tidb load_stats 源码
tidb load_stats 代码
文件路径：/executor/load_stats.go
// Copyright 2018 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,
// 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 executor
import (
"context"
"encoding/json"
"github.com/pingcap/errors"
"github.com/pingcap/tidb/domain"
"github.com/pingcap/tidb/infoschema"
"github.com/pingcap/tidb/sessionctx"
"github.com/pingcap/tidb/statistics/handle"
"github.com/pingcap/tidb/util/chunk"
)
var _ Executor = &LoadStatsExec{}
// LoadStatsExec represents a load statistic executor.
type LoadStatsExec struct {
baseExecutor
info *LoadStatsInfo
}
// LoadStatsInfo saves the information of loading statistic operation.
type LoadStatsInfo struct {
Path string
Ctx sessionctx.Context
}
// loadStatsVarKeyType is a dummy type to avoid naming collision in context.
type loadStatsVarKeyType int
// String defines a Stringer function for debugging and pretty printing.
func (k loadStatsVarKeyType) String() string {
return "load_stats_var"
}
// LoadStatsVarKey is a variable key for load statistic.
const LoadStatsVarKey loadStatsVarKeyType = 0
// Next implements the Executor Next interface.
func (e *LoadStatsExec) Next(ctx context.Context, req *chunk.Chunk) error {
req.GrowAndReset(e.maxChunkSize)
if len(e.info.Path) == 0 {
return errors.New("Load Stats: file path is empty")
}
val := e.ctx.Value(LoadStatsVarKey)
if val != nil {
e.ctx.SetValue(LoadStatsVarKey, nil)
return errors.New("Load Stats: previous load stats option isn't closed normally")
}
e.ctx.SetValue(LoadStatsVarKey, e.info)
return nil
}
// Close implements the Executor Close interface.
func (e *LoadStatsExec) Close() error {
return nil
}
// Open implements the Executor Open interface.
func (e *LoadStatsExec) Open(ctx context.Context) error {
return nil
}
// Update updates the stats of the corresponding table according to the data.
func (e *LoadStatsInfo) Update(data []byte) error {
jsonTbl := &handle.JSONTable{}
if err := json.Unmarshal(data, jsonTbl); err != nil {
return errors.Trace(err)
}
do := domain.GetDomain(e.Ctx)
h := do.StatsHandle()
if h == nil {
return errors.New("Load Stats: handle is nil")
}
return h.LoadStatsFromJSON(e.Ctx.GetInfoSchema().(infoschema.InfoSchema), jsonTbl)
}
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