fdc1449392
flat_mutation_reader_v2 was introduced in a pair of commits in 2021:e3309322c3"Clone flat_mutation_reader related classes into v2 variants"08b5773c12"Adapt flat_mutation_reader_v2 to the new version of the API" as a replacement for flat_mutation_reader, using range_tombstone_change instead of range_tombstone to represent represent range tombstones. See those commits for more information. The transition was incremental; the last use of the original flat_mutation_reader was removed in 2022 in commit026f8cc1e7"db: Use mutation_partition_v2 in mvcc" In turn, flat_mutation_reader was introduced in 2017 in commit748205ca75"Introduce flat_mutation_reader" To transition from a mutation_reader that nested rows within a partition in a separate stream, to a flat reader that streamed partitions and rows in the same stream. Here, we reclaim the original name and rename the awkward flat_mutation_reader_v2 to mutation_reader. Note that mutation_fragment_v2 remains since we still use the original for compatibilty, sometimes. Some notes about the transition: - files were also renamed. In one case (flat_mutation_reader_test.cc), the rename target already existed, so we rename to mutation_reader_another_test.cc. - a namespace 'mutation_reader' with two definitions existed (in mutation_reader_fwd.hh). Its contents was folded into the mutation_reader class. As a result, a few #includes had to be adjusted. Closes scylladb/scylladb#19356
35 lines
1.2 KiB
C++
35 lines
1.2 KiB
C++
/*
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* Copyright (C) 2022-present ScyllaDB
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*/
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/*
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* SPDX-License-Identifier: AGPL-3.0-or-later
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*/
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#pragma once
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#include <seastar/core/sharded.hh>
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#include "readers/mutation_reader_fwd.hh"
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#include "schema/schema_fwd.hh"
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class reader_permit;
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/// Make a foreign_reader.
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///
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/// foreign_reader is a local representant of a reader located on a remote
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/// shard. Manages its lifecycle and takes care of seamlessly transferring
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/// produced fragments. Fragments are *copied* between the shards, a
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/// bufferful at a time.
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/// To maximize throughput read-ahead is used. After each fill_buffer() or
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/// fast_forward_to() a read-ahead (a fill_buffer() on the remote reader) is
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/// issued. This read-ahead runs in the background and is brought back to
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/// foreground on the next fill_buffer() or fast_forward_to() call.
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/// If the reader resides on this shard (the shard where make_foreign_reader()
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/// is called) there is no need to wrap it in foreign_reader, just return it as
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/// is.
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mutation_reader make_foreign_reader(schema_ptr schema,
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reader_permit permit,
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foreign_ptr<std::unique_ptr<mutation_reader>> reader,
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streamed_mutation::forwarding fwd_sm = streamed_mutation::forwarding::no);
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