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scylladb/query_result_merger.hh
Avi Kivity f3eade2f62 treewide: relicense to ScyllaDB-Source-Available-1.0
Drop the AGPL license in favor of a source-available license.
See the blog post [1] for details.

[1] https://www.scylladb.com/2024/12/18/why-were-moving-to-a-source-available-license/
2024-12-18 17:45:13 +02:00

46 lines
1.2 KiB
C++

/*
* Copyright (C) 2015-present ScyllaDB
*/
/*
* SPDX-License-Identifier: LicenseRef-ScyllaDB-Source-Available-1.0
*/
#pragma once
#include <seastar/core/distributed.hh>
#include "query-result.hh"
namespace query {
// Merges non-overlapping results into one
// Implements @Reducer concept from distributed.hh
class result_merger {
std::vector<foreign_ptr<lw_shared_ptr<query::result>>> _partial;
const uint64_t _max_rows;
const uint32_t _max_partitions;
public:
explicit result_merger(uint64_t max_rows, uint32_t max_partitions)
: _max_rows(max_rows)
, _max_partitions(max_partitions)
{ }
void reserve(size_t size) {
_partial.reserve(size);
}
void operator()(foreign_ptr<lw_shared_ptr<query::result>> r) {
if (!_partial.empty() && _partial.back()->is_short_read()) {
return;
}
_partial.emplace_back(std::move(r));
}
// FIXME: Eventually we should return a composite_query_result here
// which holds the vector of query results and which can be quickly turned
// into packet fragments by the transport layer without copying the data.
foreign_ptr<lw_shared_ptr<query::result>> get();
};
}