From f462921cbc52688fb478c6ac86a891e596fd6053 Mon Sep 17 00:00:00 2001
From: Douglas Rumbaugh <dbr4@psu.edu>
Date: Wed, 26 Jul 2023 13:51:06 -0400
Subject: Alex shard progress

---
 include/shard/Alex.h | 354 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 354 insertions(+)
 create mode 100644 include/shard/Alex.h

(limited to 'include/shard')

diff --git a/include/shard/Alex.h b/include/shard/Alex.h
new file mode 100644
index 0000000..9ba9666
--- /dev/null
+++ b/include/shard/Alex.h
@@ -0,0 +1,354 @@
+/*
+ * include/shard/Alex.h
+ *
+ * Copyright (C) 2023 Douglas B. Rumbaugh <drumbaugh@psu.edu>
+ *
+ * All rights reserved. Published under the Modified BSD License.
+ *
+ */
+#pragma once
+
+
+#include <vector>
+#include <cassert>
+#include <queue>
+#include <memory>
+#include <concepts>
+
+#include "alex.h"
+#include "ds/PriorityQueue.h"
+#include "util/Cursor.h"
+#include "ds/BloomFilter.h"
+#include "util/bf_config.h"
+#include "framework/MutableBuffer.h"
+#include "framework/RecordInterface.h"
+#include "framework/ShardInterface.h"
+#include "framework/QueryInterface.h"
+
+namespace de {
+
+template <RecordInterface R>
+struct alex_range_query_parms {
+    decltype(R::key) lower_bound;
+    decltype(R::key) upper_bound;
+};
+
+template <RecordInterface R>
+class AlexRangeQuery;
+
+template <RecordInterface R>
+struct AlexState {
+    size_t start_idx;
+    size_t stop_idx;
+};
+
+template <RecordInterface R>
+struct AlexBufferState {
+    size_t cutoff;
+    Alias* alias;
+
+    ~AlexBufferState() {
+        delete alias;
+    }
+};
+
+
+template <RecordInterface R, size_t epsilon=128>
+class Alex {
+private:
+    typedef decltype(R::key) K;
+    typedef decltype(R::value) V;
+
+public:
+
+    // FIXME: there has to be a better way to do this
+    friend class AlexRangeQuery<R>;
+
+    Alex(MutableBuffer<R>* buffer)
+    : m_reccnt(0), m_tombstone_cnt(0) {
+
+        m_alloc_size = (buffer->get_record_count() * sizeof(Wrapped<R>)) + (CACHELINE_SIZE - (buffer->get_record_count() * sizeof(Wrapped<R>)) % CACHELINE_SIZE);
+        assert(m_alloc_size % CACHELINE_SIZE == 0);
+        m_data = (Wrapped<R>*)std::aligned_alloc(CACHELINE_SIZE, m_alloc_size);
+        std::vector<std::pair<K, V>> temp_records;
+
+        m_bf = new BloomFilter<R>(BF_FPR, buffer->get_tombstone_count(), BF_HASH_FUNCS);
+
+        size_t offset = 0;
+        m_reccnt = 0;
+        auto base = buffer->get_data();
+        auto stop = base + buffer->get_record_count();
+
+        std::sort(base, stop, std::less<Wrapped<R>>());
+
+        K min_key = base->rec.key;
+        K max_key = (stop - 1)->rec.key;
+
+        while (base < stop) {
+            if (!(base->is_tombstone()) && (base + 1) < stop) {
+                if (base->rec == (base + 1)->rec && (base + 1)->is_tombstone()) {
+                    base += 2;
+                    continue;
+                }
+            } else if (base->is_deleted()) {
+                base += 1;
+                continue;
+            }
+
+            // FIXME: this shouldn't be necessary, but the tagged record
+            // bypass doesn't seem to be working on this code-path, so this
+            // ensures that tagged records from the buffer are able to be
+            // dropped, eventually. It should only need to be &= 1
+            base->header &= 3;
+            m_data[m_reccnt++] = *base;
+            temp_records.push_back({base->rec.key, base->rec.value});
+
+            if (m_bf && base->is_tombstone()) {
+                m_tombstone_cnt++;
+                m_bf->insert(base->rec);
+            }
+            
+            base++;
+        }
+
+        if (m_reccnt > 0) {
+            m_alex = alex::Alex<K, V>();
+            m_alex.set_expected_insert_frac(0);
+            m_alex.bulkload(temp_records.data(), temp_records.size());
+        }
+    }
+
+    Alex(Alex** shards, size_t len)
+    : m_reccnt(0), m_tombstone_cnt(0) {
+        std::vector<Cursor<Wrapped<R>>> cursors;
+        cursors.reserve(len);
+
+        PriorityQueue<Wrapped<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]->get_data();
+                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<Wrapped<R>>{nullptr, nullptr, 0, 0});
+            }
+        }
+
+        m_bf = new BloomFilter<R>(BF_FPR, tombstone_count, BF_HASH_FUNCS);
+
+        m_alloc_size = (attemp_reccnt * sizeof(Wrapped<R>)) + (CACHELINE_SIZE - (attemp_reccnt * sizeof(Wrapped<R>)) % CACHELINE_SIZE);
+        assert(m_alloc_size % CACHELINE_SIZE == 0);
+        m_data = (Wrapped<R>*)std::aligned_alloc(CACHELINE_SIZE, m_alloc_size);
+
+        std::vector<std::pair<K, V>> temp_records;
+
+        while (pq.size()) {
+            auto now = pq.peek();
+            auto next = pq.size() > 1 ? pq.peek(1) : queue_record<Wrapped<R>>{nullptr, 0};
+            if (!now.data->is_tombstone() && next.data != nullptr &&
+                now.data->rec == next.data->rec && next.data->is_tombstone()) {
+                
+                pq.pop(); pq.pop();
+                auto& cursor1 = cursors[now.version];
+                auto& cursor2 = cursors[next.version];
+                if (advance_cur5sor<Wrapped<R>>(cursor1)) pq.push(cursor1.ptr, now.version);
+                if (advance_cursor<Wrapped<R>>(cursor2)) pq.push(cursor2.ptr, next.version);
+            } else {
+                auto& cursor = cursors[now.version];
+                if (!cursor.ptr->is_deleted()) {
+                    m_data[m_reccnt++] = *cursor.ptr;
+                    temp_records.pushback({cursor.ptr->rec.key, cursor.ptr->rec.value});
+                    if (m_bf && cursor.ptr->is_tombstone()) {
+                        ++m_tombstone_cnt;
+                        if (m_bf) m_bf->insert(cursor.ptr->rec);
+                    }
+                }
+                pq.pop();
+                
+                if (advance_cursor<Wrapped<R>>(cursor)) pq.push(cursor.ptr, now.version);
+            }
+        }
+
+        if (m_reccnt > 0) {
+            m_alex = alex::Alex<K, V>();
+            m_alex.set_expected_insert_frac(0);
+            m_alex.bulkload(temp_records.data(), temp_records.size());
+        }
+   }
+
+    ~Alex() {
+        if (m_data) free(m_data);
+        if (m_bf) delete m_bf;
+
+    }
+
+    Wrapped<R> *point_lookup(const R &rec, bool filter=false) {
+        if (filter && !m_bf->lookup(rec)) {
+            return nullptr;
+        }
+
+        size_t idx = get_lower_bound(rec.key);
+        if (idx >= m_reccnt) {
+            return nullptr;
+        }
+
+        while (idx < m_reccnt && m_data[idx].rec < rec) ++idx;
+
+        if (m_data[idx].rec == rec) {
+            return m_data + idx;
+        }
+
+        return nullptr;
+    }
+
+    Wrapped<R>* get_data() const {
+        return m_data;
+    }
+    
+    size_t get_record_count() const {
+        return m_reccnt;
+    }
+
+    size_t get_tombstone_count() const {
+        return m_tombstone_cnt;
+    }
+
+    const Wrapped<R>* get_record_at(size_t idx) const {
+        if (idx >= m_reccnt) return nullptr;
+        return m_data + idx;
+    }
+
+
+    size_t get_memory_usage() {
+        return m_alex.size_in_bytes() + m_alloc_size;
+    }
+
+    alex::Alex<K, V>::Iterator get_lower_bound(const K& key) const {
+        auto bound = m_alex.find(key);
+        while (bound != m_alex.end() && bound.key() < key) {
+            bound++;
+        }
+
+        return bound;
+    }
+
+private:
+    Wrapped<R>* m_data;
+    size_t m_reccnt;
+    size_t m_tombstone_cnt;
+    size_t m_alloc_size;
+    K m_max_key;
+    K m_min_key;
+    alex::Alex<K, V> m_alex;
+    BloomFilter<R> *m_bf;
+};
+
+
+template <RecordInterface R>
+class AlexRangeQuery {
+public:
+    static void *get_query_state(Alex<R> *ts, void *parms) {
+        auto res = new AlexState<R>();
+        auto p = (alex_range_query_parms<R> *) parms;
+
+        res->start_idx = ts->get_lower_bound(p->lower_bound);
+        res->stop_idx = ts->get_record_count();
+
+        return res;
+    }
+
+    static void* get_buffer_query_state(MutableBuffer<R> *buffer, void *parms) {
+        auto res = new AlexBufferState<R>();
+        res->cutoff = buffer->get_record_count();
+
+        return res;
+    }
+
+    static void process_query_states(void *query_parms, std::vector<void*> shard_states, void *buff_state) {
+        return;
+    }
+
+    static std::vector<Wrapped<R>> query(Alex<R> *ts, void *q_state, void *parms) {
+        std::vector<Wrapped<R>> records;
+        auto p = (alex_range_query_parms<R> *) parms;
+        auto s = (AlexState<R> *) q_state;
+
+        // if the returned index is one past the end of the
+        // records for the Alex, then there are not records
+        // in the index falling into the specified range.
+        if (s->start_idx == ts->get_record_count()) {
+            return records;
+        }
+
+        auto ptr = ts->get_record_at(s->start_idx);
+        
+        // roll the pointer forward to the first record that is
+        // greater than or equal to the lower bound.
+        while(ptr->rec.key < p->lower_bound) {
+            ptr++;
+        }
+
+        while (ptr->rec.key <= p->upper_bound && ptr < ts->m_data + s->stop_idx) {
+            records.emplace_back(*ptr);
+            ptr++;
+        }
+
+        return records;
+    }
+
+    static std::vector<Wrapped<R>> buffer_query(MutableBuffer<R> *buffer, void *state, void *parms) {
+        auto p = (alex_range_query_parms<R> *) parms;
+        auto s = (AlexBufferState<R> *) state;
+
+        std::vector<Wrapped<R>> records;
+        for (size_t i=0; i<s->cutoff; i++) {
+            auto rec = buffer->get_data() + i;
+            if (rec->rec.key >= p->lower_bound && rec->rec.key <= p->upper_bound) {
+                records.emplace_back(*rec);
+            }
+        }
+
+        return records;
+    }
+
+    static std::vector<R> merge(std::vector<std::vector<R>> &results, void *parms) {
+        size_t total = 0;
+        for (size_t i=0; i<results.size(); i++) {
+            total += results[i].size();
+        }
+
+        if (total == 0) {
+            return std::vector<R>();
+        }
+
+        std::vector<R> output;
+        output.reserve(total);
+
+        for (size_t i=0; i<results.size(); i++) {
+            std::move(results[i].begin(), results[i].end(), std::back_inserter(output));
+        }
+
+        return output;
+    }
+
+    static void delete_query_state(void *state) {
+        auto s = (AlexState<R> *) state;
+        delete s;
+    }
+
+    static void delete_buffer_query_state(void *state) {
+        auto s = (AlexBufferState<R> *) state;
+        delete s;
+    }
+};
+
+;
+
+}
-- 
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