Files
tidb/pkg/ddl/session/session_pool.go

102 lines
2.9 KiB
Go

// Copyright 2023 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 session
import (
"context"
"fmt"
"sync"
"github.com/ngaut/pools"
"github.com/pingcap/errors"
"github.com/pingcap/kvproto/pkg/kvrpcpb"
"github.com/pingcap/tidb/pkg/ddl/logutil"
"github.com/pingcap/tidb/pkg/domain/infosync"
"github.com/pingcap/tidb/pkg/parser/mysql"
"github.com/pingcap/tidb/pkg/sessionctx"
"github.com/pingcap/tidb/pkg/util"
"github.com/pingcap/tidb/pkg/util/intest"
)
// Pool is used to new Session.
type Pool struct {
mu struct {
sync.Mutex
closed bool
}
resPool util.SessionPool
}
// NewSessionPool creates a new Session pool.
func NewSessionPool(resPool util.SessionPool) *Pool {
intest.AssertNotNil(resPool)
return &Pool{resPool: resPool}
}
// Get gets sessionCtx from context resource pool.
// Please remember to call Put after you finished using sessionCtx.
func (sg *Pool) Get() (sessionctx.Context, error) {
sg.mu.Lock()
if sg.mu.closed {
sg.mu.Unlock()
return nil, errors.Errorf("session pool is closed")
}
sg.mu.Unlock()
// no need to protect sg.resPool
resource, err := sg.resPool.Get()
if err != nil {
return nil, errors.Trace(err)
}
ctx, ok := resource.(sessionctx.Context)
if !ok {
return nil, errors.Trace(fmt.Errorf("need sessionctx.Context, but got %T", ctx))
}
ctx.GetSessionVars().SetStatusFlag(mysql.ServerStatusAutocommit, true)
ctx.GetSessionVars().InRestrictedSQL = true
ctx.GetSessionVars().StmtCtx.SetTimeZone(ctx.GetSessionVars().Location())
ctx.GetSessionVars().SetDiskFullOpt(kvrpcpb.DiskFullOpt_AllowedOnAlmostFull)
infosync.StoreInternalSession(ctx)
return ctx, nil
}
// Put returns sessionCtx to context resource pool.
func (sg *Pool) Put(ctx sessionctx.Context) {
// no need to protect sg.resPool, even the sg.resPool is closed, the ctx still need to
// Put into resPool, because when resPool is closing, it will wait all the ctx returns, then resPool finish closing.
intest.AssertFunc(func() bool {
txn, _ := ctx.Txn(false)
return txn == nil || !txn.Valid()
})
ctx.RollbackTxn(context.Background())
ctx.GetSessionVars().ClearDiskFullOpt()
sg.resPool.Put(ctx.(pools.Resource))
infosync.DeleteInternalSession(ctx)
}
// Close clean up the Pool.
func (sg *Pool) Close() {
sg.mu.Lock()
defer sg.mu.Unlock()
// prevent closing resPool twice.
if sg.mu.closed {
return
}
logutil.DDLLogger().Info("closing session pool")
sg.resPool.Close()
sg.mu.closed = true
}