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gitea/vendor/github.com/pingcap/tidb/perfschema/perfschema.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 (
"github.com/pingcap/tidb/kv"
"github.com/pingcap/tidb/model"
"github.com/pingcap/tidb/table"
)
// StatementInstrument defines the methods for statement instrumentation points
type StatementInstrument interface {
RegisterStatement(category, name string, elem interface{})
StartStatement(sql string, connID uint64, callerName EnumCallerName, elem interface{}) *StatementState
EndStatement(state *StatementState)
}
// PerfSchema defines the methods to be invoked by the executor
type PerfSchema interface {
// For statement instrumentation only.
StatementInstrument
// GetDBMeta returns db info for PerformanceSchema.
GetDBMeta() *model.DBInfo
// GetTable returns table instance for name.
GetTable(name string) (table.Table, bool)
}
type perfSchema struct {
store kv.Storage
dbInfo *model.DBInfo
tables map[string]*model.TableInfo
mTables map[string]table.Table // MemoryTables for perfSchema
// Used for TableStmtsHistory
historyHandles []int64
historyCursor int
}
var _ PerfSchema = (*perfSchema)(nil)
// PerfHandle is the only access point for the in-memory performance schema information
var (
PerfHandle PerfSchema
)
// NewPerfHandle creates a new perfSchema on store.
func NewPerfHandle(store kv.Storage) PerfSchema {
schema := PerfHandle.(*perfSchema)
schema.store = store
schema.historyHandles = make([]int64, 0, stmtsHistoryElemMax)
_ = schema.initialize()
registerStatements()
return PerfHandle
}
func init() {
schema := &perfSchema{}
PerfHandle = schema
}