entry deltas

Author: Gillgamesh

include/sketch/sketch_columns.h

@@ -54,6 +54,10 @@ class FixedSizeSketchColumn {
   void reset_sample_state() {
     //no-op
   };
+  
+  const ColumnEntryDelta generate_entry_delta(vec_t update) const;
+  void apply_entry_delta(const ColumnEntryDelta &delta);
+  
 
   inline bool is_initialized() const {
     return buckets != nullptr;
@@ -113,6 +117,10 @@ FRIEND_TEST(SketchColumnTestSuite, TestUpdateReallocation);
   SketchSample<vec_t> sample() const;
   void clear();
   void update(const vec_t update);
+  
+  const ColumnEntryDelta generate_entry_delta(vec_t update) const;
+  void apply_entry_delta(const ColumnEntryDelta &delta);
+  
   void atomic_update(const vec_t update);
   void merge(ResizeableSketchColumn const& other);
   uint8_t get_depth() const;
@@ -184,6 +192,10 @@ class ResizeableAlignedSketchColumn {
   SketchSample<vec_t> sample() const;
   void clear();
   void update(const vec_t update);
+
+  const ColumnEntryDelta generate_entry_delta(vec_t update) const;
+  void apply_entry_delta(const ColumnEntryDelta &delta);
+
   void atomic_update(const vec_t update) {
     // TODO - implement later
     this->update(update);

include/sketch/sketch_concept.h

@@ -15,6 +15,11 @@ struct SketchSample {
   SampleResult result;
 };
 
+// TODO - figure out how to template this instead of using vec_t
+struct ColumnEntryDelta {
+  Bucket bucket;
+  uint16_t depth;
+};
 
 
 template <typename T = vec_t> requires(std::integral<T>)
@@ -38,6 +43,8 @@ concept ConnectivitySketchConcept = requires(T t, T other) {
 template <typename T, typename V>
 concept SketchColumnConcept = requires(T t, T other) {
   { t.sample() } -> std::same_as<SketchSample<V>>;
+  { t.generate_entry_delta(std::declval<V>()) } -> std::same_as<const ColumnEntryDelta>;
+  { t.apply_entry_delta(std::declval<const ColumnEntryDelta>()) } -> std::same_as<void>;
   { t.update(std::declval<V>()) } -> std::same_as<void>;
   // require an atomic_update function. 
   // up to implementer whether it uses locks or simply atomic XOR 

src/sketch_columns.cpp

@@ -111,6 +111,18 @@ void FixedSizeSketchColumn::update(const vec_t update) {
   deterministic_bucket ^= {update, checksum};
 }
 
+const ColumnEntryDelta FixedSizeSketchColumn::generate_entry_delta(vec_t update) const {
+  vec_hash_t checksum = Bucket_Boruvka::get_index_hash(update, seed);
+  col_hash_t depth = Bucket_Boruvka::get_index_depth_legacy(update, seed, capacity-1);
+  return {Bucket{update, checksum}, static_cast<uint16_t>(depth)};
+}
+
+void FixedSizeSketchColumn::apply_entry_delta(const ColumnEntryDelta &delta) {
+  assert(delta.depth < capacity);
+  buckets[delta.depth] ^= delta.bucket;
+  deterministic_bucket ^= delta.bucket;
+}
+
 void FixedSizeSketchColumn::atomic_update(const vec_t update) {
   vec_hash_t checksum = Bucket_Boruvka::get_index_hash(update, seed);
   col_hash_t depth = Bucket_Boruvka::get_index_depth_legacy(update, seed, capacity-1);
@@ -247,6 +259,23 @@ void ResizeableSketchColumn::update(const vec_t update) {
   buckets[depth] ^= {update, checksum};
 }
 
+const ColumnEntryDelta ResizeableSketchColumn::generate_entry_delta(vec_t update) const {
+  vec_hash_t checksum = Bucket_Boruvka::get_index_hash(update, seed);
+  col_hash_t depth = Bucket_Boruvka::get_index_depth_legacy(update, seed, 60);
+  return {Bucket{update, checksum}, static_cast<uint16_t>(depth)};
+}
+
+void ResizeableSketchColumn::apply_entry_delta(const ColumnEntryDelta &delta) {
+  assert(delta.depth < capacity);
+  deterministic_bucket ^= delta.bucket;
+
+  if (delta.depth >= capacity) {
+    size_t new_capacity = ((delta.depth >> 2) << 2) + 4;
+    reallocate(new_capacity);
+  }
+  buckets[delta.depth] ^= delta.bucket;
+}
+
 void ResizeableSketchColumn::atomic_update(const vec_t update) {
   vec_hash_t checksum = Bucket_Boruvka::get_index_hash(update, seed);
   col_hash_t depth = Bucket_Boruvka::get_index_depth_legacy(update, seed, 60);
@@ -378,6 +407,23 @@ void ResizeableAlignedSketchColumn::update(const vec_t update) {
   aligned_buckets[depth] ^= {update, checksum};
 }
 
+const ColumnEntryDelta ResizeableAlignedSketchColumn::generate_entry_delta(vec_t update) const {
+  vec_hash_t checksum = Bucket_Boruvka::get_index_hash(update, seed);
+  col_hash_t depth = Bucket_Boruvka::get_index_depth_legacy(update, seed, 60);
+  return {Bucket{update, checksum}, static_cast<uint16_t>(depth)};
+}
+
+void ResizeableAlignedSketchColumn::apply_entry_delta(const ColumnEntryDelta &delta) {
+  assert(delta.depth < capacity);
+  deterministic_bucket ^= delta.bucket;
+
+  if (delta.depth >= capacity) {
+    size_t new_capacity = ((delta.depth >> 2) << 2) + 4;
+    reallocate(new_capacity);
+  }
+  aligned_buckets[delta.depth] ^= delta.bucket;
+}
+
 void ResizeableAlignedSketchColumn::merge(ResizeableAlignedSketchColumn const& other) {
   deterministic_bucket ^= other.deterministic_bucket;
   if (other.capacity > capacity) {