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// Copyright 2016 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 executor
import (
"context"
"strings"
"github.com/opentracing/opentracing-go"
"github.com/pingcap/parser/ast"
"github.com/pingcap/parser/charset"
"github.com/pingcap/parser/mysql"
"github.com/pingcap/tidb/expression"
"github.com/pingcap/tidb/meta/autoid"
"github.com/pingcap/tidb/sessionctx"
"github.com/pingcap/tidb/table"
"github.com/pingcap/tidb/table/tables"
"github.com/pingcap/tidb/tablecodec"
"github.com/pingcap/tidb/types"
"github.com/pingcap/tidb/util/logutil"
"github.com/pingcap/tidb/util/memory"
"go.uber.org/zap"
)
var (
_ Executor = &UpdateExec{}
_ Executor = &DeleteExec{}
_ Executor = &InsertExec{}
_ Executor = &ReplaceExec{}
_ Executor = &LoadDataExec{}
)
// updateRecord updates the row specified by the handle `h`, from `oldData` to `newData`.
// `modified` means which columns are really modified. It's used for secondary indices.
// Length of `oldData` and `newData` equals to length of `t.WritableCols()`.
// The return values:
// 1. changed (bool) : does the update really change the row values. e.g. update set i = 1 where i = 1;
// 2. handleChanged (bool) : is the handle changed after the update.
// 3. newHandle (int64) : if handleChanged == true, the newHandle means the new handle after update.
// 4. err (error) : error in the update.
func updateRecord(ctx context.Context, sctx sessionctx.Context, h int64, oldData, newData []types.Datum, modified []bool, t table.Table,
onDup bool, memTracker *memory.Tracker) (bool, bool, int64, error) {
if span := opentracing.SpanFromContext(ctx); span != nil && span.Tracer() != nil {
span1 := span.Tracer().StartSpan("executor.updateRecord", opentracing.ChildOf(span.Context()))
defer span1.Finish()
ctx = opentracing.ContextWithSpan(ctx, span1)
}
txn, err := sctx.Txn(false)
if err != nil {
return false, false, 0, err
}
memUsageOfTxnState := txn.Size()
defer memTracker.Consume(int64(txn.Size() - memUsageOfTxnState))
sc := sctx.GetSessionVars().StmtCtx
changed, handleChanged := false, false
// onUpdateSpecified is for "UPDATE SET ts_field = old_value", the
// timestamp field is explicitly set, but not changed in fact.
onUpdateSpecified := make(map[int]bool)
var newHandle int64
// We can iterate on public columns not writable columns,
// because all of them are sorted by their `Offset`, which
// causes all writable columns are after public columns.
// 1. Cast modified values.
for i, col := range t.Cols() {
if modified[i] {
// Cast changed fields with respective columns.
v, err := table.CastValue(sctx, newData[i], col.ToInfo(), false, false)
if err != nil {
return false, false, 0, err
}
newData[i] = v
}
}
// 2. Handle the bad null error.
for i, col := range t.Cols() {
var err error
if newData[i], err = col.HandleBadNull(newData[i], sc); err != nil {
return false, false, 0, err
}
}
// 3. Compare datum, then handle some flags.
for i, col := range t.Cols() {
collation := newData[i].Collation()
// We should use binary collation to compare datum, otherwise the result will be incorrect.
newData[i].SetCollation(charset.CollationBin)
cmp, err := newData[i].CompareDatum(sc, &oldData[i])
newData[i].SetCollation(collation)
if err != nil {
return false, false, 0, err
}
if cmp != 0 {
changed = true
modified[i] = true
// Rebase auto increment id if the field is changed.
if mysql.HasAutoIncrementFlag(col.Flag) {
recordID, err := getAutoRecordID(newData[i], &col.FieldType, false)
if err != nil {
return false, false, 0, err
}
if err = t.RebaseAutoID(sctx, recordID, true, autoid.RowIDAllocType); err != nil {
return false, false, 0, err
}
}
if col.IsPKHandleColumn(t.Meta()) {
handleChanged = true
newHandle = newData[i].GetInt64()
// Rebase auto random id if the field is changed.
if err := rebaseAutoRandomValue(sctx, t, &newData[i], col); err != nil {
return false, false, 0, err
}
}
} else {
if mysql.HasOnUpdateNowFlag(col.Flag) && modified[i] {
// It's for "UPDATE t SET ts = ts" and ts is a timestamp.
onUpdateSpecified[i] = true
}
modified[i] = false
}
}
sc.AddTouchedRows(1)
// If no changes, nothing to do, return directly.
if !changed {
// See https://dev.mysql.com/doc/refman/5.7/en/mysql-real-connect.html CLIENT_FOUND_ROWS
if sctx.GetSessionVars().ClientCapability&mysql.ClientFoundRows > 0 {
sc.AddAffectedRows(1)
}
physicalID := t.Meta().ID
if pt, ok := t.(table.PartitionedTable); ok {
p, err := pt.GetPartitionByRow(sctx, oldData)
if err != nil {
return false, false, 0, err
}
physicalID = p.GetPhysicalID()
}
unchangedRowKey := tablecodec.EncodeRowKeyWithHandle(physicalID, h)
txnCtx := sctx.GetSessionVars().TxnCtx
if txnCtx.IsPessimistic {
txnCtx.AddUnchangedRowKey(unchangedRowKey)
}
return false, false, 0, nil
}
// 4. Fill values into on-update-now fields, only if they are really changed.
for i, col := range t.Cols() {
if mysql.HasOnUpdateNowFlag(col.Flag) && !modified[i] && !onUpdateSpecified[i] {
if v, err := expression.GetTimeValue(sctx, strings.ToUpper(ast.CurrentTimestamp), col.Tp, int8(col.Decimal)); err == nil {
newData[i] = v
modified[i] = true
} else {
return false, false, 0, err
}
}
}
// 5. If handle changed, remove the old then add the new record, otherwise update the record.
if handleChanged {
if sc.DupKeyAsWarning {
// For `UPDATE IGNORE`/`INSERT IGNORE ON DUPLICATE KEY UPDATE`
// If the new handle exists, this will avoid to remove the record.
err = tables.CheckHandleExists(ctx, sctx, t, newHandle, newData)
if err != nil {
return false, handleChanged, newHandle, err
}
}
if err = t.RemoveRecord(sctx, h, oldData); err != nil {
return false, false, 0, err
}
// the `affectedRows` is increased when adding new record.
if sc.DupKeyAsWarning {
newHandle, err = t.AddRecord(sctx, newData, table.IsUpdate, table.SkipHandleCheck, table.WithCtx(ctx))
} else {
newHandle, err = t.AddRecord(sctx, newData, table.IsUpdate, table.WithCtx(ctx))
}
if err != nil {
return false, false, 0, err
}
if onDup {
sc.AddAffectedRows(1)
}
} else {
// Update record to new value and update index.
if err = t.UpdateRecord(ctx, sctx, h, oldData, newData, modified); err != nil {
return false, false, 0, err
}
if onDup {
sc.AddAffectedRows(2)
} else {
sc.AddAffectedRows(1)
}
}
sc.AddUpdatedRows(1)
sc.AddCopiedRows(1)
return true, handleChanged, newHandle, nil
}
func rebaseAutoRandomValue(sctx sessionctx.Context, t table.Table, newData *types.Datum, col *table.Column) error {
tableInfo := t.Meta()
if !tableInfo.ContainsAutoRandomBits() {
return nil
}
recordID, err := getAutoRecordID(*newData, &col.FieldType, false)
if err != nil {
return err
}
if recordID < 0 {
return nil
}
layout := autoid.NewAutoRandomIDLayout(&col.FieldType, tableInfo.AutoRandomBits)
// Set bits except incremental_bits to zero.
recordID = recordID & (1<<layout.IncrementalBits - 1)
return t.Allocators(sctx).Get(autoid.AutoRandomType).Rebase(tableInfo.ID, recordID, true)
}
// resetErrDataTooLong reset ErrDataTooLong error msg.
// types.ErrDataTooLong is produced in types.ProduceStrWithSpecifiedTp, there is no column info in there,
// so we reset the error msg here, and wrap old err with errors.Wrap.
func resetErrDataTooLong(colName string, rowIdx int, err error) error {
newErr := types.ErrDataTooLong.GenWithStack("Data too long for column '%v' at row %v", colName, rowIdx)
logutil.BgLogger().Error("data too long for column", zap.String("colName", colName), zap.Int("rowIndex", rowIdx))
return newErr
}