48cf039064
Summary: Introducing blob_db::TTLExtractor to replace extract_ttl_fn. The TTL extractor can be use to extract TTL from keys insert with Put or WriteBatch. Change over existing extract_ttl_fn are: * If value is changed, it will be return via std::string* (rather than Slice*). With Slice* the new value has to be part of the existing value. With std::string* the limitation is removed. * It can optionally return TTL or expiration. Other changes in this PR: * replace `std::chrono::system_clock` with `Env::NowMicros` so that I can mock time in tests. * add several TTL tests. * other minor naming change. Closes https://github.com/facebook/rocksdb/pull/2659 Differential Revision: D5512627 Pulled By: yiwu-arbug fbshipit-source-id: 0dfcb00d74d060b8534c6130c808e4d5d0a54440
44 lines
1.8 KiB
C++
44 lines
1.8 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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#pragma once
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#include <memory>
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#include <string>
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#include "rocksdb/slice.h"
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namespace rocksdb {
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namespace blob_db {
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// TTLExtractor allow applications to extract TTL from key-value pairs.
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// This useful for applications using Put or WriteBatch to write keys and
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// don't intend to migrate to PutWithTTL or PutUntil.
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//
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// Applications can implement either ExtractTTL or ExtractExpiration. If both
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// are implemented, ExtractExpiration will take precedence.
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class TTLExtractor {
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public:
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// Extract TTL from key-value pair.
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// Return true if the key has TTL, false otherwise. If key has TTL,
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// TTL is pass back through ttl. The method can optionally modify the value,
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// pass the result back through new_value, and also set value_changed to true.
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virtual bool ExtractTTL(const Slice& key, const Slice& value, uint64_t* ttl,
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std::string* new_value, bool* value_changed);
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// Extract expiration time from key-value pair.
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// Return true if the key has expiration time, false otherwise. If key has
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// expiration time, it is pass back through expiration. The method can
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// optionally modify the value, pass the result back through new_value,
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// and also set value_changed to true.
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virtual bool ExtractExpiration(const Slice& key, const Slice& value,
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uint64_t now, uint64_t* expiration,
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std::string* new_value, bool* value_changed);
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virtual ~TTLExtractor() = default;
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};
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} // namespace blob_db
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} // namespace rocksdb
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