Files
tidb/bindinfo/session_handle.go
2019-08-26 10:30:40 +08:00

124 lines
3.8 KiB
Go

// 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/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
}
// appendBindMeta addes the BindMeta to the cache, all the stale bindMetas are
// removed from the cache after this operation.
func (h *SessionHandle) appendBindMeta(hash string, meta *BindMeta) {
// Make sure there is only one goroutine writes the cache.
h.ch.removeStaleBindMetas(hash, meta, metrics.ScopeSession)
h.ch[hash] = append(h.ch[hash], meta)
meta.updateMetrics(metrics.ScopeSession, true)
}
func (h *SessionHandle) newBindMeta(record *BindRecord) (hash string, meta *BindMeta, err error) {
hash = parser.DigestHash(record.OriginalSQL)
stmtNodes, _, err := h.parser.Parse(record.BindSQL, record.Charset, record.Collation)
if err != nil {
return "", nil, err
}
meta = &BindMeta{BindRecord: record, HintsSet: CollectHint(stmtNodes[0])}
return hash, meta, nil
}
// AddBindRecord new a BindRecord with BindMeta, add it to the cache.
func (h *SessionHandle) AddBindRecord(record *BindRecord) error {
record.CreateTime = types.Time{
Time: types.FromGoTime(time.Now()),
Type: mysql.TypeDatetime,
Fsp: 3,
}
record.UpdateTime = record.CreateTime
// update the BindMeta to the cache.
hash, meta, err := h.newBindMeta(record)
if err == nil {
h.appendBindMeta(hash, meta)
}
return err
}
// DropBindRecord drops a BindRecord in the cache.
func (h *SessionHandle) DropBindRecord(record *BindRecord) {
meta := &BindMeta{BindRecord: record}
meta.Status = deleted
hash := parser.DigestHash(record.OriginalSQL)
h.ch.removeDeletedBindMeta(hash, meta, metrics.ScopeSession)
h.appendBindMeta(hash, meta)
}
// GetBindRecord return the BindMeta of the (normdOrigSQL,db) if BindMeta exist.
func (h *SessionHandle) GetBindRecord(normdOrigSQL, db string) *BindMeta {
hash := parser.DigestHash(normdOrigSQL)
bindRecords := h.ch[hash]
if bindRecords != nil {
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 []*BindMeta) {
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 {
bindRecord.updateMetrics(metrics.ScopeSession, 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