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logstats: do not allocate memory while logging (vitessio#15539)
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Signed-off-by: Vicent Marti <vmg@strn.cat>
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vmg authored and arthurschreiber committed Oct 17, 2024
1 parent 03bf1e5 commit 3cfefd4
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Showing 7 changed files with 343 additions and 131 deletions.
217 changes: 217 additions & 0 deletions go/logstats/logger.go
Original file line number Diff line number Diff line change
@@ -0,0 +1,217 @@
/*
Copyright 2024 The Vitess Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package logstats

import (
"io"
"slices"
"strconv"
"strings"
"sync"
"time"

"vitess.io/vitess/go/hack"
"vitess.io/vitess/go/sqltypes"
querypb "vitess.io/vitess/go/vt/proto/query"
)

type logbv struct {
Name string
BVar *querypb.BindVariable
}

// Logger is a zero-allocation logger for logstats.
// It can output logs as JSON or as plaintext, following the commonly used
// logstats format that is shared between the tablets and the gates.
type Logger struct {
b []byte
bvars []logbv
n int
json bool
}

func sortBVars(sorted []logbv, bvars map[string]*querypb.BindVariable) []logbv {
for k, bv := range bvars {
sorted = append(sorted, logbv{k, bv})
}
slices.SortFunc(sorted, func(a, b logbv) int {
return strings.Compare(a.Name, b.Name)
})
return sorted
}

func (log *Logger) appendBVarsJSON(b []byte, bvars map[string]*querypb.BindVariable, full bool) []byte {
log.bvars = sortBVars(log.bvars[:0], bvars)

b = append(b, '{')
for i, bv := range log.bvars {
if i > 0 {
b = append(b, ',', ' ')
}
b = strconv.AppendQuote(b, bv.Name)
b = append(b, `: {"type": `...)
b = strconv.AppendQuote(b, querypb.Type_name[int32(bv.BVar.Type)])
b = append(b, `, "value": `...)

if sqltypes.IsIntegral(bv.BVar.Type) || sqltypes.IsFloat(bv.BVar.Type) {
b = append(b, bv.BVar.Value...)
} else if bv.BVar.Type == sqltypes.Tuple {
b = append(b, '"')
b = strconv.AppendInt(b, int64(len(bv.BVar.Values)), 10)
b = append(b, ` items"`...)
} else {
if full {
b = strconv.AppendQuote(b, hack.String(bv.BVar.Value))
} else {
b = append(b, '"')
b = strconv.AppendInt(b, int64(len(bv.BVar.Values)), 10)
b = append(b, ` bytes"`...)
}
}
b = append(b, '}')
}
return append(b, '}')
}

func (log *Logger) Init(json bool) {
log.n = 0
log.json = json
if log.json {
log.b = append(log.b, '{')
}
}

func (log *Logger) Redacted() {
log.String("[REDACTED]")
}

func (log *Logger) Key(key string) {
if log.json {
if log.n > 0 {
log.b = append(log.b, ',', ' ')
}
log.b = append(log.b, '"')
log.b = append(log.b, key...)
log.b = append(log.b, '"', ':', ' ')
} else {
if log.n > 0 {
log.b = append(log.b, '\t')
}
}
log.n++
}

func (log *Logger) StringUnquoted(value string) {
if log.json {
log.b = strconv.AppendQuote(log.b, value)
} else {
log.b = append(log.b, value...)
}
}

func (log *Logger) TabTerminated() {
if !log.json {
log.b = append(log.b, '\t')
}
}

func (log *Logger) String(value string) {
log.b = strconv.AppendQuote(log.b, value)
}

func (log *Logger) StringSingleQuoted(value string) {
if log.json {
log.b = strconv.AppendQuote(log.b, value)
} else {
log.b = append(log.b, '\'')
log.b = append(log.b, value...)
log.b = append(log.b, '\'')
}
}

func (log *Logger) Time(t time.Time) {
const timeFormat = "2006-01-02 15:04:05.000000"
if log.json {
log.b = append(log.b, '"')
log.b = t.AppendFormat(log.b, timeFormat)
log.b = append(log.b, '"')
} else {
log.b = t.AppendFormat(log.b, timeFormat)
}
}

func (log *Logger) Duration(t time.Duration) {
log.b = strconv.AppendFloat(log.b, t.Seconds(), 'f', 6, 64)
}

func (log *Logger) BindVariables(bvars map[string]*querypb.BindVariable, full bool) {
// the bind variables are printed as JSON in text mode because the original
// printing syntax, which was simply `fmt.Sprintf("%v")`, is not stable or
// safe to parse
log.b = log.appendBVarsJSON(log.b, bvars, full)
}

func (log *Logger) Int(i int64) {
log.b = strconv.AppendInt(log.b, i, 10)
}

func (log *Logger) Uint(u uint64) {
log.b = strconv.AppendUint(log.b, u, 10)
}

func (log *Logger) Bool(b bool) {
log.b = strconv.AppendBool(log.b, b)
}

func (log *Logger) Strings(strs []string) {
log.b = append(log.b, '[')
for i, t := range strs {
if i > 0 {
log.b = append(log.b, ',')
}
log.b = strconv.AppendQuote(log.b, t)
}
log.b = append(log.b, ']')
}

func (log *Logger) Flush(w io.Writer) (err error) {
if log.json {
log.b = append(log.b, '}')
}
log.b = append(log.b, '\n')
_, err = w.Write(log.b)

clear(log.bvars)
log.bvars = log.bvars[:0]
log.b = log.b[:0]
log.n = 0

loggerPool.Put(log)
return err
}

var loggerPool = sync.Pool{New: func() any {
return &Logger{}
}}

// NewLogger returns a new Logger instance to perform logstats logging.
// The logger must be initialized with (*Logger).Init before usage and
// flushed with (*Logger).Flush once all the key-values have been written
// to it.
func NewLogger() *Logger {
return loggerPool.Get().(*Logger)
}
122 changes: 54 additions & 68 deletions go/vt/vtgate/logstats/logstats.go
Original file line number Diff line number Diff line change
Expand Up @@ -18,21 +18,16 @@ package logstats

import (
"context"
"encoding/json"
"fmt"
"io"
"net/url"
"time"

"github.com/google/safehtml"

"vitess.io/vitess/go/sqltypes"
"vitess.io/vitess/go/logstats"
"vitess.io/vitess/go/streamlog"
"vitess.io/vitess/go/tb"
"vitess.io/vitess/go/vt/callerid"
"vitess.io/vitess/go/vt/callinfo"
"vitess.io/vitess/go/vt/log"

querypb "vitess.io/vitess/go/vt/proto/query"
)

Expand Down Expand Up @@ -128,69 +123,60 @@ func (stats *LogStats) Logf(w io.Writer, params url.Values) error {
return nil
}

// FormatBindVariables call might panic so we're going to catch it here
// and print out the stack trace for debugging.
defer func() {
if x := recover(); x != nil {
log.Errorf("Uncaught panic:\n%v\n%s", x, tb.Stack(4))
}
}()

formattedBindVars := "\"[REDACTED]\""
if !streamlog.GetRedactDebugUIQueries() {
_, fullBindParams := params["full"]
formattedBindVars = sqltypes.FormatBindVariables(
stats.BindVariables,
fullBindParams,
streamlog.GetQueryLogFormat() == streamlog.QueryLogFormatJSON,
)
}

// TODO: remove username here we fully enforce immediate caller id
redacted := streamlog.GetRedactDebugUIQueries()
_, fullBindParams := params["full"]
remoteAddr, username := stats.RemoteAddrUsername()

var fmtString string
switch streamlog.GetQueryLogFormat() {
case streamlog.QueryLogFormatText:
fmtString = "%v\t%v\t%v\t'%v'\t'%v'\t%v\t%v\t%.6f\t%.6f\t%.6f\t%.6f\t%v\t%q\t%v\t%v\t%v\t%q\t%q\t%q\t%v\t%v\t%q\n"
case streamlog.QueryLogFormatJSON:
fmtString = "{\"Method\": %q, \"RemoteAddr\": %q, \"Username\": %q, \"ImmediateCaller\": %q, \"Effective Caller\": %q, \"Start\": \"%v\", \"End\": \"%v\", \"TotalTime\": %.6f, \"PlanTime\": %v, \"ExecuteTime\": %v, \"CommitTime\": %v, \"StmtType\": %q, \"SQL\": %q, \"BindVars\": %v, \"ShardQueries\": %v, \"RowsAffected\": %v, \"Error\": %q, \"TabletType\": %q, \"SessionUUID\": %q, \"Cached Plan\": %v, \"TablesUsed\": %v, \"ActiveKeyspace\": %q}\n"
}

tables := stats.TablesUsed
if tables == nil {
tables = []string{}
}
tablesUsed, marshalErr := json.Marshal(tables)
if marshalErr != nil {
return marshalErr
log := logstats.NewLogger()
log.Init(streamlog.GetQueryLogFormat() == streamlog.QueryLogFormatJSON)
log.Key("Method")
log.StringUnquoted(stats.Method)
log.Key("RemoteAddr")
log.StringUnquoted(remoteAddr)
log.Key("Username")
log.StringUnquoted(username)
log.Key("ImmediateCaller")
log.StringSingleQuoted(stats.ImmediateCaller())
log.Key("Effective Caller")
log.StringSingleQuoted(stats.EffectiveCaller())
log.Key("Start")
log.Time(stats.StartTime)
log.Key("End")
log.Time(stats.EndTime)
log.Key("TotalTime")
log.Duration(stats.TotalTime())
log.Key("PlanTime")
log.Duration(stats.PlanTime)
log.Key("ExecuteTime")
log.Duration(stats.ExecuteTime)
log.Key("CommitTime")
log.Duration(stats.CommitTime)
log.Key("StmtType")
log.StringUnquoted(stats.StmtType)
log.Key("SQL")
log.String(stats.SQL)
log.Key("BindVars")
if redacted {
log.Redacted()
} else {
log.BindVariables(stats.BindVariables, fullBindParams)
}
_, err := fmt.Fprintf(
w,
fmtString,
stats.Method,
remoteAddr,
username,
stats.ImmediateCaller(),
stats.EffectiveCaller(),
stats.StartTime.Format("2006-01-02 15:04:05.000000"),
stats.EndTime.Format("2006-01-02 15:04:05.000000"),
stats.TotalTime().Seconds(),
stats.PlanTime.Seconds(),
stats.ExecuteTime.Seconds(),
stats.CommitTime.Seconds(),
stats.StmtType,
stats.SQL,
formattedBindVars,
stats.ShardQueries,
stats.RowsAffected,
stats.ErrorStr(),
stats.TabletType,
stats.SessionUUID,
stats.CachedPlan,
string(tablesUsed),
stats.ActiveKeyspace,
)

return err
log.Key("ShardQueries")
log.Uint(stats.ShardQueries)
log.Key("RowsAffected")
log.Uint(stats.RowsAffected)
log.Key("Error")
log.String(stats.ErrorStr())
log.Key("TabletType")
log.String(stats.TabletType)
log.Key("SessionUUID")
log.String(stats.SessionUUID)
log.Key("Cached Plan")
log.Bool(stats.CachedPlan)
log.Key("TablesUsed")
log.Strings(stats.TablesUsed)
log.Key("ActiveKeyspace")
log.String(stats.ActiveKeyspace)

return log.Flush(w)
}
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