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587 lines
15 KiB
587 lines
15 KiB
// Copyright 2017 The Prometheus Authors |
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// Licensed under the Apache License, Version 2.0 (the "License"); |
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// you may not use this file except in compliance with the License. |
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// You may obtain a copy of the License at |
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// |
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// http://www.apache.org/licenses/LICENSE-2.0 |
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// |
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// Unless required by applicable law or agreed to in writing, software |
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// distributed under the License is distributed on an "AS IS" BASIS, |
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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// See the License for the specific language governing permissions and |
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// limitations under the License. |
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package wal |
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import ( |
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"bytes" |
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"fmt" |
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"io" |
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"io/ioutil" |
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"math/rand" |
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"os" |
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"path/filepath" |
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"testing" |
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client_testutil "github.com/prometheus/client_golang/prometheus/testutil" |
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"github.com/stretchr/testify/require" |
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"go.uber.org/goleak" |
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"github.com/prometheus/prometheus/tsdb/fileutil" |
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"github.com/prometheus/prometheus/util/testutil" |
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) |
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func TestMain(m *testing.M) { |
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goleak.VerifyTestMain(m) |
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} |
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// TestWALRepair_ReadingError ensures that a repair is run for an error |
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// when reading a record. |
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func TestWALRepair_ReadingError(t *testing.T) { |
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for name, test := range map[string]struct { |
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corrSgm int // Which segment to corrupt. |
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corrFunc func(f *os.File) // Func that applies the corruption. |
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intactRecs int // Total expected records left after the repair. |
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}{ |
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"torn_last_record": { |
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2, |
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func(f *os.File) { |
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_, err := f.Seek(pageSize*2, 0) |
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require.NoError(t, err) |
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_, err = f.Write([]byte{byte(recFirst)}) |
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require.NoError(t, err) |
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}, |
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8, |
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}, |
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// Ensures that the page buffer is big enough to fit |
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// an entire page size without panicking. |
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// https://github.com/prometheus/tsdb/pull/414 |
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"bad_header": { |
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1, |
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func(f *os.File) { |
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_, err := f.Seek(pageSize, 0) |
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require.NoError(t, err) |
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_, err = f.Write([]byte{byte(recPageTerm)}) |
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require.NoError(t, err) |
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}, |
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4, |
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}, |
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"bad_fragment_sequence": { |
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1, |
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func(f *os.File) { |
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_, err := f.Seek(pageSize, 0) |
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require.NoError(t, err) |
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_, err = f.Write([]byte{byte(recLast)}) |
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require.NoError(t, err) |
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}, |
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4, |
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}, |
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"bad_fragment_flag": { |
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1, |
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func(f *os.File) { |
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_, err := f.Seek(pageSize, 0) |
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require.NoError(t, err) |
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_, err = f.Write([]byte{123}) |
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require.NoError(t, err) |
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}, |
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4, |
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}, |
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"bad_checksum": { |
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1, |
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func(f *os.File) { |
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_, err := f.Seek(pageSize+4, 0) |
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require.NoError(t, err) |
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_, err = f.Write([]byte{0}) |
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require.NoError(t, err) |
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}, |
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4, |
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}, |
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"bad_length": { |
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1, |
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func(f *os.File) { |
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_, err := f.Seek(pageSize+2, 0) |
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require.NoError(t, err) |
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_, err = f.Write([]byte{0}) |
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require.NoError(t, err) |
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}, |
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4, |
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}, |
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"bad_content": { |
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1, |
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func(f *os.File) { |
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_, err := f.Seek(pageSize+100, 0) |
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require.NoError(t, err) |
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_, err = f.Write([]byte("beef")) |
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require.NoError(t, err) |
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}, |
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4, |
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}, |
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} { |
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t.Run(name, func(t *testing.T) { |
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dir, err := ioutil.TempDir("", "wal_repair") |
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require.NoError(t, err) |
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defer func() { |
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require.NoError(t, os.RemoveAll(dir)) |
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}() |
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// We create 3 segments with 3 records each and |
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// then corrupt a given record in a given segment. |
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// As a result we want a repaired WAL with given intact records. |
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segSize := 3 * pageSize |
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w, err := NewSize(nil, nil, dir, segSize, false) |
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require.NoError(t, err) |
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var records [][]byte |
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for i := 1; i <= 9; i++ { |
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b := make([]byte, pageSize-recordHeaderSize) |
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b[0] = byte(i) |
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records = append(records, b) |
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require.NoError(t, w.Log(b)) |
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} |
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first, last, err := Segments(w.Dir()) |
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require.NoError(t, err) |
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require.Equal(t, 3, 1+last-first, "wal creation didn't result in expected number of segments") |
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require.NoError(t, w.Close()) |
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f, err := os.OpenFile(SegmentName(dir, test.corrSgm), os.O_RDWR, 0666) |
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require.NoError(t, err) |
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// Apply corruption function. |
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test.corrFunc(f) |
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require.NoError(t, f.Close()) |
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w, err = NewSize(nil, nil, dir, segSize, false) |
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require.NoError(t, err) |
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defer w.Close() |
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first, last, err = Segments(w.Dir()) |
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require.NoError(t, err) |
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// Backfill segments from the most recent checkpoint onwards. |
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for i := first; i <= last; i++ { |
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s, err := OpenReadSegment(SegmentName(w.Dir(), i)) |
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require.NoError(t, err) |
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sr := NewSegmentBufReader(s) |
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require.NoError(t, err) |
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r := NewReader(sr) |
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for r.Next() { |
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} |
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//Close the segment so we don't break things on Windows. |
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s.Close() |
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// No corruption in this segment. |
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if r.Err() == nil { |
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continue |
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} |
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require.NoError(t, w.Repair(r.Err())) |
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break |
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} |
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sr, err := NewSegmentsReader(dir) |
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require.NoError(t, err) |
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defer sr.Close() |
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r := NewReader(sr) |
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var result [][]byte |
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for r.Next() { |
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var b []byte |
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result = append(result, append(b, r.Record()...)) |
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} |
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require.NoError(t, r.Err()) |
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require.Equal(t, test.intactRecs, len(result), "Wrong number of intact records") |
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for i, r := range result { |
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if !bytes.Equal(records[i], r) { |
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t.Fatalf("record %d diverges: want %x, got %x", i, records[i][:10], r[:10]) |
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} |
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} |
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// Make sure there is a new 0 size Segment after the corrupted Segment. |
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_, last, err = Segments(w.Dir()) |
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require.NoError(t, err) |
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require.Equal(t, test.corrSgm+1, last) |
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fi, err := os.Stat(SegmentName(dir, last)) |
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require.NoError(t, err) |
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require.Equal(t, int64(0), fi.Size()) |
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}) |
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} |
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} |
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// TestCorruptAndCarryOn writes a multi-segment WAL; corrupts the first segment and |
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// ensures that an error during reading that segment are correctly repaired before |
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// moving to write more records to the WAL. |
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func TestCorruptAndCarryOn(t *testing.T) { |
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dir, err := ioutil.TempDir("", "wal_repair") |
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require.NoError(t, err) |
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defer func() { |
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require.NoError(t, os.RemoveAll(dir)) |
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}() |
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var ( |
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logger = testutil.NewLogger(t) |
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segmentSize = pageSize * 3 |
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recordSize = (pageSize / 3) - recordHeaderSize |
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) |
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// Produce a WAL with a two segments of 3 pages with 3 records each, |
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// so when we truncate the file we're guaranteed to split a record. |
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{ |
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w, err := NewSize(logger, nil, dir, segmentSize, false) |
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require.NoError(t, err) |
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for i := 0; i < 18; i++ { |
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buf := make([]byte, recordSize) |
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_, err := rand.Read(buf) |
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require.NoError(t, err) |
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err = w.Log(buf) |
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require.NoError(t, err) |
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} |
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err = w.Close() |
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require.NoError(t, err) |
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} |
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// Check all the segments are the correct size. |
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{ |
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segments, err := listSegments(dir) |
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require.NoError(t, err) |
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for _, segment := range segments { |
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f, err := os.OpenFile(filepath.Join(dir, fmt.Sprintf("%08d", segment.index)), os.O_RDONLY, 0666) |
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require.NoError(t, err) |
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fi, err := f.Stat() |
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require.NoError(t, err) |
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t.Log("segment", segment.index, "size", fi.Size()) |
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require.Equal(t, int64(segmentSize), fi.Size()) |
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err = f.Close() |
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require.NoError(t, err) |
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} |
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} |
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// Truncate the first file, splitting the middle record in the second |
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// page in half, leaving 4 valid records. |
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{ |
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f, err := os.OpenFile(filepath.Join(dir, fmt.Sprintf("%08d", 0)), os.O_RDWR, 0666) |
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require.NoError(t, err) |
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fi, err := f.Stat() |
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require.NoError(t, err) |
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require.Equal(t, int64(segmentSize), fi.Size()) |
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err = f.Truncate(int64(segmentSize / 2)) |
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require.NoError(t, err) |
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err = f.Close() |
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require.NoError(t, err) |
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} |
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// Now try and repair this WAL, and write 5 more records to it. |
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{ |
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sr, err := NewSegmentsReader(dir) |
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require.NoError(t, err) |
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reader := NewReader(sr) |
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i := 0 |
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for ; i < 4 && reader.Next(); i++ { |
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require.Equal(t, recordSize, len(reader.Record())) |
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} |
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require.Equal(t, 4, i, "not enough records") |
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require.False(t, reader.Next(), "unexpected record") |
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corruptionErr := reader.Err() |
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require.Error(t, corruptionErr) |
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err = sr.Close() |
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require.NoError(t, err) |
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w, err := NewSize(logger, nil, dir, segmentSize, false) |
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require.NoError(t, err) |
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err = w.Repair(corruptionErr) |
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require.NoError(t, err) |
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// Ensure that we have a completely clean slate after repairing. |
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require.Equal(t, w.segment.Index(), 1) // We corrupted segment 0. |
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require.Equal(t, w.donePages, 0) |
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for i := 0; i < 5; i++ { |
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buf := make([]byte, recordSize) |
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_, err := rand.Read(buf) |
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require.NoError(t, err) |
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err = w.Log(buf) |
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require.NoError(t, err) |
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} |
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err = w.Close() |
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require.NoError(t, err) |
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} |
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// Replay the WAL. Should get 9 records. |
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{ |
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sr, err := NewSegmentsReader(dir) |
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require.NoError(t, err) |
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reader := NewReader(sr) |
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i := 0 |
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for ; i < 9 && reader.Next(); i++ { |
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require.Equal(t, recordSize, len(reader.Record())) |
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} |
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require.Equal(t, 9, i, "wrong number of records") |
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require.False(t, reader.Next(), "unexpected record") |
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require.Equal(t, nil, reader.Err()) |
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sr.Close() |
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} |
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} |
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// TestClose ensures that calling Close more than once doesn't panic and doesn't block. |
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func TestClose(t *testing.T) { |
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dir, err := ioutil.TempDir("", "wal_repair") |
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require.NoError(t, err) |
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defer func() { |
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require.NoError(t, os.RemoveAll(dir)) |
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}() |
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w, err := NewSize(nil, nil, dir, pageSize, false) |
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require.NoError(t, err) |
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require.NoError(t, w.Close()) |
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require.Error(t, w.Close()) |
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} |
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func TestSegmentMetric(t *testing.T) { |
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var ( |
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segmentSize = pageSize |
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recordSize = (pageSize / 2) - recordHeaderSize |
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) |
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dir, err := ioutil.TempDir("", "segment_metric") |
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require.NoError(t, err) |
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defer func() { |
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require.NoError(t, os.RemoveAll(dir)) |
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}() |
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w, err := NewSize(nil, nil, dir, segmentSize, false) |
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require.NoError(t, err) |
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initialSegment := client_testutil.ToFloat64(w.metrics.currentSegment) |
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// Write 3 records, each of which is half the segment size, meaning we should rotate to the next segment. |
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for i := 0; i < 3; i++ { |
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buf := make([]byte, recordSize) |
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_, err := rand.Read(buf) |
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require.NoError(t, err) |
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err = w.Log(buf) |
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require.NoError(t, err) |
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} |
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require.Equal(t, initialSegment+1, client_testutil.ToFloat64(w.metrics.currentSegment), "segment metric did not increment after segment rotation") |
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require.NoError(t, w.Close()) |
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} |
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func TestCompression(t *testing.T) { |
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bootstrap := func(compressed bool) string { |
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const ( |
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segmentSize = pageSize |
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recordSize = (pageSize / 2) - recordHeaderSize |
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records = 100 |
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) |
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dirPath, err := ioutil.TempDir("", fmt.Sprintf("TestCompression_%t", compressed)) |
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require.NoError(t, err) |
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w, err := NewSize(nil, nil, dirPath, segmentSize, compressed) |
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require.NoError(t, err) |
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buf := make([]byte, recordSize) |
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for i := 0; i < records; i++ { |
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require.NoError(t, w.Log(buf)) |
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} |
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require.NoError(t, w.Close()) |
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return dirPath |
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} |
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dirCompressed := bootstrap(true) |
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defer func() { |
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require.NoError(t, os.RemoveAll(dirCompressed)) |
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}() |
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dirUnCompressed := bootstrap(false) |
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defer func() { |
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require.NoError(t, os.RemoveAll(dirUnCompressed)) |
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}() |
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uncompressedSize, err := fileutil.DirSize(dirUnCompressed) |
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require.NoError(t, err) |
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compressedSize, err := fileutil.DirSize(dirCompressed) |
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require.NoError(t, err) |
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require.Greater(t, float64(uncompressedSize)*0.75, float64(compressedSize), "Compressing zeroes should save at least 25%% space - uncompressedSize: %d, compressedSize: %d", uncompressedSize, compressedSize) |
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} |
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func TestLogPartialWrite(t *testing.T) { |
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const segmentSize = pageSize * 2 |
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record := []byte{1, 2, 3, 4, 5} |
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tests := map[string]struct { |
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numRecords int |
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faultyRecord int |
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}{ |
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"partial write when logging first record in a page": { |
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numRecords: 10, |
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faultyRecord: 1, |
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}, |
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"partial write when logging record in the middle of a page": { |
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numRecords: 10, |
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faultyRecord: 3, |
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}, |
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"partial write when logging last record of a page": { |
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numRecords: (pageSize / (recordHeaderSize + len(record))) + 10, |
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faultyRecord: pageSize / (recordHeaderSize + len(record)), |
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}, |
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// TODO the current implementation suffers this: |
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//"partial write when logging a record overlapping two pages": { |
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// numRecords: (pageSize / (recordHeaderSize + len(record))) + 10, |
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// faultyRecord: pageSize/(recordHeaderSize+len(record)) + 1, |
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//}, |
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} |
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for testName, testData := range tests { |
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t.Run(testName, func(t *testing.T) { |
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dirPath, err := ioutil.TempDir("", "logpartialwrite") |
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require.NoError(t, err) |
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defer func() { require.NoError(t, os.RemoveAll(dirPath)) }() |
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w, err := NewSize(nil, nil, dirPath, segmentSize, false) |
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require.NoError(t, err) |
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// Replace the underlying segment file with a mocked one that injects a failure. |
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w.segment.SegmentFile = &faultySegmentFile{ |
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SegmentFile: w.segment.SegmentFile, |
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writeFailureAfter: ((recordHeaderSize + len(record)) * (testData.faultyRecord - 1)) + 2, |
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writeFailureErr: io.ErrShortWrite, |
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} |
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for i := 1; i <= testData.numRecords; i++ { |
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if err := w.Log(record); i == testData.faultyRecord { |
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require.Error(t, io.ErrShortWrite, err) |
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} else { |
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require.NoError(t, err) |
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} |
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} |
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require.NoError(t, w.Close()) |
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// Read it back. We expect no corruption. |
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s, err := OpenReadSegment(SegmentName(dirPath, 0)) |
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require.NoError(t, err) |
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defer func() { require.NoError(t, s.Close()) }() |
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r := NewReader(NewSegmentBufReader(s)) |
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for i := 0; i < testData.numRecords; i++ { |
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require.True(t, r.Next()) |
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require.NoError(t, r.Err()) |
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require.Equal(t, record, r.Record()) |
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} |
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require.False(t, r.Next()) |
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require.NoError(t, r.Err()) |
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}) |
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} |
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} |
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type faultySegmentFile struct { |
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SegmentFile |
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written int |
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writeFailureAfter int |
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writeFailureErr error |
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} |
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func (f *faultySegmentFile) Write(p []byte) (int, error) { |
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if f.writeFailureAfter >= 0 && f.writeFailureAfter < f.written+len(p) { |
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partialLen := f.writeFailureAfter - f.written |
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if partialLen <= 0 || partialLen >= len(p) { |
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partialLen = 1 |
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} |
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// Inject failure. |
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n, _ := f.SegmentFile.Write(p[:partialLen]) |
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f.written += n |
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f.writeFailureAfter = -1 |
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return n, f.writeFailureErr |
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} |
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// Proxy the write to the underlying file. |
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n, err := f.SegmentFile.Write(p) |
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f.written += n |
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return n, err |
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} |
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func BenchmarkWAL_LogBatched(b *testing.B) { |
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for _, compress := range []bool{true, false} { |
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b.Run(fmt.Sprintf("compress=%t", compress), func(b *testing.B) { |
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dir, err := ioutil.TempDir("", "bench_logbatch") |
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require.NoError(b, err) |
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defer func() { |
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require.NoError(b, os.RemoveAll(dir)) |
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}() |
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w, err := New(nil, nil, dir, compress) |
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require.NoError(b, err) |
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defer w.Close() |
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var buf [2048]byte |
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var recs [][]byte |
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b.SetBytes(2048) |
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for i := 0; i < b.N; i++ { |
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recs = append(recs, buf[:]) |
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if len(recs) < 1000 { |
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continue |
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} |
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err := w.Log(recs...) |
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require.NoError(b, err) |
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recs = recs[:0] |
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} |
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// Stop timer to not count fsync time on close. |
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// If it's counted batched vs. single benchmarks are very similar but |
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// do not show burst throughput well. |
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b.StopTimer() |
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}) |
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} |
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} |
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func BenchmarkWAL_Log(b *testing.B) { |
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for _, compress := range []bool{true, false} { |
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b.Run(fmt.Sprintf("compress=%t", compress), func(b *testing.B) { |
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dir, err := ioutil.TempDir("", "bench_logsingle") |
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require.NoError(b, err) |
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defer func() { |
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require.NoError(b, os.RemoveAll(dir)) |
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}() |
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w, err := New(nil, nil, dir, compress) |
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require.NoError(b, err) |
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defer w.Close() |
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var buf [2048]byte |
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b.SetBytes(2048) |
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for i := 0; i < b.N; i++ { |
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err := w.Log(buf[:]) |
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require.NoError(b, err) |
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} |
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// Stop timer to not count fsync time on close. |
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// If it's counted batched vs. single benchmarks are very similar but |
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// do not show burst throughput well. |
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b.StopTimer() |
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}) |
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} |
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}
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