91 lines
3.1 KiB
Go
91 lines
3.1 KiB
Go
// Copyright 2019 PingCAP, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package bindinfo
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import (
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"time"
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"github.com/pingcap/tidb/pkg/sessionctx/vardef"
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"github.com/pingcap/tidb/pkg/sessionctx/variable"
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"github.com/pingcap/tidb/pkg/util"
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)
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// Lease influences the duration of loading bind info and handling invalid bind.
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var Lease = 3 * time.Second
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const (
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// OwnerKey is the bindinfo owner path that is saved to etcd.
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OwnerKey = "/tidb/bindinfo/owner"
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// Prompt is the prompt for bindinfo owner manager.
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Prompt = "bindinfo"
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// BuiltinPseudoSQL4BindLock is used to simulate LOCK TABLE for mysql.bind_info.
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BuiltinPseudoSQL4BindLock = "builtin_pseudo_sql_for_bind_lock"
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// LockBindInfoSQL simulates LOCK TABLE by updating a same row in each pessimistic transaction.
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LockBindInfoSQL = `UPDATE mysql.bind_info SET source= 'builtin' WHERE original_sql= 'builtin_pseudo_sql_for_bind_lock'`
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// StmtRemoveDuplicatedPseudoBinding is used to remove duplicated pseudo binding.
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// After using BR to sync bind_info between two clusters, the pseudo binding may be duplicated, and
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// BR use this statement to remove duplicated rows, and this SQL should only be executed by BR.
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StmtRemoveDuplicatedPseudoBinding = `DELETE FROM mysql.bind_info
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WHERE original_sql='builtin_pseudo_sql_for_bind_lock' AND
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_tidb_rowid NOT IN ( -- keep one arbitrary pseudo binding
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SELECT _tidb_rowid FROM mysql.bind_info WHERE original_sql='builtin_pseudo_sql_for_bind_lock' limit 1)`
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)
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// BindingHandle is used to handle all sql bind operations.
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type BindingHandle interface {
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BindingCacheUpdater
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BindingOperator
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BindingPlanEvolution
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variable.Statistics
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}
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// bindingHandle is used to handle all sql bind operations.
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type bindingHandle struct {
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BindingCacheUpdater
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BindingOperator
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BindingPlanEvolution
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}
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// NewBindingHandle creates a new BindingHandle.
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func NewBindingHandle(sPool util.DestroyableSessionPool) BindingHandle {
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cache := NewBindingCacheUpdater(sPool)
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op := newBindingOperator(sPool, cache)
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auto := newBindingAuto(sPool)
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h := &bindingHandle{BindingOperator: op, BindingCacheUpdater: cache, BindingPlanEvolution: auto}
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variable.RegisterStatistics(h)
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return h
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}
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var (
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lastPlanBindingUpdateTime = "last_plan_binding_update_time"
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)
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// GetScope gets the status variables scope.
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func (*bindingHandle) GetScope(_ string) vardef.ScopeFlag {
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return vardef.ScopeSession
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}
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// Stats returns the server statistics.
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func (h *bindingHandle) Stats(_ *variable.SessionVars) (map[string]any, error) {
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m := make(map[string]any)
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m[lastPlanBindingUpdateTime] = h.LastUpdateTime().String()
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return m, nil
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}
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