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be7c937 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 | #include "wayy_db/ops/joins.hpp"
#include <algorithm>
#include <cstring>
#include <unordered_map>
#include <vector>
namespace wayy_db::ops {
namespace {
// Hash combine for multi-key joins
struct KeyHash {
size_t operator()(const std::vector<int64_t>& key) const {
size_t hash = 0;
for (auto val : key) {
hash ^= std::hash<int64_t>{}(val) + 0x9e3779b9 + (hash << 6) + (hash >> 2);
}
return hash;
}
};
// Extract join key values from a row
std::vector<int64_t> extract_key(const Table& table,
const std::vector<std::string>& on,
size_t row) {
std::vector<int64_t> key;
key.reserve(on.size());
for (const auto& col_name : on) {
const Column& col = table.column(col_name);
switch (col.dtype()) {
case DType::Int64:
case DType::Timestamp:
key.push_back(const_cast<Column&>(col).as_int64()[row]);
break;
case DType::Symbol:
key.push_back(const_cast<Column&>(col).as_symbol()[row]);
break;
default:
throw InvalidOperation("Join key column must be Int64, Timestamp, or Symbol");
}
}
return key;
}
// Group row indices by key values
std::unordered_map<std::vector<int64_t>, std::vector<size_t>, KeyHash>
group_by_key(const Table& table, const std::vector<std::string>& on) {
std::unordered_map<std::vector<int64_t>, std::vector<size_t>, KeyHash> groups;
for (size_t i = 0; i < table.num_rows(); ++i) {
auto key = extract_key(table, on, i);
groups[key].push_back(i);
}
return groups;
}
} // namespace
Table aj(const Table& left, const Table& right,
const std::vector<std::string>& on,
const std::string& as_of) {
// Validate inputs
if (!left.is_sorted() || left.sorted_by() != as_of) {
throw InvalidOperation("Left table must be sorted by " + as_of);
}
if (!right.is_sorted() || right.sorted_by() != as_of) {
throw InvalidOperation("Right table must be sorted by " + as_of);
}
// Group right table by join keys
auto right_groups = group_by_key(right, on);
// Get timestamp columns
auto left_ts = const_cast<Table&>(left).column(as_of).as_int64();
auto right_ts = const_cast<Table&>(right).column(as_of).as_int64();
// Result builders - collect matching indices
std::vector<size_t> left_indices;
std::vector<size_t> right_indices; // -1 means no match
left_indices.reserve(left.num_rows());
right_indices.reserve(left.num_rows());
// For each left row, find the most recent right row
for (size_t i = 0; i < left.num_rows(); ++i) {
auto key = extract_key(left, on, i);
int64_t ts = left_ts[i];
auto group_it = right_groups.find(key);
if (group_it == right_groups.end()) {
// No matching key in right table
left_indices.push_back(i);
right_indices.push_back(static_cast<size_t>(-1));
continue;
}
const auto& group = group_it->second;
// Binary search for largest timestamp <= ts
auto it = std::upper_bound(group.begin(), group.end(), ts,
[&right_ts](int64_t t, size_t idx) { return t < right_ts[idx]; });
if (it != group.begin()) {
--it;
left_indices.push_back(i);
right_indices.push_back(*it);
} else {
// No timestamp <= ts
left_indices.push_back(i);
right_indices.push_back(static_cast<size_t>(-1));
}
}
// Build result table
Table result("aj_result");
// Add left columns
for (const auto& col_name : left.column_names()) {
const Column& src = left.column(col_name);
size_t elem_size = dtype_size(src.dtype());
std::vector<uint8_t> data(left_indices.size() * elem_size);
const uint8_t* src_data = static_cast<const uint8_t*>(src.data());
for (size_t i = 0; i < left_indices.size(); ++i) {
std::memcpy(data.data() + i * elem_size,
src_data + left_indices[i] * elem_size,
elem_size);
}
result.add_column(Column(col_name, src.dtype(), std::move(data)));
}
// Add right columns (excluding join keys and as_of)
for (const auto& col_name : right.column_names()) {
// Skip if already in left or is a join key
if (result.has_column(col_name)) continue;
if (std::find(on.begin(), on.end(), col_name) != on.end()) continue;
const Column& src = right.column(col_name);
size_t elem_size = dtype_size(src.dtype());
std::vector<uint8_t> data(right_indices.size() * elem_size, 0);
const uint8_t* src_data = static_cast<const uint8_t*>(src.data());
for (size_t i = 0; i < right_indices.size(); ++i) {
if (right_indices[i] != static_cast<size_t>(-1)) {
std::memcpy(data.data() + i * elem_size,
src_data + right_indices[i] * elem_size,
elem_size);
}
// else: leave as zero (null representation)
}
result.add_column(Column(col_name, src.dtype(), std::move(data)));
}
result.set_sorted_by(as_of);
return result;
}
Table wj(const Table& left, const Table& right,
const std::vector<std::string>& on,
const std::string& as_of,
int64_t window_before,
int64_t window_after) {
// Validate inputs
if (!left.is_sorted() || left.sorted_by() != as_of) {
throw InvalidOperation("Left table must be sorted by " + as_of);
}
if (!right.is_sorted() || right.sorted_by() != as_of) {
throw InvalidOperation("Right table must be sorted by " + as_of);
}
// Group right table by join keys
auto right_groups = group_by_key(right, on);
// Get timestamp columns
auto left_ts = const_cast<Table&>(left).column(as_of).as_int64();
auto right_ts = const_cast<Table&>(right).column(as_of).as_int64();
// Result builders
std::vector<size_t> left_indices;
std::vector<size_t> right_indices;
// For each left row, find all right rows in window
for (size_t i = 0; i < left.num_rows(); ++i) {
auto key = extract_key(left, on, i);
int64_t ts = left_ts[i];
int64_t ts_min = ts - window_before;
int64_t ts_max = ts + window_after;
auto group_it = right_groups.find(key);
if (group_it == right_groups.end()) {
continue; // No matching key
}
const auto& group = group_it->second;
// Find range [ts_min, ts_max]
auto lower = std::lower_bound(group.begin(), group.end(), ts_min,
[&right_ts](size_t idx, int64_t t) { return right_ts[idx] < t; });
auto upper = std::upper_bound(group.begin(), group.end(), ts_max,
[&right_ts](int64_t t, size_t idx) { return t < right_ts[idx]; });
for (auto it = lower; it != upper; ++it) {
left_indices.push_back(i);
right_indices.push_back(*it);
}
}
// Build result table (similar to aj)
Table result("wj_result");
// Add left columns
for (const auto& col_name : left.column_names()) {
const Column& src = left.column(col_name);
size_t elem_size = dtype_size(src.dtype());
std::vector<uint8_t> data(left_indices.size() * elem_size);
const uint8_t* src_data = static_cast<const uint8_t*>(src.data());
for (size_t i = 0; i < left_indices.size(); ++i) {
std::memcpy(data.data() + i * elem_size,
src_data + left_indices[i] * elem_size,
elem_size);
}
result.add_column(Column(col_name, src.dtype(), std::move(data)));
}
// Add right columns (excluding join keys)
for (const auto& col_name : right.column_names()) {
if (result.has_column(col_name)) continue;
if (std::find(on.begin(), on.end(), col_name) != on.end()) continue;
const Column& src = right.column(col_name);
size_t elem_size = dtype_size(src.dtype());
std::vector<uint8_t> data(right_indices.size() * elem_size);
const uint8_t* src_data = static_cast<const uint8_t*>(src.data());
for (size_t i = 0; i < right_indices.size(); ++i) {
std::memcpy(data.data() + i * elem_size,
src_data + right_indices[i] * elem_size,
elem_size);
}
result.add_column(Column(col_name, src.dtype(), std::move(data)));
}
if (!result.column_names().empty()) {
result.set_sorted_by(as_of);
}
return result;
}
Table inner_join(const Table& left, const Table& right,
const std::vector<std::string>& on) {
// TODO: Implement inner join
throw InvalidOperation("inner_join not yet implemented");
}
Table left_join(const Table& left, const Table& right,
const std::vector<std::string>& on) {
// TODO: Implement left join
throw InvalidOperation("left_join not yet implemented");
}
} // namespace wayy_db::ops
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