rtpsw commented on code in PR #13880:
URL: https://github.com/apache/arrow/pull/13880#discussion_r954265680
##########
cpp/src/arrow/compute/exec/asof_join_node.cc:
##########
@@ -137,18 +173,88 @@ struct MemoStore {
}
};
+// a specialized higher-performance variation of Hashing64 logic from
hash_join_node
+// the code here avoids recreating objects that are independent of each batch
processed
+class KeyHasher {
+ static constexpr int kMiniBatchLength = util::MiniBatch::kMiniBatchLength;
+
+ public:
+ explicit KeyHasher(const vec_col_index_t& indices)
+ : indices_(indices),
+ metadata_(indices.size()),
+ batch_(NULLPTR),
+ hashes_(),
+ ctx_(),
+ column_arrays_(),
+ stack_() {
+ ctx_.stack = &stack_;
+ column_arrays_.resize(indices.size());
+ }
+
+ Status Init(ExecContext* exec_context, const std::shared_ptr<arrow::Schema>&
schema) {
+ ctx_.hardware_flags = exec_context->cpu_info()->hardware_flags();
+ const auto& fields = schema->fields();
+ for (size_t k = 0; k < metadata_.size(); k++) {
+ ARROW_ASSIGN_OR_RAISE(metadata_[k],
+
ColumnMetadataFromDataType(fields[indices_[k]]->type()));
+ }
+ return stack_.Init(exec_context->memory_pool(),
+ 4 * kMiniBatchLength * sizeof(uint32_t));
+ }
+
+ const std::vector<HashType>& HashesFor(const RecordBatch* batch) {
+ if (batch_ == batch) {
+ return hashes_;
+ }
+ batch_ = NULLPTR; // invalidate cached hashes for batch
+ size_t batch_length = batch->num_rows();
+ hashes_.resize(batch_length);
+ for (int64_t i = 0; i < static_cast<int64_t>(batch_length); i +=
kMiniBatchLength) {
+ int64_t length = std::min(static_cast<int64_t>(batch_length - i),
+ static_cast<int64_t>(kMiniBatchLength));
+ for (size_t k = 0; k < indices_.size(); k++) {
+ auto array_data = batch->column_data(indices_[k]);
+ column_arrays_[k] =
+ ColumnArrayFromArrayDataAndMetadata(array_data, metadata_[k], i,
length);
+ }
+ Hashing64::HashMultiColumn(column_arrays_, &ctx_, hashes_.data() + i);
+ }
+ batch_ = batch;
+ return hashes_;
+ }
+
+ private:
+ vec_col_index_t indices_;
+ std::vector<KeyColumnMetadata> metadata_;
+ const RecordBatch* batch_;
+ std::vector<HashType> hashes_;
+ LightContext ctx_;
+ std::vector<KeyColumnArray> column_arrays_;
+ util::TempVectorStack stack_;
+};
+
class InputState {
// InputState correponds to an input
// Input record batches are queued up in InputState until processed and
// turned into output record batches.
public:
- InputState(const std::shared_ptr<arrow::Schema>& schema,
- const std::string& time_col_name, const std::string& key_col_name)
+ InputState(bool must_hash, bool nullable_by_key, KeyHasher* key_hasher,
+ const std::shared_ptr<arrow::Schema>& schema,
+ const col_index_t time_col_index, const vec_col_index_t&
key_col_index)
: queue_(),
schema_(schema),
- time_col_index_(schema->GetFieldIndex(time_col_name)),
- key_col_index_(schema->GetFieldIndex(key_col_name)) {}
+ time_col_index_(time_col_index),
+ key_col_index_(key_col_index),
+ time_type_id_(schema_->fields()[time_col_index_]->type()->id()),
+ key_type_id_(schema_->num_fields()),
+ key_hasher_(key_hasher),
+ must_hash_(must_hash),
Review Comment:
See [docs for these
fields](https://github.com/apache/arrow/pull/13880/files#diff-5789a42aebc3bd0f5a6db687c78ab0c3eef3e316982f99fe9e0ea21fabed354cR456-R463).
Basically, the type id fields are used for faster access to the key values and
the hash fields are used when hashing path (rather than the [faster
](https://github.com/apache/arrow/pull/13880/files#diff-5789a42aebc3bd0f5a6db687c78ab0c3eef3e316982f99fe9e0ea21fabed354cR306)
primitive-type
[path](https://github.com/apache/arrow/pull/13880/files#diff-5789a42aebc3bd0f5a6db687c78ab0c3eef3e316982f99fe9e0ea21fabed354cR328))
is used.
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