408205a36b
Summary: Previously in https://github.com/facebook/rocksdb/pull/3601 bloom filter will only be checked if `prefix_extractor` in the mutable_cf_options matches the one found in the SST file. This PR relaxes the requirement by checking if all keys in the range [user_key, iterate_upper_bound) all share the same prefix after transforming using the BF in the SST file. If so, the bloom filter is considered compatible and will continue to be looked at. Closes https://github.com/facebook/rocksdb/pull/3899 Differential Revision: D8157459 Pulled By: miasantreble fbshipit-source-id: 18d17cba56a1005162f8d5db7a27aba277089c41
91 lines
3.4 KiB
C++
91 lines
3.4 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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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#ifndef STORAGE_ROCKSDB_INCLUDE_COMPARATOR_H_
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#define STORAGE_ROCKSDB_INCLUDE_COMPARATOR_H_
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#include <string>
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namespace rocksdb {
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class Slice;
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// A Comparator object provides a total order across slices that are
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// used as keys in an sstable or a database. A Comparator implementation
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// must be thread-safe since rocksdb may invoke its methods concurrently
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// from multiple threads.
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class Comparator {
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public:
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virtual ~Comparator() {}
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// Three-way comparison. Returns value:
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// < 0 iff "a" < "b",
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// == 0 iff "a" == "b",
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// > 0 iff "a" > "b"
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virtual int Compare(const Slice& a, const Slice& b) const = 0;
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// Compares two slices for equality. The following invariant should always
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// hold (and is the default implementation):
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// Equal(a, b) iff Compare(a, b) == 0
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// Overwrite only if equality comparisons can be done more efficiently than
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// three-way comparisons.
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virtual bool Equal(const Slice& a, const Slice& b) const {
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return Compare(a, b) == 0;
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}
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// The name of the comparator. Used to check for comparator
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// mismatches (i.e., a DB created with one comparator is
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// accessed using a different comparator.
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//
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// The client of this package should switch to a new name whenever
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// the comparator implementation changes in a way that will cause
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// the relative ordering of any two keys to change.
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//
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// Names starting with "rocksdb." are reserved and should not be used
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// by any clients of this package.
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virtual const char* Name() const = 0;
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// Advanced functions: these are used to reduce the space requirements
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// for internal data structures like index blocks.
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// If *start < limit, changes *start to a short string in [start,limit).
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// Simple comparator implementations may return with *start unchanged,
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// i.e., an implementation of this method that does nothing is correct.
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virtual void FindShortestSeparator(
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std::string* start,
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const Slice& limit) const = 0;
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// Changes *key to a short string >= *key.
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// Simple comparator implementations may return with *key unchanged,
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// i.e., an implementation of this method that does nothing is correct.
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virtual void FindShortSuccessor(std::string* key) const = 0;
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// if it is a wrapped comparator, may return the root one.
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// return itself it is not wrapped.
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virtual const Comparator* GetRootComparator() const { return this; }
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// given two keys, determine if t is the successor of s
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virtual bool IsSameLengthImmediateSuccessor(const Slice& /*s*/,
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const Slice& /*t*/) const {
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return false;
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}
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};
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// Return a builtin comparator that uses lexicographic byte-wise
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// ordering. The result remains the property of this module and
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// must not be deleted.
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extern const Comparator* BytewiseComparator();
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// Return a builtin comparator that uses reverse lexicographic byte-wise
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// ordering.
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extern const Comparator* ReverseBytewiseComparator();
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} // namespace rocksdb
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#endif // STORAGE_ROCKSDB_INCLUDE_COMPARATOR_H_
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