From 08d6c84b9d69b500c964a8ff66e726e1f01f2095 Mon Sep 17 00:00:00 2001
From: Douglas Rumbaugh <dbr4@psu.edu>
Date: Mon, 22 May 2023 13:25:20 -0400
Subject: Progress towards generalization of shard interface

---
 include/ds/BloomFilter.h             |  17 +-
 include/framework/DynamicExtension.h | 393 ++++++++++++-----------------------
 include/framework/InternalLevel.h    | 162 ++++-----------
 include/framework/MutableBuffer.h    | 115 ++--------
 include/framework/QueryInterface.h   |  22 ++
 include/framework/ShardInterface.h   |   9 +-
 include/shard/MemISAM.h              |  64 ++----
 include/shard/WIRS.h                 |  75 +++----
 include/util/Record.h                |  34 +--
 9 files changed, 292 insertions(+), 599 deletions(-)
 create mode 100644 include/framework/QueryInterface.h

diff --git a/include/ds/BloomFilter.h b/include/ds/BloomFilter.h
index fddd1fb..d55a7af 100644
--- a/include/ds/BloomFilter.h
+++ b/include/ds/BloomFilter.h
@@ -18,25 +18,28 @@
 
 namespace de {
 
+template <typename K>
 class BloomFilter {
 public:
-    BloomFilter(size_t n_bits, size_t k, const gsl_rng* rng)
+    BloomFilter(size_t n_bits, size_t k)
     : m_n_bits(n_bits), m_n_salts(k), m_bitarray(n_bits) {
+        gsl_rng *rng = gsl_rng_alloc(gsl_rng_mt19937);
         salt = (uint16_t*) aligned_alloc(CACHELINE_SIZE, CACHELINEALIGN(k * sizeof(uint16_t)));
         for (size_t i = 0;  i < k; ++i) {
             salt[i] = (uint16_t) gsl_rng_uniform_int(rng, 1 << 16);
         }
-        
+
+        gsl_rng_free(rng);
     }
 
-    BloomFilter(double max_fpr, size_t n, size_t k, const gsl_rng* rng)
-    : BloomFilter((size_t)(-(double) (k * n) / std::log(1.0 - std::pow(max_fpr, 1.0 / k))), k, rng) {}
+    BloomFilter(double max_fpr, size_t n, size_t k)
+    : BloomFilter((size_t)(-(double) (k * n) / std::log(1.0 - std::pow(max_fpr, 1.0 / k))), k) {}
 
     ~BloomFilter() {
         if (salt) free(salt);
     }
 
-    int insert(const key_t& key, size_t sz = sizeof(key_t)) {
+    int insert(const K& key, size_t sz = sizeof(K)) {
         if (m_bitarray.size() == 0) return 0;
 
         for (size_t i = 0; i < m_n_salts; ++i) {
@@ -46,7 +49,7 @@ public:
         return 1;
     }
 
-    bool lookup(const key_t& key, size_t sz = sizeof(key_t)) {
+    bool lookup(const K& key, size_t sz = sizeof(K)) {
         if (m_bitarray.size() == 0) return false;
         for (size_t i = 0; i < m_n_salts; ++i) {
             if (!m_bitarray.is_set(hash_bytes_with_salt((const char*)&key, sz, salt[i]) % m_n_bits))
@@ -60,7 +63,7 @@ public:
         m_bitarray.clear();
     }
 
-    size_t get_memory_utilization() {
+    size_t get_memory_usage() {
         return this->m_bitarray.mem_size();
     }
 private: 
diff --git a/include/framework/DynamicExtension.h b/include/framework/DynamicExtension.h
index 53b55b1..2009344 100644
--- a/include/framework/DynamicExtension.h
+++ b/include/framework/DynamicExtension.h
@@ -17,6 +17,7 @@
 #include "framework/MutableBuffer.h"
 #include "framework/InternalLevel.h"
 #include "framework/ShardInterface.h"
+#include "framework/QueryInterface.h"
 
 #include "shard/WIRS.h"
 #include "ds/Alias.h"
@@ -71,221 +72,88 @@ enum class DeletePolicy {
 
 typedef ssize_t level_index;
 
-template <RecordInterface R, ShardInterface S>
+template <RecordInterface R, ShardInterface S, QueryInterface Q, typename FQ=void>
 class DynamicExtension {
-    typedef decltype(R::key) K;
-    typedef decltype(R::value) V;
-    typedef decltype(R::weight) W;
 
 public:
-    DynamicExtension(size_t buffer_cap, size_t buffer_delete_cap, size_t scale_factor,
-                     double max_delete_prop, double max_rejection_prop, gsl_rng *rng) 
-        : m_active_buffer(0), 
-          m_scale_factor(scale_factor), 
-          m_max_delete_prop(max_delete_prop),
-          m_max_rejection_rate(max_rejection_prop),
-          m_last_level_idx(-1),
-          m_buffer_1(new MutableBuffer<R>(buffer_cap, LSM_REJ_SAMPLE, buffer_delete_cap, rng)), 
-          m_buffer_2(new MutableBuffer<R>(buffer_cap, LSM_REJ_SAMPLE, buffer_delete_cap, rng)),
-          m_buffer_1_merging(false), m_buffer_2_merging(false) {}
+    DynamicExtension(size_t buffer_cap, size_t scale_factor, double max_delete_prop)
+        : m_scale_factor(scale_factor), m_max_delete_prop(max_delete_prop),
+          m_buffer(new MutableBuffer<R>(buffer_cap, LSM_REJ_SAMPLE, buffer_cap * max_delete_prop))
+    {}
 
     ~DynamicExtension() {
-        delete m_buffer_1;
-        delete m_buffer_2;
+        delete m_buffer;
 
         for (size_t i=0; i<m_levels.size(); i++) {
             delete m_levels[i];
         }
     }
 
-    int delete_record(const K& key, const V& val, gsl_rng *rng) {
-        assert(DELETE_TAGGING);
-
-        auto buffer = get_buffer();
-        // Check the levels first. This assumes there aren't 
-        // any undeleted duplicate records.
-        for (auto level : m_levels) {
-            if (level && level->delete_record(key, val)) {
-                return 1;
-            }
-        }
-
-        // the buffer will take the longest amount of time, and 
-        // probably has the lowest probability of having the record,
-        // so we'll check it last.
-        return buffer->delete_record(key, val);
+    int insert(const R &rec) {
+        return internal_append(rec, false);
     }
 
-    int append(R &rec, gsl_rng *rng) {
-        // NOTE: single-threaded implementation only
+    int erase(const R &rec) {
         MutableBuffer<R> *buffer;
-        while (!(buffer = get_buffer()))
-            ;
-        
-        if (buffer->is_full()) {
-            merge_buffer(rng);
-        }
-
-        return buffer->append(rec);
-    }
-
-    void range_sample(R *sample_set, const K& lower_key, const K& upper_key, size_t sample_sz, gsl_rng *rng) {
-        auto buffer = get_buffer();
-        Alias *buffer_alias = nullptr;
-        std::vector<R *> buffer_records;
-        size_t buffer_cutoff = 0;
-
-        W buffer_weight;
-        if (LSM_REJ_SAMPLE) {
-            buffer_weight = buffer->get_total_weight(); 
-            buffer_cutoff = buffer->get_record_count() - 1;
-        } else {
-            buffer_weight = buffer->get_sample_range(lower_key, upper_key, buffer_records, &buffer_alias, &buffer_cutoff);
-        }
-
-        // Get the shard weights for each level. Index 0 is the buffer,
-        // represented by nullptr.
-        std::vector<std::pair<ShardID, S*>> shards;
-        std::vector<void*> states;
-        shards.push_back({{-1, -1}, nullptr});
-        states.push_back(nullptr);
-
-        std::vector<W> shard_weights;
-        shard_weights.push_back((double) buffer_weight);
-
-        WIRS<R>::wirs_query_parms parms = {lower_key, upper_key};
-
-        for (auto &level : m_levels) {
-            level->get_query_states(shard_weights, shards, states, &parms);
-        }
 
-        if (shard_weights.size() == 1 && shard_weights[0] == 0) {
-            if (buffer_alias) delete buffer_alias;
-            for (auto& x: states) S::delete_query_state(x);
-            sampling_bailouts++;
-            return; // no records in the sampling range
-        }
-
-        double tot_weight = std::accumulate(shard_weights.begin(), shard_weights.end(), 0);
-        std::vector<double> normalized_weights(shard_weights.size());
-        for (size_t i=0; i<shard_weights.size(); i++) {
-            normalized_weights[i] = ((double) shard_weights[i]) / tot_weight;
-        }
-
-        // Construct alias structure
-        auto alias = Alias(normalized_weights);
-
-        std::vector<size_t> shard_samples(shard_weights.size(), 0);
-
-        size_t rejections = sample_sz;
-        size_t sample_idx = 0;
-
-        size_t buffer_rejections = 0;
-        
-        do {
-            for (size_t i=0; i<rejections; i++) {
-                shard_samples[alias.get(rng)] += 1;
-            }
-
-            rejections = 0;
-
-            while (shard_samples[0] > 0) {
-                const R *rec;
-                if (LSM_REJ_SAMPLE) {
-                    rec = buffer->get_sample(lower_key, upper_key, rng);
-                } else {
-                    rec = buffer_records[buffer_alias->get(rng)];
-                }
+        if constexpr (DELETE_TAGGING) {
+            auto buffer = get_buffer();
 
-                if (DELETE_TAGGING) {
-                    if (rec && !rec->is_deleted()) {
-                        sample_set[sample_idx++] = *rec;
-                    } else {
-                        rejections++;
-                    }
-                } else {
-                    if (rec && !buffer->check_tombstone(*rec)) {
-                        sample_set[sample_idx++] = *rec;
-                    } else {
-                        rejections++;
-                    }
-                }
-
-                shard_samples[0]--;
-
-                // Assume nothing in buffer and bail out.
-                // FIXME: rather than a bailout, we could switch to non-rejection 
-                // sampling, but that would require rebuilding the full alias structure. 
-                // Wouldn't be too hard to do, but for the moment I'll just do this.
-                if (LSM_REJ_SAMPLE && buffer_rejections >= sample_sz && sample_idx == 0 && shard_weights.size() == 1) {
-                    if (buffer_alias) delete buffer_alias;
-                    //for (auto& x: states) delete x;
-                    sampling_bailouts++;
-                    return; // no records in the sampling range
+            // Check the levels first. This assumes there aren't 
+            // any undeleted duplicate records.
+            for (auto level : m_levels) {
+                if (level && level->delete_record(rec)) {
+                    return 1;
                 }
             }
 
-            std::vector<R> results;
-            for (size_t i=1; i<shard_samples.size(); i++) {
-                results.reserve(shard_samples[i]);
-
-                shards[i].second->get_samples(states[i], results, lower_key, upper_key, shard_samples[i], rng);
+            // the buffer will take the longest amount of time, and 
+            // probably has the lowest probability of having the record,
+            // so we'll check it last.
+            return buffer->delete_record(rec);
+        }
 
-                for (size_t j=0; j<results.size(); j++) {
-                    if (rejection(results[j], shards[i].first, lower_key, upper_key, buffer, buffer_cutoff)) {
-                        rejections++;
-                        continue;
-                    }
+        return internal_append(rec, true);
+    }
 
-                    sample_set[sample_idx++] = results[j]; 
-                }
+    std::vector<R> query(void *parms) {
 
-                shard_samples[i] = 0;
-                results.clear();
-            }
+        // Use the provided top-level query function is one 
+        // is specified. Otherwise, use the default framework
+        // behavior.
+        if constexpr (!std::is_same<FQ, void>::value) {
+            return FQ(parms);
+        }
 
-        } while (sample_idx < sample_sz);
+        auto buffer = get_buffer();
 
-        if (buffer_alias) delete buffer_alias;
-        for (auto& x: states) S::delete_query_state(x);
+        // Get the buffer query state
+        auto buffer_state = Q::get_buffer_query_state(buffer, parms);
 
-        enforce_rejection_rate_maximum(rng);
-    }
+        // Get the shard query states
+        std::vector<std::pair<ShardID, S*>> shards;
+        std::vector<void*> states;
 
-    // Checks the tree and buffer for a tombstone corresponding to
-    // the provided record in any shard *above* the shid, which
-    // should correspond to the shard containing the record in question
-    // 
-    // Passing INVALID_SHID indicates that the record exists within the buffer
-    bool is_deleted(const R &record, const ShardID &shid, MutableBuffer<R> *buffer, size_t buffer_cutoff) {
-        // If tagging is enabled, we just need to check if the record has the delete tag set
-        if (DELETE_TAGGING) {
-            return record.is_deleted();
+        for (auto &level : m_levels) {
+            level->get_query_states(shards, states, parms);
         }
 
-        // Otherwise, we need to look for a tombstone.
-
-        // check for tombstone in the buffer. This will require accounting for the cutoff eventually.
-        if (buffer->check_tombstone(record)) {
-            return true;
-        }
+        std::vector<std::vector<R>> query_results(shards.size() + 1);
 
-        // if the record is in the buffer, then we're done.
-        if (shid == INVALID_SHID) {
-            return false;
-        }
+        // Execute the query for the buffer
+        query_results[0] = Q::buffer_query(buffer, buffer_state, parms);
 
-        for (size_t lvl=0; lvl<=shid.level_idx; lvl++) {
-            if (m_levels[lvl]->check_tombstone(0, record)) {
-                return true;
-            }
+        // Execute the query for each shard
+        for (size_t i=0; i<shards.size(); i++) {
+           query_results[i] = post_process(Q::query(shards[i].second, states[i], parms));
         }
+        
+        // Merge the results together
+        auto result = Q::merge(query_results);
 
-        // check the level containing the shard
-        return m_levels[shid.level_idx]->check_tombstone(shid.shard_idx + 1, record);
+        return result;
     }
 
-
     size_t get_record_cnt() {
         size_t cnt = get_buffer()->get_record_count();
 
@@ -296,7 +164,6 @@ public:
         return cnt;
     }
 
-
     size_t get_tombstone_cnt() {
         size_t cnt = get_buffer()->get_tombstone_count();
 
@@ -311,22 +178,22 @@ public:
         return m_levels.size();
     }
 
-    size_t get_memory_utilization() {
-        size_t cnt = m_buffer_1->get_memory_utilization() + m_buffer_2->get_memory_utilization();
+    size_t get_memory_usage() {
+        size_t cnt = m_buffer->get_memory_usage();
 
         for (size_t i=0; i<m_levels.size(); i++) {
-            if (m_levels[i]) cnt += m_levels[i]->get_memory_utilization();
+            if (m_levels[i]) cnt += m_levels[i]->get_memory_usage();
         }
 
         return cnt;
     }
 
-    size_t get_aux_memory_utilization() {
-        size_t cnt = m_buffer_1->get_aux_memory_utilization() + m_buffer_2->get_aux_memory_utilization();
+    size_t get_aux_memory_usage() {
+        size_t cnt = m_buffer->get_aux_memory_usage();
 
         for (size_t i=0; i<m_levels.size(); i++) {
             if (m_levels[i]) {
-                cnt += m_levels[i]->get_aux_memory_utilization();
+                cnt += m_levels[i]->get_aux_memory_usage();
             }
         }
 
@@ -348,10 +215,9 @@ public:
     }
 
     size_t get_buffer_capacity() {
-        return m_buffer_1->get_capacity();
+        return m_buffer->get_capacity();
     }
     
-
     S *create_ssi() {
         std::vector<S *> shards;
 
@@ -384,57 +250,72 @@ public:
     }
 
 private:
-    MutableBuffer<R> *m_buffer_1;
-    MutableBuffer<R> *m_buffer_2;
-    std::atomic<bool> m_active_buffer;
-    std::atomic<bool> m_buffer_1_merging;
-    std::atomic<bool> m_buffer_2_merging;
+    MutableBuffer<R> *m_buffer;
 
     size_t m_scale_factor;
     double m_max_delete_prop;
-    double m_max_rejection_rate;
 
-    std::vector<InternalLevel<R, S> *> m_levels;
-
-    level_index m_last_level_idx;
+    std::vector<InternalLevel<R, S, Q> *> m_levels;
 
     MutableBuffer<R> *get_buffer() {
-        if (m_buffer_1_merging && m_buffer_2_merging) {
-            return nullptr;
-        }
-
-        return (m_active_buffer) ? m_buffer_2 : m_buffer_1;
+        return m_buffer;
     }
 
-    inline bool rejection(const R &record, ShardID shid, const K& lower_bound, const K& upper_bound, MutableBuffer<R> *buffer, size_t buffer_cutoff) {
-        if (record.is_tombstone()) {
-            tombstone_rejections++;
-            return true;
-        } else if (record.key < lower_bound || record.key > upper_bound) {
-            bounds_rejections++;
-            return true;
-        } else if (is_deleted(record, shid, buffer, buffer_cutoff)) {
-            deletion_rejections++;
-            return true;
+    int internal_append(R &rec, bool ts) {
+        MutableBuffer<R> *buffer;
+        while (!(buffer = get_buffer()))
+            ;
+        
+        if (buffer->is_full()) {
+            merge_buffer();
         }
 
-        return false;
+        return buffer->append(rec, ts);
     }
 
-    inline bool add_to_sample(const R &record, ShardID shid, const K& upper_key, const K& lower_key, char *io_buffer,
-                              R *sample_buffer, size_t &sample_idx, MutableBuffer<R> *buffer, size_t buffer_cutoff) {
-        TIMER_INIT();
-        TIMER_START();
-        sampling_attempts++;
-        if (!record || rejection(record, shid, lower_key, upper_key, io_buffer, buffer, buffer_cutoff)) {
-            sampling_rejections++;
-            return false;
+    std::vector<R> post_process(std::vector<R> records, ShardID shid, MutableBuffer<R> *buffer) {
+        std::vector<R> processed_records;
+        processed_records.reserve(records.size());
+
+        // For delete tagging, we just need to check the delete bit on each
+        // record.
+        if constexpr (DELETE_TAGGING) {
+            for (auto &rec : records) {
+                if (rec.is_deleted()) {
+                    continue;
+                }
+
+                processed_records.emplace_back(rec.rec);
+            }
+
+            return processed_records;
         }
-        TIMER_STOP();
-        rejection_check_time += TIMER_RESULT();
 
-        sample_buffer[sample_idx++] = *record;
-        return true;
+        // For tombstone deletes, we need to search for the corresponding 
+        // tombstone for each record.
+        for (auto &rec : records) {
+           if (rec.is_tombstone()) {
+                continue;
+            } 
+
+            if (buffer->check_tombstone(rec.rec)) {
+                continue;
+            }
+
+            if (shid != INVALID_SHID) {
+                for (size_t lvl=0; lvl<=shid.level_idx; lvl++) {
+                    if (m_levels[lvl]->check_tombstone(0, rec.rec)) {
+                        continue;
+                    }
+                }
+
+                if (m_levels[shid.level_idx]->check_tombstone(shid.shard_idx + 1, rec.rec)) {
+                    continue;
+                }
+            }
+
+            processed_records.emplace_back(rec.rec);
+        }
     }
 
     /*
@@ -450,24 +331,23 @@ private:
         if (new_idx > 0) {
             assert(m_levels[new_idx - 1]->get_shard(0)->get_tombstone_count() == 0);
         }
-        m_levels.emplace_back(new InternalLevel<R, S>(new_idx, new_shard_cnt));
+        m_levels.emplace_back(new InternalLevel<R, S, Q>(new_idx, new_shard_cnt));
 
-        m_last_level_idx++;
         return new_idx;
     }
 
 
     // Merge the memory table down into the tree, completing any required other
     // merges to make room for it.
-    inline void merge_buffer(gsl_rng *rng) {
+    inline void merge_buffer() {
         auto buffer = get_buffer();
 
         if (!can_merge_with(0, buffer->get_record_count())) {
-            merge_down(0, rng);
+            merge_down(0);
         }
 
-        merge_buffer_into_l0(buffer, rng);
-        enforce_delete_maximum(0, rng);
+        merge_buffer_into_l0(buffer);
+        enforce_delete_maximum(0);
 
         buffer->truncate();
         return;
@@ -479,15 +359,15 @@ private:
      * routine will recursively perform any necessary merges to make room for the 
      * specified level.
      */
-    inline void merge_down(level_index idx, gsl_rng *rng) {
+    inline void merge_down(level_index idx) {
         level_index merge_base_level = find_mergable_level(idx);
         if (merge_base_level == -1) {
             merge_base_level = grow();
         }
 
         for (level_index i=merge_base_level; i>idx; i--) {
-            merge_levels(i, i-1, rng);
-            enforce_delete_maximum(i, rng);
+            merge_levels(i, i-1);
+            enforce_delete_maximum(i);
         }
 
         return;
@@ -509,7 +389,7 @@ private:
         level_index merge_level_idx;
 
         size_t incoming_rec_cnt = get_level_record_count(idx, buffer);
-        for (level_index i=idx+1; i<=m_last_level_idx; i++) {
+        for (level_index i=idx+1; i<=m_levels.size(); i++) {
             if (can_merge_with(i, incoming_rec_cnt)) {
                 return i;
             }
@@ -526,35 +406,35 @@ private:
      * are skipped in the merge process--otherwise the tombstone ordering
      * invariant may be violated by the merge operation.
      */
-    inline void merge_levels(level_index base_level, level_index incoming_level, gsl_rng *rng) {
+    inline void merge_levels(level_index base_level, level_index incoming_level) {
         // merging two memory levels
         if (LSM_LEVELING) {
             auto tmp = m_levels[base_level];
-            m_levels[base_level] = InternalLevel<R, S>::merge_levels(m_levels[base_level], m_levels[incoming_level], rng);
+            m_levels[base_level] = InternalLevel<R, S, Q>::merge_levels(m_levels[base_level], m_levels[incoming_level]);
             mark_as_unused(tmp);
         } else {
-            m_levels[base_level]->append_merged_shards(m_levels[incoming_level], rng);
+            m_levels[base_level]->append_merged_shards(m_levels[incoming_level]);
         }
 
         mark_as_unused(m_levels[incoming_level]);
-        m_levels[incoming_level] = new InternalLevel<R, S>(incoming_level, (LSM_LEVELING) ? 1 : m_scale_factor);
+        m_levels[incoming_level] = new InternalLevel<R, S, Q>(incoming_level, (LSM_LEVELING) ? 1 : m_scale_factor);
     }
 
 
-    inline void merge_buffer_into_l0(MutableBuffer<R> *buffer, gsl_rng *rng) {
+    inline void merge_buffer_into_l0(MutableBuffer<R> *buffer) {
         assert(m_levels[0]);
         if (LSM_LEVELING) {
             // FIXME: Kludgey implementation due to interface constraints.
             auto old_level = m_levels[0];
-            auto temp_level = new InternalLevel<R, S>(0, 1);
-            temp_level->append_mem_table(buffer, rng);
-            auto new_level = InternalLevel<R, S>::merge_levels(old_level, temp_level, rng);
+            auto temp_level = new InternalLevel<R, S, Q>(0, 1);
+            temp_level->append_buffer(buffer);
+            auto new_level = InternalLevel<R, S, Q>::merge_levels(old_level, temp_level);
 
             m_levels[0] = new_level;
             delete temp_level;
             mark_as_unused(old_level);
         } else {
-            m_levels[0]->append_mem_table(buffer, rng);
+            m_levels[0]->append_buffer(buffer);
         }
     }
 
@@ -564,7 +444,7 @@ private:
      * level may not be able to immediately be deleted, depending upon who
      * else is using it.
      */ 
-    inline void mark_as_unused(InternalLevel<R, S> *level) {
+    inline void mark_as_unused(InternalLevel<R, S, Q> *level) {
         delete level;
     }
 
@@ -573,31 +453,16 @@ private:
      * if the limit is exceeded, forcibly merge levels until all
      * levels below idx are below the limit.
      */
-    inline void enforce_delete_maximum(level_index idx, gsl_rng *rng) {
+    inline void enforce_delete_maximum(level_index idx) {
         long double ts_prop = (long double) m_levels[idx]->get_tombstone_count() / (long double) calc_level_record_capacity(idx);
 
         if (ts_prop > (long double) m_max_delete_prop) {
-            merge_down(idx, rng);
+            merge_down(idx);
         }
 
         return;
     }
 
-    inline void enforce_rejection_rate_maximum(gsl_rng *rng) {
-        if (m_levels.size() == 0) {
-            return;
-        }
-
-        for (size_t i=0; i<m_last_level_idx; i++) {
-            if (m_levels[i]) {
-                double ratio = m_levels[i]->get_rejection_rate();
-                if (ratio > m_max_rejection_rate) {
-                    merge_down(i, rng);
-                }
-            }
-        } 
-    }
-
     /*
      * Assume that level "0" should be larger than the buffer. The buffer
      * itself is index -1, which should return simply the buffer capacity.
diff --git a/include/framework/InternalLevel.h b/include/framework/InternalLevel.h
index 18b7de3..70da821 100644
--- a/include/framework/InternalLevel.h
+++ b/include/framework/InternalLevel.h
@@ -16,85 +16,52 @@
 #include "util/bf_config.h"
 #include "framework/ShardInterface.h"
 #include "framework/MutableBuffer.h"
+#include "framework/QueryInterface.h"
 #include "ds/BloomFilter.h"
 
 namespace de {
 
-template <RecordInterface R, ShardInterface S>
+template <RecordInterface R, ShardInterface S, QueryInterface Q>
 class InternalLevel {
 
-    static const size_t REJECTION_TRIGGER_THRESHOLD = 1024;
-
-    typedef decltype(R::key) K;
-    typedef decltype(R::value) V;
-    //typedef WIRS<R> S;
-
-private:
-    struct InternalLevelStructure {
-        InternalLevelStructure(size_t cap)
-        : m_cap(cap)
-        , m_shards(new S*[cap]{nullptr})
-        , m_bfs(new BloomFilter*[cap]{nullptr}) {} 
-
-        ~InternalLevelStructure() {
-            for (size_t i = 0; i < m_cap; ++i) {
-                if (m_shards[i]) delete m_shards[i];
-                if (m_bfs[i]) delete m_bfs[i];
-            }
-
-            delete[] m_shards;
-            delete[] m_bfs;
-        }
-
-        size_t m_cap;
-        S** m_shards;
-        BloomFilter** m_bfs;
-    };
-
 public:
     InternalLevel(ssize_t level_no, size_t shard_cap)
-    : m_level_no(level_no), m_shard_cnt(0)
-    , m_structure(new InternalLevelStructure(shard_cap)) {}
+    : m_level_no(level_no), m_shard_cnt(0), m_shards(new std::vector<S>(shard_cap, nullptr))
+    {}
 
     // Create a new memory level sharing the shards and repurposing it as previous level_no + 1
     // WARNING: for leveling only.
     InternalLevel(InternalLevel* level)
     : m_level_no(level->m_level_no + 1), m_shard_cnt(level->m_shard_cnt)
-    , m_structure(level->m_structure) {
-        assert(m_structure->m_cap == 1 && m_shard_cnt == 1);
+    , m_shards(level->m_shards) {
+        assert(m_shard_cnt == 1 && m_shards.size() == 1);
     }
 
     ~InternalLevel() {}
 
     // WARNING: for leveling only.
     // assuming the base level is the level new level is merging into. (base_level is larger.)
-    static InternalLevel* merge_levels(InternalLevel* base_level, InternalLevel* new_level, const gsl_rng* rng) {
+    static InternalLevel* merge_levels(InternalLevel* base_level, InternalLevel* new_level) {
         assert(base_level->m_level_no > new_level->m_level_no || (base_level->m_level_no == 0 && new_level->m_level_no == 0));
         auto res = new InternalLevel(base_level->m_level_no, 1);
         res->m_shard_cnt = 1;
-        res->m_structure->m_bfs[0] =
-            new BloomFilter(BF_FPR,
-                            new_level->get_tombstone_count() + base_level->get_tombstone_count(),
-                            BF_HASH_FUNCS, rng);
         S* shards[2];
-        shards[0] = base_level->m_structure->m_shards[0];
-        shards[1] = new_level->m_structure->m_shards[0];
+        shards[0] = base_level->m_shards[0];
+        shards[1] = new_level->m_shards[0];
 
-        res->m_structure->m_shards[0] = new S(shards, 2, res->m_structure->m_bfs[0]);
+        res->m_shards[0] = new S(shards, 2);
         return res;
     }
 
-    void append_mem_table(MutableBuffer<R>* buffer, const gsl_rng* rng) {
-        assert(m_shard_cnt < m_structure->m_cap);
-        m_structure->m_bfs[m_shard_cnt] = new BloomFilter(BF_FPR, buffer->get_tombstone_count(), BF_HASH_FUNCS, rng);
-        m_structure->m_shards[m_shard_cnt] = new S(buffer, m_structure->m_bfs[m_shard_cnt]);
+    void append_buffer(MutableBuffer<R>* buffer) {
+        assert(m_shard_cnt < m_shards.size());
+        m_shards[m_shard_cnt] = new S(buffer);
         ++m_shard_cnt;
     }
 
-    void append_merged_shards(InternalLevel* level, const gsl_rng* rng) {
-        assert(m_shard_cnt < m_structure->m_cap);
-        m_structure->m_bfs[m_shard_cnt] = new BloomFilter(BF_FPR, level->get_tombstone_count(), BF_HASH_FUNCS, rng);
-        m_structure->m_shards[m_shard_cnt] = new S(level->m_structure->m_shards, level->m_shard_cnt, m_structure->m_bfs[m_shard_cnt]);
+    void append_merged_shards(InternalLevel* level) {
+        assert(m_shard_cnt < m_shards.size());
+        m_shards[m_shard_cnt] = new S(level->m_shards, level->m_shard_cnt);
         ++m_shard_cnt;
     }
 
@@ -102,50 +69,36 @@ public:
         S *shards[m_shard_cnt];
 
         for (size_t i=0; i<m_shard_cnt; i++) {
-            shards[i] = (m_structure->m_shards[i]) ? m_structure->m_shards[i] : nullptr;
+            shards[i] = m_shards[i];
         }
 
-        return new S(shards, m_shard_cnt, nullptr);
+        return new S(shards, m_shard_cnt);
     }
 
     // Append the sample range in-order.....
-    void get_query_states(std::vector<uint64_t>& weights, std::vector<std::pair<ShardID, S *>> &shards, std::vector<void*>& shard_states, void *query_parms) {
+    void get_query_states(std::vector<std::pair<ShardID, S *>> &shards, std::vector<void*>& shard_states, void *query_parms) {
         for (size_t i=0; i<m_shard_cnt; i++) {
-            if (m_structure->m_shards[i]) {
-                auto shard_state = m_structure->m_shards[i]->get_query_state(query_parms);
-                if (shard_state->tot_weight > 0) {
-                    shards.push_back({{m_level_no, (ssize_t) i}, m_structure->m_shards[i]});
-                    weights.push_back(shard_state->tot_weight);
-                    shard_states.emplace_back(shard_state);
-                } else {
-                    S::delete_state(shard_state);
-                }
+            if (m_shards[i]) {
+                auto shard_state = Q::get_query_state(m_shards[i], query_parms);
+                shards.push_back({{m_level_no, (ssize_t) i}, m_shards[i]});
+                shard_states.emplace_back(shard_state);
             }
         }
     }
 
-    bool bf_rejection_check(size_t shard_stop, const K& key) {
-        for (size_t i = 0; i < shard_stop; ++i) {
-            if (m_structure->m_bfs[i] && m_structure->m_bfs[i]->lookup(key))
-                return true;
-        }
-        return false;
-    }
-
     bool check_tombstone(size_t shard_stop, const R& rec) {
         if (m_shard_cnt == 0) return false;
 
         for (int i = m_shard_cnt - 1; i >= (ssize_t) shard_stop;  i--) {
-            if (m_structure->m_shards[i] && (m_structure->m_bfs[i]->lookup(rec.key))
-                && m_structure->m_shards[i]->check_tombstone(rec))
+            if (m_shards[i] && m_shards[i]->check_tombstone(rec))
                 return true;
         }
         return false;
     }
 
-    bool delete_record(const K& key, const V& val) {
-        for (size_t i = 0; i < m_structure->m_cap;  ++i) {
-            if (m_structure->m_shards[i] && m_structure->m_shards[i]->delete_record(key, val)) {
+    bool delete_record(const R &rec) {
+        for (size_t i = 0; i < m_shards.size();  ++i) {
+            if (m_shards[i] && m_shards[i]->delete_record(rec)) {
                 return true;
             }
         }
@@ -153,12 +106,8 @@ public:
         return false;
     }
 
-    const R* get_record_at(size_t shard_no, size_t idx) {
-        return m_structure->m_shards[shard_no]->get_record_at(idx);
-    }
-    
     S* get_shard(size_t idx) {
-        return m_structure->m_shards[idx];
+        return m_shards[idx];
     }
 
     size_t get_shard_count() {
@@ -168,7 +117,7 @@ public:
     size_t get_record_cnt() {
         size_t cnt = 0;
         for (size_t i=0; i<m_shard_cnt; i++) {
-            cnt += m_structure->m_shards[i]->get_record_count();
+            cnt += m_shards[i]->get_record_count();
         }
 
         return cnt;
@@ -177,27 +126,25 @@ public:
     size_t get_tombstone_count() {
         size_t res = 0;
         for (size_t i = 0; i < m_shard_cnt; ++i) {
-            res += m_structure->m_shards[i]->get_tombstone_count();
+            res += m_shards[i]->get_tombstone_count();
         }
         return res;
     }
 
-    size_t get_aux_memory_utilization() {
+    size_t get_aux_memory_usage() {
         size_t cnt = 0;
         for (size_t i=0; i<m_shard_cnt; i++) {
-            if (m_structure->m_bfs[i]) {
-                cnt += m_structure->m_bfs[i]->get_memory_utilization();
-            }
+            cnt += m_shards[i]->get_aux_memory_usage();
         }
 
         return cnt;
     }
 
-    size_t get_memory_utilization() {
+    size_t get_memory_usage() {
         size_t cnt = 0;
         for (size_t i=0; i<m_shard_cnt; i++) {
-            if (m_structure->m_shards[i]) {
-                cnt += m_structure->m_shards[i]->get_memory_utilization();
+            if (m_shards[i]) {
+                cnt += m_shards[i]->get_memory_usage();
             }
         }
 
@@ -208,51 +155,22 @@ public:
         size_t tscnt = 0;
         size_t reccnt = 0;
         for (size_t i=0; i<m_shard_cnt; i++) {
-            if (m_structure->m_shards[i]) {
-                tscnt += m_structure->m_shards[i]->get_tombstone_count();
-                reccnt += m_structure->m_shards[i]->get_record_count();
+            if (m_shards[i]) {
+                tscnt += m_shards[i]->get_tombstone_count();
+                reccnt += m_shards[i]->get_record_count();
             }
         }
 
         return (double) tscnt / (double) (tscnt + reccnt);
     }
 
-    size_t get_rejection_count() {
-        size_t rej_cnt = 0;
-        for (size_t i=0; i<m_shard_cnt; i++) {
-            if (m_structure->m_shards[i]) {
-                rej_cnt += m_structure->m_shards[i]->get_rejection_count();
-            }
-        }
-
-        return rej_cnt;
-    }
-
-    double get_rejection_rate() {
-        size_t rej_cnt = 0;
-        size_t attempt_cnt = 0;
-        for (size_t i=0; i<m_shard_cnt; i++) {
-            if (m_structure->m_shards[i]) {
-                attempt_cnt += m_structure->m_shards[i]->get_ts_check_count();
-                rej_cnt += m_structure->m_shards[i]->get_rejection_count();
-            }
-        }
-
-        if (attempt_cnt == 0) return 0;
-
-        // the rejection rate is considered 0 until we exceed an
-        // absolute threshold of rejections.
-        if (rej_cnt <= REJECTION_TRIGGER_THRESHOLD) return 0;
-
-        return (double) rej_cnt / (double) attempt_cnt;
-    }
-
 private:
     ssize_t m_level_no;
     
     size_t m_shard_cnt;
     size_t m_shard_size_cap;
-    std::shared_ptr<InternalLevelStructure> m_structure;
+
+    std::shared_ptr<std::vector<S*>> m_shards;
 };
 
 }
diff --git a/include/framework/MutableBuffer.h b/include/framework/MutableBuffer.h
index 74838b8..4b45f20 100644
--- a/include/framework/MutableBuffer.h
+++ b/include/framework/MutableBuffer.h
@@ -28,17 +28,17 @@ namespace de {
 
 template <RecordInterface R>
 class MutableBuffer {
+    typedef WrappedRecord<R> WRec;
 public:
-    MutableBuffer(size_t capacity, bool rej_sampling, size_t max_tombstone_cap, const gsl_rng* rng)
+    MutableBuffer(size_t capacity, bool rej_sampling, size_t max_tombstone_cap)
     : m_cap(capacity), m_tombstone_cap(max_tombstone_cap), m_reccnt(0)
     , m_tombstonecnt(0), m_weight(0), m_max_weight(0) {
-        auto len = capacity * sizeof(R);
+        auto len = capacity * sizeof(WRec);
         size_t aligned_buffersize = len + (CACHELINE_SIZE - (len % CACHELINE_SIZE));
-        m_data = (R*) std::aligned_alloc(CACHELINE_SIZE, aligned_buffersize);
+        m_data = (WRec*) std::aligned_alloc(CACHELINE_SIZE, aligned_buffersize);
         m_tombstone_filter = nullptr;
         if (max_tombstone_cap > 0) {
-            assert(rng != nullptr);
-            m_tombstone_filter = new BloomFilter(BF_FPR, max_tombstone_cap, BF_HASH_FUNCS, rng);
+            m_tombstone_filter = new BloomFilter<R>(BF_FPR, max_tombstone_cap, BF_HASH_FUNCS);
         }
     }
 
@@ -48,18 +48,23 @@ public:
     }
 
     template <typename R_ = R>
-    int append(const R &rec) {
-        if (rec.is_tombstone() && m_tombstonecnt + 1 > m_tombstone_cap) return 0;
+    int append(const R &rec, bool tombstone=false) {
+        if (tombstone && m_tombstonecnt + 1 > m_tombstone_cap) return 0;
 
         int32_t pos = 0;
         if ((pos = try_advance_tail()) == -1) return 0;
 
-        m_data[pos] = rec;
+        WRec wrec;
+        wrec.rec = rec;
+
+        if (tombstone) wrec.set_tombstone();
+
+        m_data[pos] = wrec;
         m_data[pos].header |= (pos << 2);
 
-        if (rec.is_tombstone()) {
+        if (tombstone) {
             m_tombstonecnt.fetch_add(1);
-            if (m_tombstone_filter) m_tombstone_filter->insert(rec.key);
+            if (m_tombstone_filter) m_tombstone_filter->insert(rec);
         }
 
         if constexpr (WeightedRecordInterface<R_>) {
@@ -86,18 +91,6 @@ public:
         return true;
     }
 
-    R* sorted_output() {
-        TIMER_INIT();
-        TIMER_START();
-        std::sort(m_data, m_data + m_reccnt.load(), memtable_record_cmp<R>);
-        TIMER_STOP();
-
-        #ifdef INSTRUMENT_MERGING
-        fprintf(stderr, "sort\t%ld\n", TIMER_RESULT());
-        #endif
-        return m_data;
-    }
-    
     size_t get_record_count() {
         return m_reccnt;
     }
@@ -117,7 +110,7 @@ public:
     bool delete_record(const R& rec) {
         auto offset = 0;
         while (offset < m_reccnt.load()) {
-            if (m_data[offset] == rec) {
+            if (m_data[offset].rec == rec) {
                 m_data[offset].set_delete();
                 return true;
             }
@@ -128,11 +121,11 @@ public:
     }
 
     bool check_tombstone(const R& rec) {
-        if (m_tombstone_filter && !m_tombstone_filter->lookup(rec.key)) return false;
+        if (m_tombstone_filter && !m_tombstone_filter->lookup(rec)) return false;
 
         auto offset = 0;
         while (offset < m_reccnt.load()) {
-            if (m_data[offset] == rec && m_data[offset].is_tombstone()) {
+            if (m_data[offset].rec == rec && m_data[offset].is_tombstone()) {
                 return true;
             }
             offset++;;
@@ -140,73 +133,12 @@ public:
         return false;
     }
 
-    const R* get_record_at(size_t idx) {
-        return m_data + idx;
-    }
-
-    size_t get_memory_utilization() {
+    size_t get_memory_usage() {
         return m_cap * sizeof(R);
     }
 
-    size_t get_aux_memory_utilization() {
-        return m_tombstone_filter->get_memory_utilization();
-    }
-    //
-    // NOTE: This operation samples from records strictly between the upper and
-    // lower bounds, not including them
-    template <typename R_ = R>
-    double get_sample_range(const decltype(R_::key) lower, const decltype(R_::key)& upper, 
-                            std::vector<R *> &records, Alias **alias, size_t *cutoff) {
-      std::vector<double> weights;
-
-      *cutoff = std::atomic_load(&m_reccnt) - 1;
-      records.clear();
-      double tot_weight = 0.0;
-      for (size_t i = 0; i < (*cutoff) + 1; i++) {
-        R *rec = m_data + i;
-
-        if (rec->key >= lower && rec->key <= upper && !rec->is_tombstone() && !rec->is_deleted()) {
-          weights.push_back(rec->weight);
-          records.push_back(rec);
-          tot_weight += rec->weight;
-        }
-      }
-
-      for (size_t i = 0; i < weights.size(); i++) {
-        weights[i] = weights[i] / tot_weight;
-      }
-
-      *alias = new Alias(weights);
-
-      return tot_weight;
-    }
-
-    // rejection sampling
-    template <typename R_ = R>
-    const R *get_sample(const decltype(R_::key)& lower, const decltype(R_::key)& upper, gsl_rng *rng) {
-        size_t reccnt = m_reccnt.load();
-        if (reccnt == 0) {
-            return nullptr;
-        }
-
-        auto idx = (reccnt == 1) ? 0 : gsl_rng_uniform_int(rng, reccnt - 1);
-        auto rec = get_record_at(idx);
-
-        auto test = gsl_rng_uniform(rng) * m_max_weight.load();
-
-        if (test > rec->weight) {
-            return nullptr;
-        }
-
-        if (test <= rec->weight &&
-          rec->key >= lower &&
-          rec->key <= upper && 
-          !rec->is_tombstone() && !rec->is_deleted()) {
-
-            return rec;
-        }
-
-        return nullptr;
+    size_t get_aux_memory_usage() {
+        return m_tombstone_filter->get_memory_usage();
     }
 
     size_t get_tombstone_capacity() {
@@ -226,15 +158,12 @@ private:
     }
 
     size_t m_cap;
-    //size_t m_buffersize;
     size_t m_tombstone_cap;
     
-    //char* m_data;
     R* m_data;
-    BloomFilter* m_tombstone_filter;
+    BloomFilter<R>* m_tombstone_filter;
 
     alignas(64) std::atomic<size_t> m_tombstonecnt;
-    //alignas(64) std::atomic<uint32_t> m_current_tail;
     alignas(64) std::atomic<uint32_t> m_reccnt;
     alignas(64) std::atomic<double> m_weight;
     alignas(64) std::atomic<double> m_max_weight;
diff --git a/include/framework/QueryInterface.h b/include/framework/QueryInterface.h
new file mode 100644
index 0000000..eafeeb0
--- /dev/null
+++ b/include/framework/QueryInterface.h
@@ -0,0 +1,22 @@
+/*
+ * include/framework/QueryInterface.h
+ *
+ * Copyright (C) 2023 Douglas Rumbaugh <drumbaugh@psu.edu> 
+ *
+ * All rights reserved. Published under the Modified BSD License.
+ *
+ */
+#pragma once
+
+#include <concepts>
+#include "util/types.h"
+
+template <typename Q>
+concept QueryInterface = requires(Q q, void *p) {
+    {q.get_query_state(p, p)} -> std::convertible_to<void*>;
+    {q.get_buffer_query_state(p, p)};
+    {q.query(p, p)};
+    {q.buffer_query(p, p)};
+    {q.merge()};
+    {q.delete_query_state(p)};
+};
diff --git a/include/framework/ShardInterface.h b/include/framework/ShardInterface.h
index 5d07a99..1f48a45 100644
--- a/include/framework/ShardInterface.h
+++ b/include/framework/ShardInterface.h
@@ -1,5 +1,5 @@
 /*
- * include/shard/ShardInterface.h
+ * include/framework/ShardInterface.h
  *
  * Copyright (C) 2023 Douglas Rumbaugh <drumbaugh@psu.edu> 
  *
@@ -14,12 +14,7 @@
 
 template <typename S>
 concept ShardInterface = requires(S s, void *p) {
-    //s.point_lookup();
-    //s.tombstone_lookup();
-    //s.delete_record();
-
-    {s.get_query_state(p)} -> std::convertible_to<void*>;
-    {s.delete_query_state(p)};
+    s.point_lookup();
 
     {s.get_record_count()} -> std::convertible_to<size_t>;
     {s.get_tombstone_count()} -> std::convertible_to<size_t>;
diff --git a/include/shard/MemISAM.h b/include/shard/MemISAM.h
index d1f3bb3..55699be 100644
--- a/include/shard/MemISAM.h
+++ b/include/shard/MemISAM.h
@@ -15,6 +15,7 @@
 #include <memory>
 
 #include "framework/MutableBuffer.h"
+#include "util/bf_config.h"
 #include "ds/PriorityQueue.h"
 #include "util/Cursor.h"
 #include "util/timer.h"
@@ -43,37 +44,11 @@ constexpr static size_t inmem_isam_node_keyskip = sizeof(K) * inmem_isam_fanout;
 static_assert(sizeof(InMemISAMNode) == inmem_isam_node_size, "node size does not match");
 
 public:
-    MemISAM(std::string data_fname, size_t record_cnt, size_t tombstone_cnt, BloomFilter *bf)
-    : m_reccnt(record_cnt), m_tombstone_cnt(tombstone_cnt), m_deleted_cnt(0) {
-
-        // read the stored data file the file
-        size_t alloc_size = (record_cnt * sizeof(R)) + (CACHELINE_SIZE - (record_cnt * sizeof(R)) % CACHELINE_SIZE);
-        assert(alloc_size % CACHELINE_SIZE == 0);
-        m_data = (R*) std::aligned_alloc(CACHELINE_SIZE, alloc_size);
-
-        FILE *file = fopen(data_fname.c_str(), "rb");
-        assert(file);
-        auto res = fread(m_data, sizeof(R), m_reccnt, file);
-        assert (res == m_reccnt);
-        fclose(file);
-
-        // We can't really persist the internal structure, as it uses
-        // pointers, which are invalidated by the move. So we'll just
-        // rebuild it.
-        this->build_internal_levels();
-
-        // rebuild the bloom filter
-        for (size_t i=0; i<m_reccnt; i++) {
-            auto rec = this->get_record_at(i);
-            if (rec->is_tombstone()) {
-                bf->insert(rec->key);
-            }
-        }
-    }
-
-    MemISAM(MutableBuffer<R>* buffer, BloomFilter* bf)
+    MemISAM(MutableBuffer<R>* buffer)
     :m_reccnt(0), m_tombstone_cnt(0), m_isam_nodes(nullptr), m_deleted_cnt(0) {
 
+        m_bf = new BloomFilter<K>(BF_FPR, buffer->get_tombstone_count(), BF_HASH_FUNCS);
+
         size_t alloc_size = (buffer->get_record_count() * sizeof(R)) + (CACHELINE_SIZE - (buffer->get_record_count() * sizeof(R)) % CACHELINE_SIZE);
         assert(alloc_size % CACHELINE_SIZE == 0);
         m_data = (R*)std::aligned_alloc(CACHELINE_SIZE, alloc_size);
@@ -104,9 +79,9 @@ public:
             //Masking off the ts.
             base->header &= 1;
             m_data[m_reccnt++] = *base;
-            if (bf && base->is_tombstone()) {
+            if (m_bf && base->is_tombstone()) {
                 ++m_tombstone_cnt;
-                bf->insert(base->key);
+                m_bf->insert(base->key);
             }
 
             base++;
@@ -124,26 +99,30 @@ public:
         //fprintf(stdout, "%ld %ld %ld\n", sort_time, copy_time, level_time);
     }
 
-    MemISAM(MemISAM** runs, size_t len, BloomFilter* bf)
-    :m_reccnt(0), m_tombstone_cnt(0), m_deleted_cnt(0), m_isam_nodes(nullptr) {
+    MemISAM(MemISAM** runs, size_t len)
+    : m_reccnt(0), m_tombstone_cnt(0), m_deleted_cnt(0), m_isam_nodes(nullptr) {
         std::vector<Cursor<R>> cursors;
         cursors.reserve(len);
 
         PriorityQueue<R> pq(len);
 
         size_t attemp_reccnt = 0;
+        size_t tombstone_count = 0;
         
         for (size_t i = 0; i < len; ++i) {
             if (runs[i]) {
                 auto base = runs[i]->sorted_output();
                 cursors.emplace_back(Cursor{base, base + runs[i]->get_record_count(), 0, runs[i]->get_record_count()});
                 attemp_reccnt += runs[i]->get_record_count();
+                tombstone_count += runs[i]->get_tombstone_count();
                 pq.push(cursors[i].ptr, i);
             } else {
                 cursors.emplace_back(Cursor<R>{nullptr, nullptr, 0, 0});
             }
         }
 
+        m_bf = new BloomFilter<K>(BF_FPR, tombstone_count, BF_HASH_FUNCS);
+
         size_t alloc_size = (attemp_reccnt * sizeof(R)) + (CACHELINE_SIZE - (attemp_reccnt * sizeof(R)) % CACHELINE_SIZE);
         assert(alloc_size % CACHELINE_SIZE == 0);
         m_data = (R*)std::aligned_alloc(CACHELINE_SIZE, alloc_size);
@@ -167,7 +146,7 @@ public:
                     m_data[m_reccnt++] = *cursor.ptr;
                     if (cursor.ptr->is_tombstone()) {
                         ++m_tombstone_cnt;
-                        bf->insert(cursor.ptr->key);
+                        m_bf->insert(cursor.ptr->key);
                     }
                 }
                 pq.pop();
@@ -184,6 +163,7 @@ public:
     ~MemISAM() {
         if (m_data) free(m_data);
         if (m_isam_nodes) free(m_isam_nodes);
+        if (m_bf) delete m_bf;
     }
 
     R* sorted_output() const {
@@ -259,7 +239,11 @@ public:
         return pos - m_data;
     }
 
-    bool check_tombstone(const K& key, const V& val) const {
+    bool check_tombstone(const R& rec) const{
+        if (!m_bf->lookup(rec.key)) {
+            return false;
+        }
+
         size_t idx = get_lower_bound(key);
         if (idx >= m_reccnt) {
             return false;
@@ -271,17 +255,10 @@ public:
         return *ptr == R {key, val} && ptr->is_tombstone();
     }
 
-    size_t get_memory_utilization() {
+    size_t get_memory_usage() {
         return m_reccnt * sizeof(R) + m_internal_node_cnt * inmem_isam_node_size;
     }
 
-    void persist_to_file(std::string data_fname) {
-        FILE *file = fopen(data_fname.c_str(), "wb");
-        assert(file);
-        fwrite(m_data, sizeof(R), m_reccnt, file);
-        fclose(file);
-    }
-    
 private:
     void build_internal_levels() {
         size_t n_leaf_nodes = m_reccnt / inmem_isam_leaf_fanout + (m_reccnt % inmem_isam_leaf_fanout != 0);
@@ -349,6 +326,7 @@ private:
 
     // Members: sorted data, internal ISAM levels, reccnt;
     R* m_data;
+    BloomFilter<K> *m_bf;
     InMemISAMNode* m_isam_nodes;
     InMemISAMNode* m_root;
     size_t m_reccnt;
diff --git a/include/shard/WIRS.h b/include/shard/WIRS.h
index 9f37396..42dbcfd 100644
--- a/include/shard/WIRS.h
+++ b/include/shard/WIRS.h
@@ -18,6 +18,7 @@
 #include "util/Cursor.h"
 #include "ds/Alias.h"
 #include "ds/BloomFilter.h"
+#include "util/bf_config.h"
 #include "util/Record.h"
 #include "framework/MutableBuffer.h"
 
@@ -25,6 +26,11 @@ namespace de {
 
 thread_local size_t wirs_cancelations = 0;
 
+template <WeightedRecordInterface R>
+struct wirs_query_parms {
+    decltype(R::key) lower_bound;
+    decltype(R::key) upper_bound;
+};
 
 template <WeightedRecordInterface R>
 class WIRS {
@@ -54,12 +60,8 @@ private:
     };
 
 public:
-    struct wirs_query_parms {
-        K lower_bound;
-        K upper_bound;
-    };
 
-    WIRS(MutableBuffer<R>* buffer, BloomFilter* bf)
+    WIRS(MutableBuffer<R>* buffer)
     : m_reccnt(0), m_tombstone_cnt(0), m_deleted_cnt(0), m_total_weight(0), m_rejection_cnt(0), 
       m_ts_check_cnt(0), m_root(nullptr) {
 
@@ -67,6 +69,8 @@ public:
         assert(alloc_size % CACHELINE_SIZE == 0);
         m_data = (R*)std::aligned_alloc(CACHELINE_SIZE, alloc_size);
 
+        m_bf = new BloomFilter<K>(BF_FPR, buffer->get_tombstone_count(), BF_HASH_FUNCS);
+
         size_t offset = 0;
         m_reccnt = 0;
         auto base = buffer->sorted_output();
@@ -88,9 +92,9 @@ public:
             m_data[m_reccnt++] = *base;
             m_total_weight+= base->weight;
 
-            if (bf && base->is_tombstone()) {
+            if (m_bf && base->is_tombstone()) {
                 m_tombstone_cnt++;
-                bf->insert(base->key);
+                m_bf->insert(base->key);
             }
             
             base++;
@@ -101,7 +105,7 @@ public:
         }
     }
 
-    WIRS(WIRS** shards, size_t len, BloomFilter* bf)
+    WIRS(WIRS** shards, size_t len)
     : m_reccnt(0), m_tombstone_cnt(0), m_deleted_cnt(0), m_total_weight(0), m_rejection_cnt(0), m_ts_check_cnt(0), 
       m_root(nullptr) {
         std::vector<Cursor<R>> cursors;
@@ -110,18 +114,22 @@ public:
         PriorityQueue<R> pq(len);
 
         size_t attemp_reccnt = 0;
+        size_t tombstone_count = 0;
         
         for (size_t i = 0; i < len; ++i) {
             if (shards[i]) {
                 auto base = shards[i]->sorted_output();
                 cursors.emplace_back(Cursor{base, base + shards[i]->get_record_count(), 0, shards[i]->get_record_count()});
                 attemp_reccnt += shards[i]->get_record_count();
+                tombstone_count += shards[i]->get_tombstone_count();
                 pq.push(cursors[i].ptr, i);
             } else {
                 cursors.emplace_back(Cursor<R>{nullptr, nullptr, 0, 0});
             }
         }
 
+        m_bf = new BloomFilter<K>(BF_FPR, tombstone_count, BF_HASH_FUNCS);
+
         size_t alloc_size = (attemp_reccnt * sizeof(R)) + (CACHELINE_SIZE - (attemp_reccnt * sizeof(R)) % CACHELINE_SIZE);
         assert(alloc_size % CACHELINE_SIZE == 0);
         m_data = (R*)std::aligned_alloc(CACHELINE_SIZE, alloc_size);
@@ -142,9 +150,9 @@ public:
                 if (!cursor.ptr->is_deleted()) {
                     m_data[m_reccnt++] = *cursor.ptr;
                     m_total_weight += cursor.ptr->weight;
-                    if (bf && cursor.ptr->is_tombstone()) {
+                    if (m_bf && cursor.ptr->is_tombstone()) {
                         ++m_tombstone_cnt;
-                        if (bf) bf->insert(cursor.ptr->key);
+                        if (m_bf) m_bf->insert(cursor.ptr->key);
                     }
                 }
                 pq.pop();
@@ -164,6 +172,8 @@ public:
             if (m_alias[i]) delete m_alias[i];
         }
 
+        if (m_bf) delete m_bf;
+
         free_tree(m_root);
     }
 
@@ -202,12 +212,13 @@ public:
         return m_data + idx;
     }
 
+   /*
     // low - high -> decompose to a set of nodes.
     // Build Alias across the decomposed nodes.
     WIRSState<R>* get_query_state(void *query_parameters) {
         auto res = new WIRSState();
-        K lower_key = ((wirs_query_parms *) query_parameters)->lower_bound;
-        K upper_key = ((wirs_query_parms *) query_parameters)->upper_bound;
+        K lower_key = ((wirs_query_parms<R> *) query_parameters)->lower_bound;
+        K upper_key = ((wirs_query_parms<R> *) query_parameters)->upper_bound;
 
         // Simulate a stack to unfold recursion.        
         double tot_weight = 0.0;
@@ -240,40 +251,7 @@ public:
         WIRSState<R> *s = (WIRSState<R> *) state;
         delete s;
     }
-
-    // returns the number of records sampled
-    // NOTE: This operation returns records strictly between the lower and upper bounds, not
-    // including them.
-    size_t get_samples(void* shard_state, std::vector<R> &result_set, const K& lower_key, const K& upper_key, size_t sample_sz, gsl_rng *rng) {
-        WIRSState<R> *state = (WIRSState<R> *) shard_state;
-        if (sample_sz == 0) {
-            return 0;
-        }
-
-        // k -> sampling: three levels. 1. select a node -> select a fat point -> select a record.
-        size_t cnt = 0;
-        size_t attempts = 0;
-        do {
-            ++attempts;
-            // first level....
-            auto node = state->nodes[state->top_level_alias->get(rng)];
-            // second level...
-            auto fat_point = node->low + node->alias->get(rng);
-            // third level...
-            size_t rec_offset = fat_point * m_group_size + m_alias[fat_point]->get(rng);
-            auto record = m_data + rec_offset;
-
-            // bounds rejection
-            if (lower_key > record->key || upper_key < record->key) {
-                continue;
-            } 
-
-            result_set.emplace_back(*record);
-            cnt++;
-        } while (attempts < sample_sz);
-
-        return cnt;
-    }
+    */
 
     size_t get_lower_bound(const K& key) const {
         size_t min = 0;
@@ -294,6 +272,10 @@ public:
     }
 
     bool check_tombstone(const R& rec) {
+        if(!m_bf.lookup(rec.key)) {
+            return false;
+        }
+
         m_ts_check_cnt++;
         size_t idx = get_lower_bound(rec.key);
         if (idx >= m_reccnt) {
@@ -414,6 +396,7 @@ private:
     size_t m_group_size;
     size_t m_ts_check_cnt;
     size_t m_deleted_cnt;
+    BloomFilter<K> m_bf;
 
     // The number of rejections caused by tombstones
     // in this WIRS.
diff --git a/include/util/Record.h b/include/util/Record.h
index ce101f4..fc543ed 100644
--- a/include/util/Record.h
+++ b/include/util/Record.h
@@ -20,27 +20,15 @@ template<typename R>
 concept RecordInterface = requires(R r, R s) {
     r.key;
     r.value;
-    r.header;
 
-    {r.is_tombstone()} -> std::convertible_to<bool>;
-    {r.is_deleted()} -> std::convertible_to<bool>;
-    r.set_delete();
-    r.set_tombstone(std::declval<bool>);
     { r < s } ->std::convertible_to<bool>;
     { r == s } ->std::convertible_to<bool>;
-    { r.header < s.header } -> std::convertible_to<bool>;
 };
 
-template <typename R>
-concept WeightedRecordInterface = RecordInterface<R> && requires(R r) {
-    {r.weight} -> std::convertible_to<double>;
-};
-
-template <typename K, typename V>
-struct Record {
-    K key;
-    V value;
-    uint32_t header = 0;
+template<RecordInterface R>
+struct WrappedRecord {
+    R rec;
+    uint32_t header;
 
     inline void set_delete() {
         header |= 2;
@@ -61,8 +49,20 @@ struct Record {
     inline bool is_tombstone() const {
         return header & 1;
     }
+};
+
+template <typename R>
+concept WeightedRecordInterface = RecordInterface<R> && requires(R r) {
+    {r.weight} -> std::convertible_to<double>;
+};
+
+template <typename K, typename V>
+struct Record {
+    K key;
+    V value;
+    uint32_t header = 0;
 
-    inline bool operator<(const Record& other) const {
+       inline bool operator<(const Record& other) const {
         return key < other.key || (key == other.key && value < other.value);
     }
 
-- 
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