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// Copyright 2019 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,
// See the License for the specific language governing permissions and
// limitations under the License.
package bindinfo
import (
"time"
"github.com/pingcap/parser"
"github.com/pingcap/parser/mysql"
"github.com/pingcap/tidb/metrics"
"github.com/pingcap/tidb/sessionctx"
"github.com/pingcap/tidb/types"
)
// SessionHandle is used to handle all session sql bind operations.
type SessionHandle struct {
ch cache
parser *parser.Parser
}
// NewSessionBindHandle creates a new SessionBindHandle.
func NewSessionBindHandle(parser *parser.Parser) *SessionHandle {
sessionHandle := &SessionHandle{parser: parser}
sessionHandle.ch = make(cache)
return sessionHandle
}
// appendBindRecord adds the BindRecord to the cache, all the stale bindMetas are
// removed from the cache after this operation.
func (h *SessionHandle) appendBindRecord(hash string, meta *BindRecord) {
oldRecord := h.ch.getBindRecord(hash, meta.OriginalSQL, meta.Db)
h.ch.setBindRecord(hash, meta)
updateMetrics(metrics.ScopeSession, oldRecord, meta, false)
}
// CreateBindRecord creates a BindRecord to the cache.
// It replaces all the exists bindings for the same normalized SQL.
func (h *SessionHandle) CreateBindRecord(sctx sessionctx.Context, record *BindRecord) (err error) {
err = record.prepareHints(sctx)
if err != nil {
return err
}
now := types.NewTime(types.FromGoTime(time.Now().In(sctx.GetSessionVars().StmtCtx.TimeZone)), mysql.TypeTimestamp, 3)
for i := range record.Bindings {
record.Bindings[i].CreateTime = now
record.Bindings[i].UpdateTime = now
}
// update the BindMeta to the cache.
h.appendBindRecord(parser.DigestNormalized(record.OriginalSQL), record)
return nil
}
// DropBindRecord drops a BindRecord in the cache.
func (h *SessionHandle) DropBindRecord(originalSQL, db string, binding *Binding) error {
oldRecord := h.GetBindRecord(originalSQL, db)
var newRecord *BindRecord
record := &BindRecord{OriginalSQL: originalSQL, Db: db}
if binding != nil {
record.Bindings = append(record.Bindings, *binding)
}
if oldRecord != nil {
newRecord = oldRecord.remove(record)
} else {
newRecord = record
}
h.ch.setBindRecord(parser.DigestNormalized(record.OriginalSQL), newRecord)
updateMetrics(metrics.ScopeSession, oldRecord, newRecord, false)
return nil
}
// GetBindRecord return the BindMeta of the (normdOrigSQL,db) if BindMeta exist.
func (h *SessionHandle) GetBindRecord(normdOrigSQL, db string) *BindRecord {
hash := parser.DigestNormalized(normdOrigSQL)
bindRecords := h.ch[hash]
for _, bindRecord := range bindRecords {
if bindRecord.OriginalSQL == normdOrigSQL && bindRecord.Db == db {
return bindRecord
}
}
return nil
}
// GetAllBindRecord return all session bind info.
func (h *SessionHandle) GetAllBindRecord() (bindRecords []*BindRecord) {
for _, bindRecord := range h.ch {
bindRecords = append(bindRecords, bindRecord...)
}
return bindRecords
}
// Close closes the session handle.
func (h *SessionHandle) Close() {
for _, bindRecords := range h.ch {
for _, bindRecord := range bindRecords {
updateMetrics(metrics.ScopeSession, bindRecord, nil, false)
}
}
}
// sessionBindInfoKeyType is a dummy type to avoid naming collision in context.
type sessionBindInfoKeyType int
// String defines a Stringer function for debugging and pretty printing.
func (k sessionBindInfoKeyType) String() string {
return "session_bindinfo"
}
// SessionBindInfoKeyType is a variable key for store session bind info.
const SessionBindInfoKeyType sessionBindInfoKeyType = 0