ceremonyclient/pebble/metrics.go

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2024-01-03 07:31:42 +00:00
// Copyright 2019 The LevelDB-Go and Pebble Authors. All rights reserved. Use
// of this source code is governed by a BSD-style license that can be found in
// the LICENSE file.
package pebble
import (
"fmt"
"math"
"time"
"github.com/cockroachdb/pebble/internal/base"
"github.com/cockroachdb/pebble/internal/cache"
"github.com/cockroachdb/pebble/internal/humanize"
"github.com/cockroachdb/pebble/objstorage/objstorageprovider/sharedcache"
"github.com/cockroachdb/pebble/record"
"github.com/cockroachdb/pebble/sstable"
"github.com/cockroachdb/redact"
"github.com/prometheus/client_golang/prometheus"
)
// CacheMetrics holds metrics for the block and table cache.
type CacheMetrics = cache.Metrics
// FilterMetrics holds metrics for the filter policy
type FilterMetrics = sstable.FilterMetrics
// ThroughputMetric is a cumulative throughput metric. See the detailed
// comment in base.
type ThroughputMetric = base.ThroughputMetric
// SecondaryCacheMetrics holds metrics for the persistent secondary cache
// that caches commonly accessed blocks from blob storage on a local
// file system.
type SecondaryCacheMetrics = sharedcache.Metrics
// LevelMetrics holds per-level metrics such as the number of files and total
// size of the files, and compaction related metrics.
type LevelMetrics struct {
// The number of sublevels within the level. The sublevel count corresponds
// to the read amplification for the level. An empty level will have a
// sublevel count of 0, implying no read amplification. Only L0 will have
// a sublevel count other than 0 or 1.
Sublevels int32
// The total number of files in the level.
NumFiles int64
// The total number of virtual sstables in the level.
NumVirtualFiles uint64
// The total size in bytes of the files in the level.
Size int64
// The total size of the virtual sstables in the level.
VirtualSize uint64
// The level's compaction score. This is the compensatedScoreRatio in the
// candidateLevelInfo.
Score float64
// The number of incoming bytes from other levels read during
// compactions. This excludes bytes moved and bytes ingested. For L0 this is
// the bytes written to the WAL.
BytesIn uint64
// The number of bytes ingested. The sibling metric for tables is
// TablesIngested.
BytesIngested uint64
// The number of bytes moved into the level by a "move" compaction. The
// sibling metric for tables is TablesMoved.
BytesMoved uint64
// The number of bytes read for compactions at the level. This includes bytes
// read from other levels (BytesIn), as well as bytes read for the level.
BytesRead uint64
// The number of bytes written during compactions. The sibling
// metric for tables is TablesCompacted. This metric may be summed
// with BytesFlushed to compute the total bytes written for the level.
BytesCompacted uint64
// The number of bytes written during flushes. The sibling
// metrics for tables is TablesFlushed. This metric is always
// zero for all levels other than L0.
BytesFlushed uint64
// The number of sstables compacted to this level.
TablesCompacted uint64
// The number of sstables flushed to this level.
TablesFlushed uint64
// The number of sstables ingested into the level.
TablesIngested uint64
// The number of sstables moved to this level by a "move" compaction.
TablesMoved uint64
MultiLevel struct {
// BytesInTop are the total bytes in a multilevel compaction coming from the top level.
BytesInTop uint64
// BytesIn, exclusively for multiLevel compactions.
BytesIn uint64
// BytesRead, exclusively for multilevel compactions.
BytesRead uint64
}
// Additional contains misc additional metrics that are not always printed.
Additional struct {
// The sum of Properties.ValueBlocksSize for all the sstables in this
// level. Printed by LevelMetrics.format iff there is at least one level
// with a non-zero value.
ValueBlocksSize uint64
// Cumulative metrics about bytes written to data blocks and value blocks,
// via compactions (except move compactions) or flushes. Not printed by
// LevelMetrics.format, but are available to sophisticated clients.
BytesWrittenDataBlocks uint64
BytesWrittenValueBlocks uint64
}
}
// Add updates the counter metrics for the level.
func (m *LevelMetrics) Add(u *LevelMetrics) {
m.NumFiles += u.NumFiles
m.NumVirtualFiles += u.NumVirtualFiles
m.VirtualSize += u.VirtualSize
m.Size += u.Size
m.BytesIn += u.BytesIn
m.BytesIngested += u.BytesIngested
m.BytesMoved += u.BytesMoved
m.BytesRead += u.BytesRead
m.BytesCompacted += u.BytesCompacted
m.BytesFlushed += u.BytesFlushed
m.TablesCompacted += u.TablesCompacted
m.TablesFlushed += u.TablesFlushed
m.TablesIngested += u.TablesIngested
m.TablesMoved += u.TablesMoved
m.MultiLevel.BytesInTop += u.MultiLevel.BytesInTop
m.MultiLevel.BytesRead += u.MultiLevel.BytesRead
m.MultiLevel.BytesIn += u.MultiLevel.BytesIn
m.Additional.BytesWrittenDataBlocks += u.Additional.BytesWrittenDataBlocks
m.Additional.BytesWrittenValueBlocks += u.Additional.BytesWrittenValueBlocks
m.Additional.ValueBlocksSize += u.Additional.ValueBlocksSize
}
// WriteAmp computes the write amplification for compactions at this
// level. Computed as (BytesFlushed + BytesCompacted) / BytesIn.
func (m *LevelMetrics) WriteAmp() float64 {
if m.BytesIn == 0 {
return 0
}
return float64(m.BytesFlushed+m.BytesCompacted) / float64(m.BytesIn)
}
// Metrics holds metrics for various subsystems of the DB such as the Cache,
// Compactions, WAL, and per-Level metrics.
//
// TODO(peter): The testing of these metrics is relatively weak. There should
// be testing that performs various operations on a DB and verifies that the
// metrics reflect those operations.
type Metrics struct {
BlockCache CacheMetrics
Compact struct {
// The total number of compactions, and per-compaction type counts.
Count int64
DefaultCount int64
DeleteOnlyCount int64
ElisionOnlyCount int64
MoveCount int64
ReadCount int64
RewriteCount int64
MultiLevelCount int64
CounterLevelCount int64
// An estimate of the number of bytes that need to be compacted for the LSM
// to reach a stable state.
EstimatedDebt uint64
// Number of bytes present in sstables being written by in-progress
// compactions. This value will be zero if there are no in-progress
// compactions.
InProgressBytes int64
// Number of compactions that are in-progress.
NumInProgress int64
// MarkedFiles is a count of files that are marked for
// compaction. Such files are compacted in a rewrite compaction
// when no other compactions are picked.
MarkedFiles int
// Duration records the cumulative duration of all compactions since the
// database was opened.
Duration time.Duration
}
Ingest struct {
// The total number of ingestions
Count uint64
}
Flush struct {
// The total number of flushes.
Count int64
WriteThroughput ThroughputMetric
// Number of flushes that are in-progress. In the current implementation
// this will always be zero or one.
NumInProgress int64
// AsIngestCount is a monotonically increasing counter of flush operations
// handling ingested tables.
AsIngestCount uint64
// AsIngestCount is a monotonically increasing counter of tables ingested as
// flushables.
AsIngestTableCount uint64
// AsIngestBytes is a monotonically increasing counter of the bytes flushed
// for flushables that originated as ingestion operations.
AsIngestBytes uint64
}
Filter FilterMetrics
Levels [numLevels]LevelMetrics
MemTable struct {
// The number of bytes allocated by memtables and large (flushable)
// batches.
Size uint64
// The count of memtables.
Count int64
// The number of bytes present in zombie memtables which are no longer
// referenced by the current DB state. An unbounded number of memtables
// may be zombie if they're still in use by an iterator. One additional
// memtable may be zombie if it's no longer in use and waiting to be
// recycled.
ZombieSize uint64
// The count of zombie memtables.
ZombieCount int64
}
Keys struct {
// The approximate count of internal range key set keys in the database.
RangeKeySetsCount uint64
// The approximate count of internal tombstones (DEL, SINGLEDEL and
// RANGEDEL key kinds) within the database.
TombstoneCount uint64
// A cumulative total number of missized DELSIZED keys encountered by
// compactions since the database was opened.
MissizedTombstonesCount uint64
}
Snapshots struct {
// The number of currently open snapshots.
Count int
// The sequence number of the earliest, currently open snapshot.
EarliestSeqNum uint64
// A running tally of keys written to sstables during flushes or
// compactions that would've been elided if it weren't for open
// snapshots.
PinnedKeys uint64
// A running cumulative sum of the size of keys and values written to
// sstables during flushes or compactions that would've been elided if
// it weren't for open snapshots.
PinnedSize uint64
}
Table struct {
// The number of bytes present in obsolete tables which are no longer
// referenced by the current DB state or any open iterators.
ObsoleteSize uint64
// The count of obsolete tables.
ObsoleteCount int64
// The number of bytes present in zombie tables which are no longer
// referenced by the current DB state but are still in use by an iterator.
ZombieSize uint64
// The count of zombie tables.
ZombieCount int64
// The count of the backing sstables.
BackingTableCount uint64
// The sum of the sizes of the all of the backing sstables.
BackingTableSize uint64
}
TableCache CacheMetrics
// Count of the number of open sstable iterators.
TableIters int64
// Uptime is the total time since this DB was opened.
Uptime time.Duration
WAL struct {
// Number of live WAL files.
Files int64
// Number of obsolete WAL files.
ObsoleteFiles int64
// Physical size of the obsolete WAL files.
ObsoletePhysicalSize uint64
// Size of the live data in the WAL files. Note that with WAL file
// recycling this is less than the actual on-disk size of the WAL files.
Size uint64
// Physical size of the WAL files on-disk. With WAL file recycling,
// this is greater than the live data in WAL files.
PhysicalSize uint64
// Number of logical bytes written to the WAL.
BytesIn uint64
// Number of bytes written to the WAL.
BytesWritten uint64
}
LogWriter struct {
FsyncLatency prometheus.Histogram
record.LogWriterMetrics
}
CategoryStats []sstable.CategoryStatsAggregate
SecondaryCacheMetrics SecondaryCacheMetrics
private struct {
optionsFileSize uint64
manifestFileSize uint64
}
}
var (
// FsyncLatencyBuckets are prometheus histogram buckets suitable for a histogram
// that records latencies for fsyncs.
FsyncLatencyBuckets = append(
prometheus.LinearBuckets(0.0, float64(time.Microsecond*100), 50),
prometheus.ExponentialBucketsRange(float64(time.Millisecond*5), float64(10*time.Second), 50)...,
)
// SecondaryCacheIOBuckets exported to enable exporting from package pebble to
// enable exporting metrics with below buckets in CRDB.
SecondaryCacheIOBuckets = sharedcache.IOBuckets
// SecondaryCacheChannelWriteBuckets exported to enable exporting from package
// pebble to enable exporting metrics with below buckets in CRDB.
SecondaryCacheChannelWriteBuckets = sharedcache.ChannelWriteBuckets
)
// DiskSpaceUsage returns the total disk space used by the database in bytes,
// including live and obsolete files.
func (m *Metrics) DiskSpaceUsage() uint64 {
var usageBytes uint64
usageBytes += m.WAL.PhysicalSize
usageBytes += m.WAL.ObsoletePhysicalSize
for _, lm := range m.Levels {
usageBytes += uint64(lm.Size)
}
usageBytes += m.Table.ObsoleteSize
usageBytes += m.Table.ZombieSize
usageBytes += m.private.optionsFileSize
usageBytes += m.private.manifestFileSize
usageBytes += uint64(m.Compact.InProgressBytes)
return usageBytes
}
// NumVirtual is the number of virtual sstables in the latest version
// summed over every level in the lsm.
func (m *Metrics) NumVirtual() uint64 {
var n uint64
for _, level := range m.Levels {
n += level.NumVirtualFiles
}
return n
}
// VirtualSize is the sum of the sizes of the virtual sstables in the
// latest version. BackingTableSize - VirtualSize gives an estimate for
// the space amplification caused by not compacting virtual sstables.
func (m *Metrics) VirtualSize() uint64 {
var size uint64
for _, level := range m.Levels {
size += level.VirtualSize
}
return size
}
// ReadAmp returns the current read amplification of the database.
// It's computed as the number of sublevels in L0 + the number of non-empty
// levels below L0.
func (m *Metrics) ReadAmp() int {
var ramp int32
for _, l := range m.Levels {
ramp += l.Sublevels
}
return int(ramp)
}
// Total returns the sum of the per-level metrics and WAL metrics.
func (m *Metrics) Total() LevelMetrics {
var total LevelMetrics
for level := 0; level < numLevels; level++ {
l := &m.Levels[level]
total.Add(l)
total.Sublevels += l.Sublevels
}
// Compute total bytes-in as the bytes written to the WAL + bytes ingested.
total.BytesIn = m.WAL.BytesWritten + total.BytesIngested
// Add the total bytes-in to the total bytes-flushed. This is to account for
// the bytes written to the log and bytes written externally and then
// ingested.
total.BytesFlushed += total.BytesIn
return total
}
// String pretty-prints the metrics as below:
//
// | | | | ingested | moved | written | | amp
// level | tables size val-bl vtables | score | in | tables size | tables size | tables size | read | r w
// ------+-----------------------------+-------+-------+--------------+--------------+--------------+-------+---------
// 0 | 101 102B 0B 0 | 103.0 | 104B | 112 104B | 113 106B | 221 217B | 107B | 1 2.1
// 1 | 201 202B 0B 0 | 203.0 | 204B | 212 204B | 213 206B | 421 417B | 207B | 2 2.0
// 2 | 301 302B 0B 0 | 303.0 | 304B | 312 304B | 313 306B | 621 617B | 307B | 3 2.0
// 3 | 401 402B 0B 0 | 403.0 | 404B | 412 404B | 413 406B | 821 817B | 407B | 4 2.0
// 4 | 501 502B 0B 0 | 503.0 | 504B | 512 504B | 513 506B | 1.0K 1017B | 507B | 5 2.0
// 5 | 601 602B 0B 0 | 603.0 | 604B | 612 604B | 613 606B | 1.2K 1.2KB | 607B | 6 2.0
// 6 | 701 702B 0B 0 | - | 704B | 712 704B | 713 706B | 1.4K 1.4KB | 707B | 7 2.0
// total | 2.8K 2.7KB 0B 0 | - | 2.8KB | 2.9K 2.8KB | 2.9K 2.8KB | 5.7K 8.4KB | 2.8KB | 28 3.0
// -------------------------------------------------------------------------------------------------------------------
// WAL: 22 files (24B) in: 25B written: 26B (4% overhead)
// Flushes: 8
// Compactions: 5 estimated debt: 6B in progress: 2 (7B)
// default: 27 delete: 28 elision: 29 move: 30 read: 31 rewrite: 32 multi-level: 33
// MemTables: 12 (11B) zombie: 14 (13B)
// Zombie tables: 16 (15B)
// Backing tables: 0 (0B)
// Block cache: 2 entries (1B) hit rate: 42.9%
// Table cache: 18 entries (17B) hit rate: 48.7%
// Secondary cache: 40 entries (40B) hit rate: 49.9%
// Snapshots: 4 earliest seq num: 1024
// Table iters: 21
// Filter utility: 47.4%
// Ingestions: 27 as flushable: 36 (34B in 35 tables)
func (m *Metrics) String() string {
return redact.StringWithoutMarkers(m)
}
var _ redact.SafeFormatter = &Metrics{}
// SafeFormat implements redact.SafeFormatter.
func (m *Metrics) SafeFormat(w redact.SafePrinter, _ rune) {
// NB: Pebble does not make any assumptions as to which Go primitive types
// have been registered as safe with redact.RegisterSafeType and does not
// register any types itself. Some of the calls to `redact.Safe`, etc are
// superfluous in the context of CockroachDB, which registers all the Go
// numeric types as safe.
// TODO(jackson): There are a few places where we use redact.SafeValue
// instead of redact.RedactableString. This is necessary because of a bug
// whereby formatting a redact.RedactableString argument does not respect
// width specifiers. When the issue is fixed, we can convert these to
// RedactableStrings. https://github.com/cockroachdb/redact/issues/17
multiExists := m.Compact.MultiLevelCount > 0
appendIfMulti := func(line redact.SafeString) {
if multiExists {
w.SafeString(line)
}
}
newline := func() {
w.SafeString("\n")
}
w.SafeString(" | | | | ingested | moved | written | | amp")
appendIfMulti(" | multilevel")
newline()
w.SafeString("level | tables size val-bl vtables | score | in | tables size | tables size | tables size | read | r w")
appendIfMulti(" | top in read")
newline()
w.SafeString("------+-----------------------------+-------+-------+--------------+--------------+--------------+-------+---------")
appendIfMulti("-+------------------")
newline()
// formatRow prints out a row of the table.
formatRow := func(m *LevelMetrics, score float64) {
scoreStr := "-"
if !math.IsNaN(score) {
// Try to keep the string no longer than 5 characters.
switch {
case score < 99.995:
scoreStr = fmt.Sprintf("%.2f", score)
case score < 999.95:
scoreStr = fmt.Sprintf("%.1f", score)
default:
scoreStr = fmt.Sprintf("%.0f", score)
}
}
var wampStr string
if wamp := m.WriteAmp(); wamp > 99.5 {
wampStr = fmt.Sprintf("%.0f", wamp)
} else {
wampStr = fmt.Sprintf("%.1f", wamp)
}
w.Printf("| %5s %6s %6s %7s | %5s | %5s | %5s %6s | %5s %6s | %5s %6s | %5s | %3d %4s",
humanize.Count.Int64(m.NumFiles),
humanize.Bytes.Int64(m.Size),
humanize.Bytes.Uint64(m.Additional.ValueBlocksSize),
humanize.Count.Uint64(m.NumVirtualFiles),
redact.Safe(scoreStr),
humanize.Bytes.Uint64(m.BytesIn),
humanize.Count.Uint64(m.TablesIngested),
humanize.Bytes.Uint64(m.BytesIngested),
humanize.Count.Uint64(m.TablesMoved),
humanize.Bytes.Uint64(m.BytesMoved),
humanize.Count.Uint64(m.TablesFlushed+m.TablesCompacted),
humanize.Bytes.Uint64(m.BytesFlushed+m.BytesCompacted),
humanize.Bytes.Uint64(m.BytesRead),
redact.Safe(m.Sublevels),
redact.Safe(wampStr))
if multiExists {
w.Printf(" | %5s %5s %5s",
humanize.Bytes.Uint64(m.MultiLevel.BytesInTop),
humanize.Bytes.Uint64(m.MultiLevel.BytesIn),
humanize.Bytes.Uint64(m.MultiLevel.BytesRead))
}
newline()
}
var total LevelMetrics
for level := 0; level < numLevels; level++ {
l := &m.Levels[level]
w.Printf("%5d ", redact.Safe(level))
// Format the score.
score := math.NaN()
if level < numLevels-1 {
score = l.Score
}
formatRow(l, score)
total.Add(l)
total.Sublevels += l.Sublevels
}
// Compute total bytes-in as the bytes written to the WAL + bytes ingested.
total.BytesIn = m.WAL.BytesWritten + total.BytesIngested
// Add the total bytes-in to the total bytes-flushed. This is to account for
// the bytes written to the log and bytes written externally and then
// ingested.
total.BytesFlushed += total.BytesIn
w.SafeString("total ")
formatRow(&total, math.NaN())
w.SafeString("-------------------------------------------------------------------------------------------------------------------")
appendIfMulti("--------------------")
newline()
w.Printf("WAL: %d files (%s) in: %s written: %s (%.0f%% overhead)\n",
redact.Safe(m.WAL.Files),
humanize.Bytes.Uint64(m.WAL.Size),
humanize.Bytes.Uint64(m.WAL.BytesIn),
humanize.Bytes.Uint64(m.WAL.BytesWritten),
redact.Safe(percent(int64(m.WAL.BytesWritten)-int64(m.WAL.BytesIn), int64(m.WAL.BytesIn))))
w.Printf("Flushes: %d\n", redact.Safe(m.Flush.Count))
w.Printf("Compactions: %d estimated debt: %s in progress: %d (%s)\n",
redact.Safe(m.Compact.Count),
humanize.Bytes.Uint64(m.Compact.EstimatedDebt),
redact.Safe(m.Compact.NumInProgress),
humanize.Bytes.Int64(m.Compact.InProgressBytes))
w.Printf(" default: %d delete: %d elision: %d move: %d read: %d rewrite: %d multi-level: %d\n",
redact.Safe(m.Compact.DefaultCount),
redact.Safe(m.Compact.DeleteOnlyCount),
redact.Safe(m.Compact.ElisionOnlyCount),
redact.Safe(m.Compact.MoveCount),
redact.Safe(m.Compact.ReadCount),
redact.Safe(m.Compact.RewriteCount),
redact.Safe(m.Compact.MultiLevelCount))
w.Printf("MemTables: %d (%s) zombie: %d (%s)\n",
redact.Safe(m.MemTable.Count),
humanize.Bytes.Uint64(m.MemTable.Size),
redact.Safe(m.MemTable.ZombieCount),
humanize.Bytes.Uint64(m.MemTable.ZombieSize))
w.Printf("Zombie tables: %d (%s)\n",
redact.Safe(m.Table.ZombieCount),
humanize.Bytes.Uint64(m.Table.ZombieSize))
w.Printf("Backing tables: %d (%s)\n",
redact.Safe(m.Table.BackingTableCount),
humanize.Bytes.Uint64(m.Table.BackingTableSize))
w.Printf("Virtual tables: %d (%s)\n",
redact.Safe(m.NumVirtual()),
humanize.Bytes.Uint64(m.VirtualSize()))
formatCacheMetrics := func(m *CacheMetrics, name redact.SafeString) {
w.Printf("%s: %s entries (%s) hit rate: %.1f%%\n",
name,
humanize.Count.Int64(m.Count),
humanize.Bytes.Int64(m.Size),
redact.Safe(hitRate(m.Hits, m.Misses)))
}
formatCacheMetrics(&m.BlockCache, "Block cache")
formatCacheMetrics(&m.TableCache, "Table cache")
formatSharedCacheMetrics := func(w redact.SafePrinter, m *SecondaryCacheMetrics, name redact.SafeString) {
w.Printf("%s: %s entries (%s) hit rate: %.1f%%\n",
name,
humanize.Count.Int64(m.Count),
humanize.Bytes.Int64(m.Size),
redact.Safe(hitRate(m.ReadsWithFullHit, m.ReadsWithPartialHit+m.ReadsWithNoHit)))
}
formatSharedCacheMetrics(w, &m.SecondaryCacheMetrics, "Secondary cache")
w.Printf("Snapshots: %d earliest seq num: %d\n",
redact.Safe(m.Snapshots.Count),
redact.Safe(m.Snapshots.EarliestSeqNum))
w.Printf("Table iters: %d\n", redact.Safe(m.TableIters))
w.Printf("Filter utility: %.1f%%\n", redact.Safe(hitRate(m.Filter.Hits, m.Filter.Misses)))
w.Printf("Ingestions: %d as flushable: %d (%s in %d tables)\n",
redact.Safe(m.Ingest.Count),
redact.Safe(m.Flush.AsIngestCount),
humanize.Bytes.Uint64(m.Flush.AsIngestBytes),
redact.Safe(m.Flush.AsIngestTableCount))
}
func hitRate(hits, misses int64) float64 {
return percent(hits, hits+misses)
}
func percent(numerator, denominator int64) float64 {
if denominator == 0 {
return 0
}
return 100 * float64(numerator) / float64(denominator)
}
// StringForTests is identical to m.String() on 64-bit platforms. It is used to
// provide a platform-independent result for tests.
func (m *Metrics) StringForTests() string {
mCopy := *m
if math.MaxInt == math.MaxInt32 {
// This is the difference in Sizeof(sstable.Reader{})) between 64 and 32 bit
// platforms.
const tableCacheSizeAdjustment = 212
mCopy.TableCache.Size += mCopy.TableCache.Count * tableCacheSizeAdjustment
}
return redact.StringWithoutMarkers(&mCopy)
}