mirror of
https://github.com/facebook/rocksdb.git
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36a5f8ed7f
- Replace raw slice comparison with a call to user comparator.
Added test for custom comparators.
- Fix end of namespace comments.
- Fixed bug in picking inputs for a level-0 compaction.
When finding overlapping files, the covered range may expand
as files are added to the input set. We now correctly expand
the range when this happens instead of continuing to use the
old range. For example, suppose L0 contains files with the
following ranges:
F1: a .. d
F2: c .. g
F3: f .. j
and the initial compaction target is F3. We used to search
for range f..j which yielded {F2,F3}. However we now expand
the range as soon as another file is added. In this case,
when F2 is added, we expand the range to c..j and restart the
search. That picks up file F1 as well.
This change fixes a bug related to deleted keys showing up
incorrectly after a compaction as described in Issue 44.
(Sync with upstream @25072954)
119 lines
3.6 KiB
C++
119 lines
3.6 KiB
C++
// 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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#include <stdio.h>
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#include "db/dbformat.h"
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#include "port/port.h"
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#include "util/coding.h"
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namespace leveldb {
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static uint64_t PackSequenceAndType(uint64_t seq, ValueType t) {
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assert(seq <= kMaxSequenceNumber);
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assert(t <= kValueTypeForSeek);
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return (seq << 8) | t;
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}
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void AppendInternalKey(std::string* result, const ParsedInternalKey& key) {
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result->append(key.user_key.data(), key.user_key.size());
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PutFixed64(result, PackSequenceAndType(key.sequence, key.type));
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}
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std::string ParsedInternalKey::DebugString() const {
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char buf[50];
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snprintf(buf, sizeof(buf), "' @ %llu : %d",
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(unsigned long long) sequence,
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int(type));
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std::string result = "'";
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result += user_key.ToString();
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result += buf;
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return result;
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}
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std::string InternalKey::DebugString() const {
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std::string result;
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ParsedInternalKey parsed;
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if (ParseInternalKey(rep_, &parsed)) {
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result = parsed.DebugString();
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} else {
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result = "(bad)";
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result.append(EscapeString(rep_));
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}
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return result;
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}
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const char* InternalKeyComparator::Name() const {
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return "leveldb.InternalKeyComparator";
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}
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int InternalKeyComparator::Compare(const Slice& akey, const Slice& bkey) const {
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// Order by:
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// increasing user key (according to user-supplied comparator)
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// decreasing sequence number
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// decreasing type (though sequence# should be enough to disambiguate)
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int r = user_comparator_->Compare(ExtractUserKey(akey), ExtractUserKey(bkey));
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if (r == 0) {
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const uint64_t anum = DecodeFixed64(akey.data() + akey.size() - 8);
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const uint64_t bnum = DecodeFixed64(bkey.data() + bkey.size() - 8);
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if (anum > bnum) {
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r = -1;
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} else if (anum < bnum) {
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r = +1;
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}
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}
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return r;
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}
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void InternalKeyComparator::FindShortestSeparator(
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std::string* start,
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const Slice& limit) const {
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// Attempt to shorten the user portion of the key
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Slice user_start = ExtractUserKey(*start);
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Slice user_limit = ExtractUserKey(limit);
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std::string tmp(user_start.data(), user_start.size());
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user_comparator_->FindShortestSeparator(&tmp, user_limit);
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if (user_comparator_->Compare(*start, tmp) < 0) {
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// User key has become larger. Tack on the earliest possible
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// number to the shortened user key.
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PutFixed64(&tmp, PackSequenceAndType(kMaxSequenceNumber,kValueTypeForSeek));
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assert(this->Compare(*start, tmp) < 0);
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assert(this->Compare(tmp, limit) < 0);
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start->swap(tmp);
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}
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}
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void InternalKeyComparator::FindShortSuccessor(std::string* key) const {
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Slice user_key = ExtractUserKey(*key);
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std::string tmp(user_key.data(), user_key.size());
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user_comparator_->FindShortSuccessor(&tmp);
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if (user_comparator_->Compare(user_key, tmp) < 0) {
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// User key has become larger. Tack on the earliest possible
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// number to the shortened user key.
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PutFixed64(&tmp, PackSequenceAndType(kMaxSequenceNumber,kValueTypeForSeek));
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assert(this->Compare(*key, tmp) < 0);
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key->swap(tmp);
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}
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}
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LookupKey::LookupKey(const Slice& user_key, SequenceNumber s) {
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size_t usize = user_key.size();
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size_t needed = usize + 13; // A conservative estimate
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char* dst;
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if (needed <= sizeof(space_)) {
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dst = space_;
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} else {
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dst = new char[needed];
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}
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start_ = dst;
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dst = EncodeVarint32(dst, usize + 8);
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kstart_ = dst;
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memcpy(dst, user_key.data(), usize);
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dst += usize;
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EncodeFixed64(dst, PackSequenceAndType(s, kValueTypeForSeek));
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dst += 8;
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end_ = dst;
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}
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} // namespace leveldb
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