Files
tidb/br/pkg/kv/session.go

254 lines
6.7 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,
// 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 kv
import (
"context"
"fmt"
"strconv"
"github.com/pingcap/parser/model"
"github.com/pingcap/parser/mysql"
"github.com/pingcap/tidb/kv"
"github.com/pingcap/tidb/sessionctx"
"github.com/pingcap/tidb/sessionctx/variable"
)
// Pair is a pair of key and value.
type Pair struct {
// Key is the key of the KV pair
Key []byte
// Val is the value of the KV pair
Val []byte
// IsDelete represents whether we should remove this KV pair.
IsDelete bool
}
// invalidIterator is a trimmed down Iterator type which is invalid.
type invalidIterator struct {
kv.Iterator
}
// TableHasAutoRowID return whether table has auto generated row id.
func TableHasAutoRowID(info *model.TableInfo) bool {
return !info.PKIsHandle && !info.IsCommonHandle
}
// Valid implements the kv.Iterator interface.
func (*invalidIterator) Valid() bool {
return false
}
// Close implements the kv.Iterator interface.
func (*invalidIterator) Close() {
}
type kvMemBuf struct {
kv.MemBuffer
kvPairs []Pair
size int
}
func (mb *kvMemBuf) Set(k kv.Key, v []byte) error {
mb.kvPairs = append(mb.kvPairs, Pair{
Key: k.Clone(),
Val: append([]byte{}, v...),
})
mb.size += len(k) + len(v)
return nil
}
func (mb *kvMemBuf) SetWithFlags(k kv.Key, v []byte, ops ...kv.FlagsOp) error {
return mb.Set(k, v)
}
func (mb *kvMemBuf) Delete(k kv.Key) error {
mb.kvPairs = append(mb.kvPairs, Pair{
Key: k.Clone(),
Val: []byte{},
IsDelete: true,
})
mb.size += len(k)
return nil
}
func (mb *kvMemBuf) DeleteWithFlags(k kv.Key, ops ...kv.FlagsOp) error {
return mb.Delete(k)
}
// Release publish all modifications in the latest staging buffer to upper level.
func (mb *kvMemBuf) Release(h kv.StagingHandle) {
}
func (mb *kvMemBuf) Staging() kv.StagingHandle {
return 0
}
// Cleanup cleanup the resources referenced by the StagingHandle.
// If the changes are not published by `Release`, they will be discarded.
func (mb *kvMemBuf) Cleanup(h kv.StagingHandle) {}
// Size returns sum of keys and values length.
func (mb *kvMemBuf) Size() int {
return mb.size
}
// Len returns the number of entries in the DB.
func (t *transaction) Len() int {
return t.GetMemBuffer().Len()
}
type kvUnionStore struct {
kvMemBuf
}
func (s *kvUnionStore) GetMemBuffer() kv.MemBuffer {
return &s.kvMemBuf
}
func (s *kvUnionStore) GetIndexName(tableID, indexID int64) string {
panic("Unsupported Operation")
}
func (s *kvUnionStore) CacheIndexName(tableID, indexID int64, name string) {
}
func (s *kvUnionStore) CacheTableInfo(id int64, info *model.TableInfo) {
}
// transaction is a trimmed down Transaction type which only supports adding a
// new KV pair.
type transaction struct {
kv.Transaction
kvUnionStore
}
func (t *transaction) GetMemBuffer() kv.MemBuffer {
return &t.kvUnionStore.kvMemBuf
}
func (t *transaction) Discard() {
// do nothing
}
func (t *transaction) Flush() (int, error) {
// do nothing
return 0, nil
}
// Reset implements the kv.MemBuffer interface.
func (t *transaction) Reset() {}
// Get implements the kv.Retriever interface.
func (t *transaction) Get(ctx context.Context, key kv.Key) ([]byte, error) {
return nil, kv.ErrNotExist
}
// Iter implements the kv.Retriever interface.
func (t *transaction) Iter(k kv.Key, upperBound kv.Key) (kv.Iterator, error) {
return &invalidIterator{}, nil
}
// Set implements the kv.Mutator interface.
func (t *transaction) Set(k kv.Key, v []byte) error {
return t.kvMemBuf.Set(k, v)
}
// Delete implements the kv.Mutator interface.
func (t *transaction) Delete(k kv.Key) error {
return t.kvMemBuf.Delete(k)
}
// GetTableInfo implements the kv.Transaction interface.
func (t *transaction) GetTableInfo(id int64) *model.TableInfo {
return nil
}
// CacheTableInfo implements the kv.Transaction interface.
func (t *transaction) CacheTableInfo(id int64, info *model.TableInfo) {
}
// session is a trimmed down Session type which only wraps our own trimmed-down
// transaction type and provides the session variables to the TiDB library
// optimized for Lightning.
type session struct {
sessionctx.Context
txn transaction
vars *variable.SessionVars
// currently, we only set `CommonAddRecordCtx`
values map[fmt.Stringer]interface{}
}
// SessionOptions is the initial configuration of the session.
type SessionOptions struct {
SQLMode mysql.SQLMode
Timestamp int64
RowFormatVersion string
}
func newSession(options *SessionOptions) *session {
sqlMode := options.SQLMode
vars := variable.NewSessionVars()
vars.SkipUTF8Check = true
vars.StmtCtx.InInsertStmt = true
vars.StmtCtx.BatchCheck = true
vars.StmtCtx.BadNullAsWarning = !sqlMode.HasStrictMode()
vars.StmtCtx.TruncateAsWarning = !sqlMode.HasStrictMode()
vars.StmtCtx.OverflowAsWarning = !sqlMode.HasStrictMode()
vars.StmtCtx.AllowInvalidDate = sqlMode.HasAllowInvalidDatesMode()
vars.StmtCtx.IgnoreZeroInDate = !sqlMode.HasStrictMode() || sqlMode.HasAllowInvalidDatesMode()
vars.StmtCtx.TimeZone = vars.Location()
_ = vars.SetSystemVar("timestamp", strconv.FormatInt(options.Timestamp, 10))
_ = vars.SetSystemVar(variable.TiDBRowFormatVersion, options.RowFormatVersion)
vars.TxnCtx = nil
s := &session{
vars: vars,
values: make(map[fmt.Stringer]interface{}, 1),
}
return s
}
func (se *session) takeKvPairs() ([]Pair, int) {
pairs := se.txn.kvMemBuf.kvPairs
size := se.txn.kvMemBuf.Size()
se.txn.kvMemBuf.kvPairs = make([]Pair, 0, len(pairs))
se.txn.kvMemBuf.size = 0
return pairs, size
}
// Txn implements the sessionctx.Context interface.
func (se *session) Txn(active bool) (kv.Transaction, error) {
return &se.txn, nil
}
// GetSessionVars implements the sessionctx.Context interface.
func (se *session) GetSessionVars() *variable.SessionVars {
return se.vars
}
// SetValue saves a value associated with this context for key.
func (se *session) SetValue(key fmt.Stringer, value interface{}) {
se.values[key] = value
}
// Value returns the value associated with this context for key.
func (se *session) Value(key fmt.Stringer) interface{} {
return se.values[key]
}
// StmtAddDirtyTableOP implements the sessionctx.Context interface.
func (se *session) StmtAddDirtyTableOP(op int, physicalID int64, handle kv.Handle) {}