69a385fd9d
Schema related files are moved there. This excludes schema files that also interact with mutations, because the mutation module depends on the schema. Those files will have to go into a separate module. Closes #12858
35 lines
1.2 KiB
C++
35 lines
1.2 KiB
C++
/*
|
|
* Copyright (C) 2022-present ScyllaDB
|
|
*/
|
|
|
|
/*
|
|
* SPDX-License-Identifier: AGPL-3.0-or-later
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include <seastar/core/sharded.hh>
|
|
|
|
#include "readers/flat_mutation_reader_fwd.hh"
|
|
#include "schema/schema_fwd.hh"
|
|
|
|
class reader_permit;
|
|
|
|
/// Make a foreign_reader.
|
|
///
|
|
/// foreign_reader is a local representant of a reader located on a remote
|
|
/// shard. Manages its lifecycle and takes care of seamlessly transferring
|
|
/// produced fragments. Fragments are *copied* between the shards, a
|
|
/// bufferful at a time.
|
|
/// To maximize throughput read-ahead is used. After each fill_buffer() or
|
|
/// fast_forward_to() a read-ahead (a fill_buffer() on the remote reader) is
|
|
/// issued. This read-ahead runs in the background and is brough back to
|
|
/// foreground on the next fill_buffer() or fast_forward_to() call.
|
|
/// If the reader resides on this shard (the shard where make_foreign_reader()
|
|
/// is called) there is no need to wrap it in foreign_reader, just return it as
|
|
/// is.
|
|
flat_mutation_reader_v2 make_foreign_reader(schema_ptr schema,
|
|
reader_permit permit,
|
|
foreign_ptr<std::unique_ptr<flat_mutation_reader_v2>> reader,
|
|
streamed_mutation::forwarding fwd_sm = streamed_mutation::forwarding::no);
|