mirror of
https://github.com/go-gitea/gitea.git
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431 lines
12 KiB
Go
431 lines
12 KiB
Go
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// Copyright 2015 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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// See the License for the specific language governing permissions and
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// limitations under the License.
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package ddl
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import (
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"github.com/juju/errors"
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"github.com/ngaut/log"
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"github.com/pingcap/tidb/ast"
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"github.com/pingcap/tidb/column"
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"github.com/pingcap/tidb/kv"
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"github.com/pingcap/tidb/meta"
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"github.com/pingcap/tidb/model"
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"github.com/pingcap/tidb/table"
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"github.com/pingcap/tidb/table/tables"
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"github.com/pingcap/tidb/terror"
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)
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func (d *ddl) adjustColumnOffset(columns []*model.ColumnInfo, indices []*model.IndexInfo, offset int, added bool) {
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offsetChanged := make(map[int]int)
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if added {
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for i := offset + 1; i < len(columns); i++ {
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offsetChanged[columns[i].Offset] = i
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columns[i].Offset = i
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}
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columns[offset].Offset = offset
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} else {
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for i := offset + 1; i < len(columns); i++ {
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offsetChanged[columns[i].Offset] = i - 1
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columns[i].Offset = i - 1
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}
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columns[offset].Offset = len(columns) - 1
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}
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// TODO: index can't cover the add/remove column with offset now, we may check this later.
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// Update index column offset info.
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for _, idx := range indices {
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for _, col := range idx.Columns {
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newOffset, ok := offsetChanged[col.Offset]
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if ok {
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col.Offset = newOffset
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}
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}
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}
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}
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func (d *ddl) addColumn(tblInfo *model.TableInfo, colInfo *model.ColumnInfo, pos *ast.ColumnPosition) (*model.ColumnInfo, int, error) {
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// Check column name duplicate.
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cols := tblInfo.Columns
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position := len(cols)
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// Get column position.
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if pos.Tp == ast.ColumnPositionFirst {
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position = 0
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} else if pos.Tp == ast.ColumnPositionAfter {
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c := findCol(cols, pos.RelativeColumn.Name.L)
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if c == nil {
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return nil, 0, errors.Errorf("No such column: %v", pos.RelativeColumn)
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}
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// Insert position is after the mentioned column.
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position = c.Offset + 1
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}
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colInfo.State = model.StateNone
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// To support add column asynchronous, we should mark its offset as the last column.
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// So that we can use origin column offset to get value from row.
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colInfo.Offset = len(cols)
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// Insert col into the right place of the column list.
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newCols := make([]*model.ColumnInfo, 0, len(cols)+1)
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newCols = append(newCols, cols[:position]...)
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newCols = append(newCols, colInfo)
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newCols = append(newCols, cols[position:]...)
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tblInfo.Columns = newCols
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return colInfo, position, nil
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}
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func (d *ddl) onAddColumn(t *meta.Meta, job *model.Job) error {
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schemaID := job.SchemaID
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tblInfo, err := d.getTableInfo(t, job)
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if err != nil {
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return errors.Trace(err)
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}
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col := &model.ColumnInfo{}
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pos := &ast.ColumnPosition{}
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offset := 0
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err = job.DecodeArgs(col, pos, &offset)
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if err != nil {
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job.State = model.JobCancelled
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return errors.Trace(err)
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}
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columnInfo := findCol(tblInfo.Columns, col.Name.L)
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if columnInfo != nil {
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if columnInfo.State == model.StatePublic {
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// we already have a column with same column name
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job.State = model.JobCancelled
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return errors.Errorf("ADD COLUMN: column already exist %s", col.Name.L)
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}
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} else {
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columnInfo, offset, err = d.addColumn(tblInfo, col, pos)
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if err != nil {
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job.State = model.JobCancelled
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return errors.Trace(err)
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}
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// Set offset arg to job.
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if offset != 0 {
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job.Args = []interface{}{columnInfo, pos, offset}
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}
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}
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_, err = t.GenSchemaVersion()
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if err != nil {
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return errors.Trace(err)
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}
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switch columnInfo.State {
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case model.StateNone:
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// none -> delete only
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job.SchemaState = model.StateDeleteOnly
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columnInfo.State = model.StateDeleteOnly
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err = t.UpdateTable(schemaID, tblInfo)
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return errors.Trace(err)
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case model.StateDeleteOnly:
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// delete only -> write only
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job.SchemaState = model.StateWriteOnly
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columnInfo.State = model.StateWriteOnly
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err = t.UpdateTable(schemaID, tblInfo)
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return errors.Trace(err)
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case model.StateWriteOnly:
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// write only -> reorganization
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job.SchemaState = model.StateWriteReorganization
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columnInfo.State = model.StateWriteReorganization
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// initialize SnapshotVer to 0 for later reorganization check.
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job.SnapshotVer = 0
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err = t.UpdateTable(schemaID, tblInfo)
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return errors.Trace(err)
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case model.StateWriteReorganization:
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// reorganization -> public
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// get the current version for reorganization if we don't have
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reorgInfo, err := d.getReorgInfo(t, job)
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if err != nil || reorgInfo.first {
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// if we run reorg firstly, we should update the job snapshot version
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// and then run the reorg next time.
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return errors.Trace(err)
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}
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tbl, err := d.getTable(schemaID, tblInfo)
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if err != nil {
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return errors.Trace(err)
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}
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err = d.runReorgJob(func() error {
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return d.backfillColumn(tbl, columnInfo, reorgInfo)
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})
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if terror.ErrorEqual(err, errWaitReorgTimeout) {
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// if timeout, we should return, check for the owner and re-wait job done.
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return nil
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}
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if err != nil {
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return errors.Trace(err)
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}
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// Adjust column offset.
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d.adjustColumnOffset(tblInfo.Columns, tblInfo.Indices, offset, true)
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columnInfo.State = model.StatePublic
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if err = t.UpdateTable(schemaID, tblInfo); err != nil {
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return errors.Trace(err)
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}
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// finish this job
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job.SchemaState = model.StatePublic
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job.State = model.JobDone
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return nil
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default:
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return errors.Errorf("invalid column state %v", columnInfo.State)
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}
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}
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func (d *ddl) onDropColumn(t *meta.Meta, job *model.Job) error {
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schemaID := job.SchemaID
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tblInfo, err := d.getTableInfo(t, job)
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if err != nil {
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return errors.Trace(err)
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}
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var colName model.CIStr
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err = job.DecodeArgs(&colName)
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if err != nil {
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job.State = model.JobCancelled
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return errors.Trace(err)
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}
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colInfo := findCol(tblInfo.Columns, colName.L)
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if colInfo == nil {
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job.State = model.JobCancelled
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return errors.Errorf("column %s doesn't exist", colName)
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}
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if len(tblInfo.Columns) == 1 {
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job.State = model.JobCancelled
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return errors.Errorf("can't drop only column %s in table %s", colName, tblInfo.Name)
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}
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// we don't support drop column with index covered now.
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// we must drop the index first, then drop the column.
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for _, indexInfo := range tblInfo.Indices {
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for _, col := range indexInfo.Columns {
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if col.Name.L == colName.L {
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job.State = model.JobCancelled
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return errors.Errorf("can't drop column %s with index %s covered now", colName, indexInfo.Name)
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}
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}
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}
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_, err = t.GenSchemaVersion()
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if err != nil {
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return errors.Trace(err)
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}
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switch colInfo.State {
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case model.StatePublic:
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// public -> write only
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job.SchemaState = model.StateWriteOnly
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colInfo.State = model.StateWriteOnly
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// set this column's offset to the last and reset all following columns' offset
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d.adjustColumnOffset(tblInfo.Columns, tblInfo.Indices, colInfo.Offset, false)
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err = t.UpdateTable(schemaID, tblInfo)
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return errors.Trace(err)
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case model.StateWriteOnly:
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// write only -> delete only
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job.SchemaState = model.StateDeleteOnly
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colInfo.State = model.StateDeleteOnly
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err = t.UpdateTable(schemaID, tblInfo)
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return errors.Trace(err)
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case model.StateDeleteOnly:
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// delete only -> reorganization
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job.SchemaState = model.StateDeleteReorganization
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colInfo.State = model.StateDeleteReorganization
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// initialize SnapshotVer to 0 for later reorganization check.
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job.SnapshotVer = 0
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err = t.UpdateTable(schemaID, tblInfo)
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return errors.Trace(err)
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case model.StateDeleteReorganization:
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// reorganization -> absent
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reorgInfo, err := d.getReorgInfo(t, job)
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if err != nil || reorgInfo.first {
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// if we run reorg firstly, we should update the job snapshot version
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// and then run the reorg next time.
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return errors.Trace(err)
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}
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tbl, err := d.getTable(schemaID, tblInfo)
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if err != nil {
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return errors.Trace(err)
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}
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err = d.runReorgJob(func() error {
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return d.dropTableColumn(tbl, colInfo, reorgInfo)
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})
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if terror.ErrorEqual(err, errWaitReorgTimeout) {
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// if timeout, we should return, check for the owner and re-wait job done.
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return nil
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}
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if err != nil {
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return errors.Trace(err)
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}
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// all reorganization jobs done, drop this column
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newColumns := make([]*model.ColumnInfo, 0, len(tblInfo.Columns))
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for _, col := range tblInfo.Columns {
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if col.Name.L != colName.L {
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newColumns = append(newColumns, col)
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}
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}
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tblInfo.Columns = newColumns
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if err = t.UpdateTable(schemaID, tblInfo); err != nil {
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return errors.Trace(err)
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}
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// finish this job
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job.SchemaState = model.StateNone
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job.State = model.JobDone
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return nil
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default:
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return errors.Errorf("invalid table state %v", tblInfo.State)
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}
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}
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// How to backfill column data in reorganization state?
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// 1. Generate a snapshot with special version.
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// 2. Traverse the snapshot, get every row in the table.
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// 3. For one row, if the row has been already deleted, skip to next row.
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// 4. If not deleted, check whether column data has existed, if existed, skip to next row.
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// 5. If column data doesn't exist, backfill the column with default value and then continue to handle next row.
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func (d *ddl) backfillColumn(t table.Table, columnInfo *model.ColumnInfo, reorgInfo *reorgInfo) error {
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seekHandle := reorgInfo.Handle
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version := reorgInfo.SnapshotVer
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for {
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handles, err := d.getSnapshotRows(t, version, seekHandle)
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if err != nil {
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return errors.Trace(err)
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} else if len(handles) == 0 {
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return nil
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}
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seekHandle = handles[len(handles)-1] + 1
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err = d.backfillColumnData(t, columnInfo, handles, reorgInfo)
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if err != nil {
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return errors.Trace(err)
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}
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}
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}
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func (d *ddl) backfillColumnData(t table.Table, columnInfo *model.ColumnInfo, handles []int64, reorgInfo *reorgInfo) error {
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for _, handle := range handles {
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log.Info("[ddl] backfill column...", handle)
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err := kv.RunInNewTxn(d.store, true, func(txn kv.Transaction) error {
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if err := d.isReorgRunnable(txn); err != nil {
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return errors.Trace(err)
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}
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// First check if row exists.
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exist, err := checkRowExist(txn, t, handle)
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if err != nil {
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return errors.Trace(err)
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} else if !exist {
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// If row doesn't exist, skip it.
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return nil
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}
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backfillKey := t.RecordKey(handle, &column.Col{ColumnInfo: *columnInfo})
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backfillValue, err := txn.Get(backfillKey)
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if err != nil && !kv.IsErrNotFound(err) {
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return errors.Trace(err)
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}
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if backfillValue != nil {
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return nil
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}
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value, _, err := table.GetColDefaultValue(nil, columnInfo)
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if err != nil {
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return errors.Trace(err)
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}
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// must convert to the column field type.
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v, err := value.ConvertTo(&columnInfo.FieldType)
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if err != nil {
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return errors.Trace(err)
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}
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err = lockRow(txn, t, handle)
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if err != nil {
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return errors.Trace(err)
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}
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err = tables.SetColValue(txn, backfillKey, v)
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if err != nil {
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return errors.Trace(err)
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}
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return errors.Trace(reorgInfo.UpdateHandle(txn, handle))
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})
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if err != nil {
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return errors.Trace(err)
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}
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}
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return nil
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}
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func (d *ddl) dropTableColumn(t table.Table, colInfo *model.ColumnInfo, reorgInfo *reorgInfo) error {
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version := reorgInfo.SnapshotVer
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seekHandle := reorgInfo.Handle
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col := &column.Col{ColumnInfo: *colInfo}
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for {
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handles, err := d.getSnapshotRows(t, version, seekHandle)
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if err != nil {
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return errors.Trace(err)
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} else if len(handles) == 0 {
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return nil
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}
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seekHandle = handles[len(handles)-1] + 1
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err = kv.RunInNewTxn(d.store, true, func(txn kv.Transaction) error {
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if err1 := d.isReorgRunnable(txn); err1 != nil {
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return errors.Trace(err1)
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}
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var h int64
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for _, h = range handles {
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key := t.RecordKey(h, col)
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err1 := txn.Delete(key)
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if err1 != nil && !terror.ErrorEqual(err1, kv.ErrNotExist) {
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return errors.Trace(err1)
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}
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}
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return errors.Trace(reorgInfo.UpdateHandle(txn, h))
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})
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if err != nil {
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return errors.Trace(err)
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}
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}
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}
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