_PointsWithinRadius(GeoIdx* gi, GeoCoordinate* c,
       gk.potid[gk.stacksize++] = gp->RorPoints;
     }
   }
-  answer = GeoAnswers(gix, gres);
+  answer = GeoAnswers(gix, gres, true);
   return answer; /* note - this may be NULL  */
 }
 /* =================================================== */
@@ -1159,7 +1165,7 @@ GeoCoordinates* GeoIndex_NearestCountPoints(GeoIdx* gi, GeoCoordinate* c,
       }
     }
   }
-  answer = GeoAnswers(gix, gr);
+  answer = GeoAnswers(gix, gr, true);
   return answer; /* note - this may be NULL  */
 }
 /* =================================================== */
@@ -2060,7 +2066,7 @@ GeoCursor* GeoIndex_NewCursor(GeoIdx* gi, GeoCoordinate* c) {
   return (GeoCursor*)gcr;
 }
 
-GeoCoordinates* GeoIndex_ReadCursor(GeoCursor* gc, int count) {
+GeoCoordinates* GeoIndex_ReadCursor(GeoCursor* gc, int count, bool withDistances) {
   int i, j, r;
   GeoCoordinate* ct;
   GeoResults* gr;
@@ -2137,7 +2143,7 @@ GeoCoordinates* GeoIndex_ReadCursor(GeoCursor* gc, int count) {
       }
     }
   }
-  gcts = GeoAnswers(gcr->Ix, gr);
+  gcts = GeoAnswers(gcr->Ix, gr, withDistances);
   return gcts;
 }
 

arangod/GeoIndex/GeoIndex.h

@@ -101,7 +101,7 @@ GeoCoordinates* GeoIndex_PointsWithinRadius(GeoIdx* gi, GeoCoordinate* c,
 GeoCoordinates* GeoIndex_NearestCountPoints(GeoIdx* gi, GeoCoordinate* c,
                                             int count);
 GeoCursor* GeoIndex_NewCursor(GeoIdx* gi, GeoCoordinate* c);
-GeoCoordinates* GeoIndex_ReadCursor(GeoCursor* gc, int count);
+GeoCoordinates* GeoIndex_ReadCursor(GeoCursor* gc, int count, bool withDistances = true);
 void GeoIndex_CursorFree(GeoCursor* gc);
 void GeoIndex_CoordinatesFree(GeoCoordinates* clist);
 #ifdef TRI_GEO_DEBUG

arangod/Indexes/GeoIndex.cpp

@@ -127,31 +127,66 @@ void GeoIndexIterator::nextBabies(std::vector<IndexLookupResult>& result, size_t
   }
 
   if (batchSize > 0) {
-    auto coords = std::unique_ptr<GeoCoordinates>(::GeoIndex_ReadCursor(_cursor, batchSize));
+    // only need to calculate distances for WITHIN queries, but not for NEAR queries
+    bool const withDistances = !_near;
+    auto coords = std::unique_ptr<GeoCoordinates>(::GeoIndex_ReadCursor(_cursor, batchSize, withDistances));
 
     size_t const length = coords ? coords->length : 0;
-    if (!length) {
+    
+    if (length == 0) {
       return;
     }
 
     // determine which documents to return...
     size_t numDocs = length;
+
     if (!_near) {
       // WITHIN
       // only return those documents that are within the specified radius
       TRI_ASSERT(numDocs > 0);
-      // scan backwards because documents with higher distances are more interesting
-      // this can be improved to use a binary search if block size is increased in the future
-      while ((_inclusive && coords->distances[numDocs - 1] > _radius) ||
-            (!_inclusive && coords->distances[numDocs - 1] >= _radius)) {
-        // document is outside the specified radius!
-        --numDocs;
-        if (numDocs == 0) {
-          break;
+      
+      if (numDocs <= 8) {
+        // linear scan for the first document outside the specified radius
+        // scan backwards because documents with higher distances are more interesting
+        while ((_inclusive && coords->distances[numDocs - 1] > _radius) ||
+              (!_inclusive && coords->distances[numDocs - 1] >= _radius)) {
+          // document is outside the specified radius!
+          --numDocs;
+          if (numDocs == 0) {
+            break;
+          }
+        }
+      } else {
+        // binary search for documents inside/outside the specified radius
+        size_t l = 0;
+        size_t r = numDocs - 1;
+
+        while (true) {
+          // determine midpoint
+          size_t m = l + ((r - l) / 2);
+          if ((_inclusive && coords->distances[m] > _radius) ||
+              (!_inclusive && coords->distances[m] >= _radius)) {
+            // document is outside the specified radius!
+            if (m == 0) {
+              numDocs = 0;
+              break;
+            }
+            r = m - 1;
+          } else {
+            // still inside the radius
+            numDocs = m + 1;
+            l = m + 1;
+          }
+
+          if (r < l) {
+            break;
+          }
         }
       }
     }
-      
+  
+    result.reserve(numDocs);
+        
     for (size_t i = 0; i < numDocs; ++i) {
       result.emplace_back(IndexLookupResult(::GeoIndex::toRevision(coords->coordinates[i].data)));
     }