tidb infoschema 源码
tidb infoschema 代码
文件路径：/table/temptable/infoschema.go
// Copyright 2021 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 temptable
import (
"github.com/pingcap/tidb/infoschema"
"github.com/pingcap/tidb/sessionctx"
)
// AttachLocalTemporaryTableInfoSchema attach local temporary table information schema to is
func AttachLocalTemporaryTableInfoSchema(sctx sessionctx.Context, is infoschema.InfoSchema) infoschema.InfoSchema {
localTemporaryTables := getLocalTemporaryTables(sctx)
if localTemporaryTables == nil {
return is
}
if se, ok := is.(*infoschema.SessionExtendedInfoSchema); ok {
se.LocalTemporaryTables = localTemporaryTables
return is
}
return &infoschema.SessionExtendedInfoSchema{
InfoSchema: is,
LocalTemporaryTables: localTemporaryTables,
}
}
// DetachLocalTemporaryTableInfoSchema detach local temporary table information schema from is
func DetachLocalTemporaryTableInfoSchema(is infoschema.InfoSchema) infoschema.InfoSchema {
if attachedInfoSchema, ok := is.(*infoschema.SessionExtendedInfoSchema); ok {
newIs := *attachedInfoSchema
newIs.LocalTemporaryTables = nil
return &newIs
}
return is
}
func getLocalTemporaryTables(sctx sessionctx.Context) *infoschema.SessionTables {
localTemporaryTables := sctx.GetSessionVars().LocalTemporaryTables
if localTemporaryTables == nil {
return nil
}
return localTemporaryTables.(*infoschema.SessionTables)
}
func ensureLocalTemporaryTables(sctx sessionctx.Context) *infoschema.SessionTables {
sessVars := sctx.GetSessionVars()
if sessVars.LocalTemporaryTables == nil {
localTempTables := infoschema.NewSessionTables()
sessVars.LocalTemporaryTables = localTempTables
return localTempTables
}
return sessVars.LocalTemporaryTables.(*infoschema.SessionTables)
}
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