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-rw-r--r--include/shard/AugBTree.h371
1 files changed, 371 insertions, 0 deletions
diff --git a/include/shard/AugBTree.h b/include/shard/AugBTree.h
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+/*
+ * include/shard/AugBTree.h
+ *
+ * Copyright (C) 2023 Dong Xie <dongx@psu.edu>
+ * 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 "framework/ShardRequirements.h"
+
+#include "psu-ds/PriorityQueue.h"
+#include "util/Cursor.h"
+#include "psu-ds/Alias.h"
+#include "psu-ds/BloomFilter.h"
+#include "util/bf_config.h"
+
+using psudb::CACHELINE_SIZE;
+using psudb::BloomFilter;
+using psudb::PriorityQueue;
+using psudb::queue_record;
+using psudb::Alias;
+
+namespace de {
+
+thread_local size_t wirs_cancelations = 0;
+
+template <WeightedRecordInterface R>
+struct AugBTreeNode {
+ struct AugBTreeNode<R> *left, *right;
+ decltype(R::key) low, high;
+ decltype(R::weight) weight;
+ Alias* alias;
+};
+
+template <WeightedRecordInterface R>
+class AugBTree {
+private:
+ typedef decltype(R::key) K;
+ typedef decltype(R::value) V;
+ typedef decltype(R::weight) W;
+
+public:
+ AugBTree(MutableBuffer<R>* buffer)
+ : m_reccnt(0), m_tombstone_cnt(0), m_total_weight(0), m_root(nullptr) {
+ 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);
+
+ 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>>());
+
+ while (base < stop) {
+ if (!(base->is_tombstone()) && (base + 1) < stop) {
+ if (base->rec == (base + 1)->rec && (base + 1)->is_tombstone()) {
+ base += 2;
+ wirs_cancelations++;
+ 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;
+ m_total_weight+= base->rec.weight;
+
+ if (m_bf && base->is_tombstone()) {
+ m_tombstone_cnt++;
+ m_bf->insert(base->rec);
+ }
+
+ base++;
+ }
+
+ if (m_reccnt > 0) {
+ build_wirs_structure();
+ }
+ }
+
+ AugBTree(AugBTree** shards, size_t len)
+ : m_reccnt(0), m_tombstone_cnt(0), m_total_weight(0), m_root(nullptr) {
+ 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);
+
+ 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_cursor<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;
+ m_total_weight += cursor.ptr->rec.weight;
+ 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) {
+ build_wirs_structure();
+ }
+ }
+
+ ~AugBTree() {
+ if (m_data) free(m_data);
+ for (size_t i=0; i<m_alias.size(); i++) {
+ if (m_alias[i]) delete m_alias[i];
+ }
+
+ if (m_bf) delete m_bf;
+
+ free_tree(m_root);
+ }
+
+ 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_alloc_size + m_node_cnt * sizeof(AugBTreeNode<Wrapped<R>>);
+ }
+
+ size_t get_aux_memory_usage() {
+ return 0;
+ }
+
+ size_t get_lower_bound(const K& key) const {
+ size_t min = 0;
+ size_t max = m_reccnt - 1;
+
+ const char * record_key;
+ while (min < max) {
+ size_t mid = (min + max) / 2;
+
+ if (key > m_data[mid].rec.key) {
+ min = mid + 1;
+ } else {
+ max = mid;
+ }
+ }
+
+ return min;
+ }
+
+ W find_covering_nodes(K lower_key, K upper_key, std::vector<void *> &nodes, std::vector<W> &weights) {
+ W total_weight = 0;
+
+ /* Simulate a stack to unfold recursion. */
+ struct AugBTreeNode<R>* st[64] = {0};
+ st[0] = m_root;
+ size_t top = 1;
+ while(top > 0) {
+ auto now = st[--top];
+ if (covered_by(now, lower_key, upper_key) ||
+ (now->left == nullptr && now->right == nullptr && intersects(now, lower_key, upper_key))) {
+ nodes.emplace_back(now);
+ weights.emplace_back(now->weight);
+ total_weight += now->weight;
+ } else {
+ if (now->left && intersects(now->left, lower_key, upper_key)) st[top++] = now->left;
+ if (now->right && intersects(now->right, lower_key, upper_key)) st[top++] = now->right;
+ }
+ }
+
+
+ return total_weight;
+ }
+
+ Wrapped<R> *get_weighted_sample(K lower_key, K upper_key, void *internal_node, gsl_rng *rng) {
+ /* k -> sampling: three levels. 1. select a node -> select a fat point -> select a record. */
+
+ /* first level */
+ auto node = (AugBTreeNode<R>*) internal_node;
+
+ /* 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->rec.key || upper_key < record->rec.key) {
+ return nullptr;
+ }
+
+ return record;
+ }
+
+private:
+
+ bool covered_by(struct AugBTreeNode<R>* node, const K& lower_key, const K& upper_key) {
+ auto low_index = node->low * m_group_size;
+ auto high_index = std::min((node->high + 1) * m_group_size - 1, m_reccnt - 1);
+ return lower_key < m_data[low_index].rec.key && m_data[high_index].rec.key < upper_key;
+ }
+
+ bool intersects(struct AugBTreeNode<R>* node, const K& lower_key, const K& upper_key) {
+ auto low_index = node->low * m_group_size;
+ auto high_index = std::min((node->high + 1) * m_group_size - 1, m_reccnt - 1);
+ return lower_key < m_data[high_index].rec.key && m_data[low_index].rec.key < upper_key;
+ }
+
+ void build_wirs_structure() {
+ m_group_size = std::ceil(std::log(m_reccnt));
+ size_t n_groups = std::ceil((double) m_reccnt / (double) m_group_size);
+
+ // Fat point construction + low level alias....
+ double sum_weight = 0.0;
+ std::vector<W> weights;
+ std::vector<double> group_norm_weight;
+ size_t i = 0;
+ size_t group_no = 0;
+ while (i < m_reccnt) {
+ double group_weight = 0.0;
+ group_norm_weight.clear();
+ for (size_t k = 0; k < m_group_size && i < m_reccnt; ++k, ++i) {
+ auto w = m_data[i].rec.weight;
+ group_norm_weight.emplace_back(w);
+ group_weight += w;
+ sum_weight += w;
+ }
+
+ for (auto& w: group_norm_weight)
+ if (group_weight) w /= group_weight;
+ else w = 1.0 / group_norm_weight.size();
+ m_alias.emplace_back(new Alias(group_norm_weight));
+
+
+ weights.emplace_back(group_weight);
+ }
+
+ assert(weights.size() == n_groups);
+
+ m_root = construct_AugBTreeNode(weights, 0, n_groups-1);
+ }
+
+ struct AugBTreeNode<R>* construct_AugBTreeNode(const std::vector<W>& weights, size_t low, size_t high) {
+ if (low == high) {
+ return new AugBTreeNode<R>{nullptr, nullptr, low, high, weights[low], new Alias({1.0})};
+ } else if (low > high) return nullptr;
+
+ std::vector<double> node_weights;
+ W sum = 0;
+ for (size_t i = low; i < high; ++i) {
+ node_weights.emplace_back(weights[i]);
+ sum += weights[i];
+ }
+
+ for (auto& w: node_weights)
+ if (sum) w /= sum;
+ else w = 1.0 / node_weights.size();
+
+ m_node_cnt += 1;
+ size_t mid = (low + high) / 2;
+ return new AugBTreeNode<R>{construct_AugBTreeNode(weights, low, mid),
+ construct_AugBTreeNode(weights, mid + 1, high),
+ low, high, sum, new Alias(node_weights)};
+ }
+
+ void free_tree(struct AugBTreeNode<R>* node) {
+ if (node) {
+ delete node->alias;
+ free_tree(node->left);
+ free_tree(node->right);
+ delete node;
+ }
+ }
+
+ Wrapped<R>* m_data;
+ std::vector<Alias *> m_alias;
+ AugBTreeNode<R>* m_root;
+ W m_total_weight;
+ size_t m_reccnt;
+ size_t m_tombstone_cnt;
+ size_t m_group_size;
+ size_t m_alloc_size;
+ size_t m_node_cnt;
+ BloomFilter<R> *m_bf;
+};
+}