diff --git a/package.json b/package.json
index 88600a9..6ba0eb6 100644
--- a/package.json
+++ b/package.json
@@ -7,7 +7,7 @@
     "url": "git://github.com/mapbox/carmen-cache.git",
     "type": "git"
   },
-  "version": "0.21.3",
+  "version": "0.21.3-optimize",
   "dependencies": {
     "nan": "~2.10.0",
     "node-pre-gyp": "~0.10.1"
diff --git a/src/coalesce.cpp b/src/coalesce.cpp
index 83c8cee..dfed496 100644
--- a/src/coalesce.cpp
+++ b/src/coalesce.cpp
@@ -388,7 +388,6 @@ void coalesceSingle(uv_work_t* req) {
         unsigned long m = grids.size();
         double relevMax = 0;
         std::vector<Cover> covers;
-        covers.reserve(m);
 
         uint32_t length = 0;
         uint32_t lastId = 0;
@@ -438,7 +437,6 @@ void coalesceSingle(uv_work_t* req) {
         std::size_t added = 0;
         std::vector<Context> contexts;
         std::size_t max_contexts = 40;
-        contexts.reserve(max_contexts);
         for (auto&& cover : covers) {
             // Stop at 40 contexts
             if (added == max_contexts) break;
@@ -453,7 +451,6 @@ void coalesceSingle(uv_work_t* req) {
             uint32_t mask = 0;
             contexts.emplace_back(std::move(cover), mask, relev);
         }
-
         coalesceFinalize(baton, std::move(contexts));
     } catch (std::exception const& ex) {
         baton->error = ex.what();
@@ -473,8 +470,10 @@ void coalesceMulti(uv_work_t* req) {
         // Cache zoom levels to iterate over as coalesce occurs.
         std::vector<intarray> zoomCache;
         zoomCache.reserve(stackSize);
+        double maxrelev = 0;
         for (auto const& subq : stack) {
-            intarray zooms;
+            zoomCache.emplace_back();
+            auto& zooms = zoomCache.back();
             std::vector<bool> zoomUniq(22, false);
             for (auto const& subqB : stack) {
                 if (subq.idx == subqB.idx) continue;
@@ -483,7 +482,6 @@ void coalesceMulti(uv_work_t* req) {
                 zoomUniq[subqB.zoom] = true;
                 zooms.emplace_back(subqB.zoom);
             }
-            zoomCache.push_back(std::move(zooms));
         }
 
         // Coalesce relevs into higher zooms, e.g.
@@ -570,12 +568,8 @@ void coalesceMulti(uv_work_t* req) {
 
                 uint64_t zxy = (z * POW2_28) + (cover.x * POW2_14) + (cover.y);
 
-                // Reserve stackSize for the coverList. The vector
-                // will grow no larger that the size of the input
-                // subqueries that are being coalesced.
                 std::vector<Cover> covers;
-                covers.reserve(stackSize);
-                covers.push_back(cover);
+                covers.push_back(std::move(cover));
                 uint32_t context_mask = cover.mask;
                 double context_relev = cover.relev;
 
@@ -612,7 +606,7 @@ void coalesceMulti(uv_work_t* req) {
                         }
                     }
                 }
-
+                maxrelev = std::max(maxrelev, context_relev);
                 if (last) {
                     // Slightly penalize contexts that have no stacking
                     if (covers.size() == 1) {
@@ -621,7 +615,9 @@ void coalesceMulti(uv_work_t* req) {
                     } else if (covers[0].mask > covers[1].mask) {
                         context_relev -= 0.01;
                     }
-                    contexts.emplace_back(std::move(covers), context_mask, context_relev);
+                    if (maxrelev - context_relev < .25) {
+                        contexts.emplace_back(std::move(covers), context_mask, context_relev);
+                    }
                 } else if (first || covers.size() > 1) {
                     cit = coalesced.find(zxy);
                     if (cit == coalesced.end()) {
@@ -640,7 +636,9 @@ void coalesceMulti(uv_work_t* req) {
         // append coalesced to contexts by moving memory
         for (auto&& matched : coalesced) {
             for (auto&& context : matched.second) {
-                contexts.emplace_back(std::move(context));
+                if (maxrelev - context.relev < .25) {
+                    contexts.emplace_back(std::move(context));
+                }
             }
         }
 
@@ -720,4 +718,4 @@ void coalesceFinalize(CoalesceBaton* baton, std::vector<Context>&& contexts) {
     }
 }
 
-} // namespace carmen
\ No newline at end of file
+} // namespace carmen
diff --git a/src/cpp_util.hpp b/src/cpp_util.hpp
index c7f55b6..18e43cb 100644
--- a/src/cpp_util.hpp
+++ b/src/cpp_util.hpp
@@ -109,6 +109,12 @@ struct Cover {
     double distance;
     double scoredist;
     bool matches_language;
+
+    Cover() = default;
+    Cover(Cover const& c) = default;
+    Cover& operator=(Cover const& c) = delete;
+    Cover& operator=(Cover&& c) = default;
+    Cover(Cover&& c) = default;
 };
 
 struct Context {
diff --git a/src/rocksdbcache.cpp b/src/rocksdbcache.cpp
index e726a96..b641fa4 100644
--- a/src/rocksdbcache.cpp
+++ b/src/rocksdbcache.cpp
@@ -82,11 +82,11 @@ intarray __getmatching(RocksDBCache const* c, std::string phrase, bool match_pre
 
         if (vals.first != vals.second) {
             value_type unadjusted_lastval = *(vals.first);
-            grids.emplace_back(sortableGrid{
+            grids.emplace_back(
                 vals.first,
                 vals.second,
                 unadjusted_lastval,
-                matches_language});
+                matches_language);
             rh.push(matches_language ? unadjusted_lastval | LANGUAGE_MATCH_BOOST : unadjusted_lastval, grids.size() - 1);
         }
     }
diff --git a/src/rocksdbcache.hpp b/src/rocksdbcache.hpp
index 2a2d924..a1bfcd6 100644
--- a/src/rocksdbcache.hpp
+++ b/src/rocksdbcache.hpp
@@ -30,10 +30,24 @@ namespace carmen {
 #define PREFIX_MAX_GRID_LENGTH 500000
 
 struct sortableGrid {
+    sortableGrid(protozero::const_varint_iterator<uint64_t> _it,
+                 protozero::const_varint_iterator<uint64_t> _end,
+                 value_type _unadjusted_lastval,
+                 bool _matches_language)
+        : it(_it),
+          end(_end),
+          unadjusted_lastval(_unadjusted_lastval),
+          matches_language(_matches_language) {
+    }
     protozero::const_varint_iterator<uint64_t> it;
     protozero::const_varint_iterator<uint64_t> end;
     value_type unadjusted_lastval;
     bool matches_language;
+    sortableGrid() = delete;
+    sortableGrid(sortableGrid const& c) = delete;
+    sortableGrid& operator=(sortableGrid const& c) = delete;
+    sortableGrid& operator=(sortableGrid&& c) = default;
+    sortableGrid(sortableGrid&& c) = default;
 };
 
 struct MergeBaton : carmen::noncopyable {