diff --git a/src/spatialjoin/SpatialJoinMain.cpp b/src/spatialjoin/SpatialJoinMain.cpp
index 9c8ba52..11f6d02 100755
--- a/src/spatialjoin/SpatialJoinMain.cpp
+++ b/src/spatialjoin/SpatialJoinMain.cpp
@@ -71,7 +71,9 @@ void printHelp(int argc, char** argv) {
       << std::setw(41) << "  --no-cutouts"
       << "disable cutouts\n"
       << std::setw(41) << "  --no-diag-box"
-      << "disable diagonal bounding-box based pre-filter" << std::endl;
+      << "disable diagonal bounding-box based pre-filter\n"
+      << std::setw(41) << "  --no-fast-sweep-skip"
+      << "disable fast sweep skip using binary search" << std::endl;
 }
 
 // _____________________________________________________________________________
@@ -103,6 +105,7 @@ int main(int argc, char** argv) {
   bool useOBB = true;
   bool useCutouts = true;
   bool useDiagBox = true;
+  bool useFastSweepSkip = true;
 
   for (int i = 1; i < argc; i++) {
     std::string cur = argv[i];
@@ -147,6 +150,8 @@ int main(int argc, char** argv) {
           useCutouts = false;
         } else if (cur == "--no-diag-box") {
           useDiagBox = false;
+        } else if (cur == "--no-fast-sweep-skip") {
+          useFastSweepSkip = false;
         } else {
           std::cerr << "Unknown option '" << cur << "', see -h" << std::endl;
           exit(1);
@@ -208,7 +213,7 @@ int main(int argc, char** argv) {
 
   Sweeper sweeper({NUM_THREADS, prefix, intersects, contains, covers, touches,
                    equals, overlaps, crosses, suffix, useBoxIds, useArea,
-                   useOBB, useCutouts, useDiagBox},
+                   useOBB, useCutouts, useDiagBox, useFastSweepSkip},
                   useCache, cache, output);
 
   if (!useCache) {
diff --git a/src/spatialjoin/Sweeper.cpp b/src/spatialjoin/Sweeper.cpp
index a5004e0..921ea12 100644
--- a/src/spatialjoin/Sweeper.cpp
+++ b/src/spatialjoin/Sweeper.cpp
@@ -24,6 +24,7 @@ using sj::boxids::BoxIdList;
 using sj::boxids::getBoxId;
 using sj::boxids::getBoxIds;
 using sj::boxids::packBoxIds;
+using util::writeAll;
 using util::geo::area;
 using util::geo::getBoundingBox;
 using util::geo::I32Line;
@@ -117,7 +118,7 @@ void Sweeper::multiAdd(const std::string& gid, int32_t xLeft, int32_t xRight) {
   } else {
     size_t id = _multiGidToId[gid];
     if (xRight > _multiRightX[id]) _multiRightX[id] = xRight;
-    if (xLeft > _multiLeftX[id]) _multiLeftX[id] = xLeft;
+    if (xLeft < _multiLeftX[id]) _multiLeftX[id] = xLeft;
   }
 }
 
@@ -131,7 +132,16 @@ void Sweeper::add(const I32Polygon& poly, const std::string& gid,
                   size_t subid) {
   const auto& box = getBoundingBox(poly);
   const auto& hull = util::geo::convexHull(poly);
-  const I32XSortedPolygon spoly(poly);
+  I32XSortedPolygon spoly(poly);
+
+  if (!_cfg.useFastSweepSkip) {
+    spoly.setInnerMaxSegLen(std::numeric_limits<int32_t>::max());
+    spoly.getOuter().setMaxSegLen(std::numeric_limits<int32_t>::max());
+    for (auto& inner : spoly.getInners()) {
+      inner.setMaxSegLen(std::numeric_limits<int32_t>::max());
+    }
+  }
+
   double areaSize = area(poly);
   double outerAreaSize = outerArea(poly);
   BoxIdList boxIds;
@@ -213,13 +223,15 @@ void Sweeper::add(const I32Line& line, const std::string& gid, size_t subid) {
     size_t id = _simpleLineCache.add({line.front(), line.back(), gid});
 
     diskAdd({id, box.getLowerLeft().getY(), box.getUpperRight().getY(),
-             box.getLowerLeft().getX(), false, SIMPLE_LINE, len,
-             box45});
+             box.getLowerLeft().getX(), false, SIMPLE_LINE, len, box45});
     diskAdd({id, box.getLowerLeft().getY(), box.getUpperRight().getY(),
-             box.getUpperRight().getX(), true, SIMPLE_LINE, len,
-             box45});
+             box.getUpperRight().getX(), true, SIMPLE_LINE, len, box45});
   } else {
-    const I32XSortedLine sline(line);
+    I32XSortedLine sline(line);
+
+    if (!_cfg.useFastSweepSkip) {
+      sline.setMaxSegLen(std::numeric_limits<int32_t>::max());
+    }
 
     size_t id =
         _lineCache.add({sline, box, gid, subid, len, boxIds, cutouts, obb});
@@ -429,21 +441,20 @@ void Sweeper::multiOut(size_t t, const std::string& gidA) {
 
 // _____________________________________________________________________________
 void Sweeper::flush() {
-  LOG(INFO) << _multiIds.size() << " multi geometries";
+  LOGTO(INFO, std::cerr) << _multiIds.size() << " multi geometries";
   for (size_t i = 0; i < _multiIds.size(); i++) {
     diskAdd({i, 1, 0, _multiLeftX[i] - 1, false, POINT, 0.0, {}});
   }
 
-  ssize_t r = write(_file, _outBuffer, _obufpos);
-  if (r < 0) throw std::runtime_error("Could not write to file.");
+  writeAll(_file, _outBuffer, _obufpos);
 
   _pointCache.flush();
   _areaCache.flush();
   _lineCache.flush();
   _simpleLineCache.flush();
+
   LOGTO(INFO, std::cerr) << "Sorting events...";
 
-  // now the individial parts are sorted
   std::string newFName = _cache + "/.sortTmp";
   int newFile = open(newFName.c_str(), O_RDWR | O_CREAT, 0666);
 
@@ -457,6 +468,8 @@ void Sweeper::flush() {
 #endif
   util::externalSort(_file, newFile, sizeof(BoxVal), _curSweepId, boxCmp);
 
+  fsync(newFile);
+
   // remove old file
   std::remove((_cache + "/events").c_str());
   std::rename((_cache + "/.sortTmp").c_str(), (_cache + "/events").c_str());
@@ -476,8 +489,7 @@ void Sweeper::diskAdd(const BoxVal& bv) {
   _obufpos += sizeof(BoxVal);
 
   if (_obufpos >= BUFFER_S) {
-    ssize_t r = write(_file, _outBuffer, BUFFER_S);
-    if (r < 0) throw std::runtime_error("Could not write to file.");
+    writeAll(_file, _outBuffer, BUFFER_S);
     _obufpos = 0;
   }
   _curSweepId++;
@@ -530,8 +542,7 @@ void Sweeper::sweep() {
         _activeMultis.insert(cur->id);
       } else if (!cur->out) {
         // IN event
-        actives.insert({cur->loY, cur->upY},
-                       {cur->id, cur->type, cur->b45});
+        actives.insert({cur->loY, cur->upY}, {cur->id, cur->type, cur->b45});
 
         if (jj % 500000 == 0) {
           auto lon = webMercToLatLng<double>((1.0 * cur->val) / PREC, 0).getX();
diff --git a/src/spatialjoin/Sweeper.h b/src/spatialjoin/Sweeper.h
index 622ce3c..0556723 100644
--- a/src/spatialjoin/Sweeper.h
+++ b/src/spatialjoin/Sweeper.h
@@ -84,10 +84,12 @@ struct SweeperCfg {
   bool useOBB;
   bool useCutouts;
   bool useDiagBox;
+  bool useFastSweepSkip;
 };
 
-// buffer sizes _must_ be multiples of sizeof(BoxVal)
-static const size_t BUFFER_S = sizeof(BoxVal) * 64 * 1024 * 1024;
+// buffer size _must_ be multiples of sizeof(BoxVal)
+static const ssize_t BUFFER_S = sizeof(BoxVal) * 64 * 1024 * 1024;
+
 static const size_t BUFFER_S_PAIRS = 1024 * 1024 * 10;
 
 class Sweeper {
@@ -167,7 +169,7 @@ class Sweeper {
   size_t _curSweepId = 0;
   int _file;
   unsigned char* _outBuffer;
-  size_t _obufpos;
+  ssize_t _obufpos;
 
   OutMode _outMode;
 
diff --git a/src/spatialjoin/tests/TestMain.cpp b/src/spatialjoin/tests/TestMain.cpp
index 69dbf84..4f4e981 100644
--- a/src/spatialjoin/tests/TestMain.cpp
+++ b/src/spatialjoin/tests/TestMain.cpp
@@ -17,7 +17,7 @@ using sj::Sweeper;
 std::string fullRun(const std::string& file) {
   Sweeper sweeper({1, "$", " intersects ", " contains ", " covers ",
                    " touches ", " equals ", " overlaps ", " crosses ", "$\n",
-                   true, true, true, true, true},
+                   true, true, true, true, true, true},
                   false, ".", ".resTmp");
 
   size_t gid = 0;
diff --git a/src/util b/src/util
index bbe6425..a814647 160000
--- a/src/util
+++ b/src/util
@@ -1 +1 @@
-Subproject commit bbe642559cf9b8d4a3625a2411243d80d4b39120
+Subproject commit a8146475fb1cbeb0308fb2fccd2d046f5c6618c7