47c4191fe8
Summary: There is a new option called hybrid_mode which, when switched on, causes HBase style compactions. Files from L0 are compacted back into L0. This meat of this compaction algorithm is in PickCompactionHybrid(). All files reside in L0. That means all files have overlapping keys. Each file has a time-bound, i.e. each file contains a range of keys that were inserted around the same time. The start-seqno and the end-seqno refers to the timeframe when these keys were inserted. Files that have contiguous seqno are compacted together into a larger file. All files are ordered from most recent to the oldest. The current compaction algorithm starts to look for candidate files starting from the most recent file. It continues to add more files to the same compaction run as long as the sum of the files chosen till now is smaller than the next candidate file size. This logic needs to be debated and validated. The above logic should reduce write amplification to a large extent... will publish numbers shortly. Test Plan: dbstress runs for 6 hours with no data corruption (tested so far). Differential Revision: https://reviews.facebook.net/D11289
49 lines
1.4 KiB
C++
49 lines
1.4 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 "db/version_edit.h"
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#include "util/testharness.h"
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namespace leveldb {
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static void TestEncodeDecode(const VersionEdit& edit) {
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std::string encoded, encoded2;
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edit.EncodeTo(&encoded);
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VersionEdit parsed(7);
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Status s = parsed.DecodeFrom(encoded);
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ASSERT_TRUE(s.ok()) << s.ToString();
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parsed.EncodeTo(&encoded2);
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ASSERT_EQ(encoded, encoded2);
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}
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class VersionEditTest { };
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TEST(VersionEditTest, EncodeDecode) {
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static const uint64_t kBig = 1ull << 50;
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VersionEdit edit(7);
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for (int i = 0; i < 4; i++) {
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TestEncodeDecode(edit);
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edit.AddFile(3, kBig + 300 + i, kBig + 400 + i,
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InternalKey("foo", kBig + 500 + i, kTypeValue),
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InternalKey("zoo", kBig + 600 + i, kTypeDeletion),
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kBig + 500 + i,
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kBig + 600 + i);
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edit.DeleteFile(4, kBig + 700 + i);
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edit.SetCompactPointer(i, InternalKey("x", kBig + 900 + i, kTypeValue));
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}
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edit.SetComparatorName("foo");
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edit.SetLogNumber(kBig + 100);
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edit.SetNextFile(kBig + 200);
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edit.SetLastSequence(kBig + 1000);
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TestEncodeDecode(edit);
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}
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} // namespace leveldb
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int main(int argc, char** argv) {
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return leveldb::test::RunAllTests();
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}
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