Files
tidb/pkg/sessionctx/vardef/runtime.go

78 lines
2.7 KiB
Go

// Copyright 2025 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 vardef
import (
"strings"
"sync/atomic"
"time"
)
var (
// schemaLease is lease of info schema, we use this to check whether info schema
// is valid in SchemaChecker. we also use half of it as info schema reload interval.
// Default info schema lease 45s which is init at main, we set it to 1 second
// here for tests. you can change it with a proper time, but you must know that
// too little may cause badly performance degradation.
schemaLease = int64(1 * time.Second)
// statsLease is the time for reload stats table.
statsLease = int64(3 * time.Second)
// planReplayerGCLease is the time for plan replayer gc.
planReplayerGCLease = int64(10 * time.Minute)
)
// SetSchemaLease changes the default schema lease time for DDL.
// This function is very dangerous, don't use it if you really know what you do.
// SetSchemaLease only affects not local storage after bootstrapped.
func SetSchemaLease(lease time.Duration) {
atomic.StoreInt64(&schemaLease, int64(lease))
}
// GetSchemaLease returns the schema lease time.
func GetSchemaLease() time.Duration {
return time.Duration(atomic.LoadInt64(&schemaLease))
}
// SetStatsLease changes the default stats lease time for loading stats info.
func SetStatsLease(lease time.Duration) {
atomic.StoreInt64(&statsLease, int64(lease))
}
// GetStatsLease returns the stats lease time.
func GetStatsLease() time.Duration {
return time.Duration(atomic.LoadInt64(&statsLease))
}
// SetPlanReplayerGCLease changes the default plan repalyer gc lease time.
func SetPlanReplayerGCLease(lease time.Duration) {
atomic.StoreInt64(&planReplayerGCLease, int64(lease))
}
// GetPlanReplayerGCLease returns the plan replayer gc lease time.
func GetPlanReplayerGCLease() time.Duration {
return time.Duration(atomic.LoadInt64(&planReplayerGCLease))
}
// IsReadOnlyVarInNextGen checks if the variable is read-only in the nextgen.
func IsReadOnlyVarInNextGen(name string) bool {
name = strings.ToLower(name)
switch name {
case TiDBEnableMDL, TiDBMaxDistTaskNodes, TiDBDDLReorgMaxWriteSpeed, TiDBDDLDiskQuota,
TiDBEnableDistTask, TiDBDDLEnableFastReorg:
return true
}
return false
}