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gitea/vendor/github.com/pingcap/tidb/perfschema/instrument.go

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// Copyright 2016 PingCAP, Inc.
//
// 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,
// See the License for the specific language governing permissions and
// limitations under the License.
package perfschema
import (
"fmt"
"github.com/juju/errors"
"github.com/pingcap/tidb/mysql"
"github.com/pingcap/tidb/util/types"
)
// EnumCallerName is used as a parameter to avoid calling runtime.Caller(1) since
// it is too expensive (500ns+ per call), we don't want to invoke it repeatedly for
// each instrument.
type EnumCallerName int
const (
// CallerNameSessionExecute is for session.go:Execute() method.
CallerNameSessionExecute EnumCallerName = iota + 1
)
const (
stageInstrumentPrefix = "stage/"
statementInstrumentPrefix = "statement/"
transactionInstrumentPrefix = "transaction"
)
// Flag indicators for table setup_timers.
const (
flagStage = iota + 1
flagStatement
flagTransaction
)
type enumTimerName int
// Enum values for the TIMER_NAME columns.
// This enum is found in the following tables:
// - performance_schema.setup_timer (TIMER_NAME)
const (
timerNameNone enumTimerName = iota
timerNameNanosec
timerNameMicrosec
timerNameMillisec
)
var (
callerNames = make(map[EnumCallerName]string)
)
// addInstrument is used to add an item to setup_instruments table.
func (ps *perfSchema) addInstrument(name string) (uint64, error) {
record := types.MakeDatums(name, mysql.Enum{Name: "YES", Value: 1}, mysql.Enum{Name: "YES", Value: 1})
tbl := ps.mTables[TableSetupInstruments]
handle, err := tbl.AddRecord(nil, record)
return uint64(handle), errors.Trace(err)
}
func (ps *perfSchema) getTimerName(flag int) (enumTimerName, error) {
if flag < 0 || flag >= len(setupTimersRecords) {
return timerNameNone, errors.Errorf("Unknown timerName flag %d", flag)
}
timerName := fmt.Sprintf("%s", setupTimersRecords[flag][1].GetString())
switch timerName {
case "NANOSECOND":
return timerNameNanosec, nil
case "MICROSECOND":
return timerNameMicrosec, nil
case "MILLISECOND":
return timerNameMillisec, nil
}
return timerNameNone, nil
}