func (td *tableDeleter) deleteAllRowsScan(ctx context.Context) error {
tablePrefix := sqlbase.MakeIndexKeyPrefix(
td.rd.helper.tableDesc, td.rd.helper.tableDesc.PrimaryIndex.ID)
span := sqlbase.Span{Start: roachpb.Key(tablePrefix), End: roachpb.Key(tablePrefix).PrefixEnd()}
valNeededForCol := make([]bool, len(td.rd.helper.tableDesc.Columns))
for _, idx := range td.rd.fetchColIDtoRowIndex {
valNeededForCol[idx] = true
}
var rf sqlbase.RowFetcher
err := rf.Init(
td.rd.helper.tableDesc, td.rd.fetchColIDtoRowIndex, &td.rd.helper.tableDesc.PrimaryIndex,
false, false, td.rd.fetchCols, valNeededForCol)
if err != nil {
return err
}
if err := rf.StartScan(td.txn, sqlbase.Spans{span}, 0); err != nil {
return err
}
for {
row, err := rf.NextRow()
if err != nil {
return err
}
if row == nil {
// Done deleting rows.
break
}
_, err = td.row(ctx, row)
if err != nil {
return err
}
}
return td.finalize(ctx)
}
func (sc *SchemaChanger) truncateAndBackfillColumnsChunk(
added []sqlbase.ColumnDescriptor,
dropped []sqlbase.ColumnDescriptor,
defaultExprs []parser.TypedExpr,
evalCtx *parser.EvalContext,
sp sqlbase.Span,
) (roachpb.Key, bool, error) {
var curIndexKey roachpb.Key
done := false
err := sc.db.Txn(func(txn *client.Txn) error {
tableDesc, err := getTableDescFromID(txn, sc.tableID)
if err != nil {
return err
}
// Short circuit the backfill if the table has been deleted.
if tableDesc.Deleted() {
done = true
return nil
}
updateCols := append(added, dropped...)
fkTables := TablesNeededForFKs(*tableDesc, CheckUpdates)
for k := range fkTables {
if fkTables[k], err = getTableDescFromID(txn, k); err != nil {
return err
}
}
// TODO(dan): Tighten up the bound on the requestedCols parameter to
// makeRowUpdater.
requestedCols := make([]sqlbase.ColumnDescriptor, 0, len(tableDesc.Columns)+len(added))
requestedCols = append(requestedCols, tableDesc.Columns...)
requestedCols = append(requestedCols, added...)
ru, err := makeRowUpdater(
txn, tableDesc, fkTables, updateCols, requestedCols, rowUpdaterOnlyColumns,
)
if err != nil {
return err
}
// TODO(dan): This check is an unfortunate bleeding of the internals of
// rowUpdater. Extract the sql row to k/v mapping logic out into something
// usable here.
if !ru.isColumnOnlyUpdate() {
panic("only column data should be modified, but the rowUpdater is configured otherwise")
}
// Run a scan across the table using the primary key. Running
// the scan and applying the changes in many transactions is
// fine because the schema change is in the correct state to
// handle intermediate OLTP commands which delete and add
// values during the scan.
var rf sqlbase.RowFetcher
colIDtoRowIndex := colIDtoRowIndexFromCols(tableDesc.Columns)
valNeededForCol := make([]bool, len(tableDesc.Columns))
for i := range valNeededForCol {
_, valNeededForCol[i] = ru.fetchColIDtoRowIndex[tableDesc.Columns[i].ID]
}
err = rf.Init(tableDesc, colIDtoRowIndex, &tableDesc.PrimaryIndex, false, false,
tableDesc.Columns, valNeededForCol)
if err != nil {
return err
}
// StartScan uses 0 as a sentinal for the default limit of entries scanned.
if err := rf.StartScan(txn, sqlbase.Spans{sp}, 0); err != nil {
return err
}
indexKeyPrefix := sqlbase.MakeIndexKeyPrefix(tableDesc, tableDesc.PrimaryIndex.ID)
oldValues := make(parser.DTuple, len(ru.fetchCols))
updateValues := make(parser.DTuple, len(updateCols))
writeBatch := &client.Batch{}
var i int
for ; i < ColumnTruncateAndBackfillChunkSize; i++ {
row, err := rf.NextRow()
if err != nil {
return err
}
if row == nil {
break // Done
}
curIndexKey, _, err = sqlbase.EncodeIndexKey(
tableDesc, &tableDesc.PrimaryIndex, colIDtoRowIndex, row, indexKeyPrefix)
for j, col := range added {
if defaultExprs == nil || defaultExprs[j] == nil {
updateValues[j] = parser.DNull
} else {
updateValues[j], err = defaultExprs[j].Eval(evalCtx)
if err != nil {
return err
}
}
if !col.Nullable && updateValues[j].Compare(parser.DNull) == 0 {
return sqlbase.NewNonNullViolationError(col.Name)
}
}
for j := range dropped {
updateValues[j+len(added)] = parser.DNull
}
copy(oldValues, row)
for j := len(row); j < len(oldValues); j++ {
oldValues[j] = parser.DNull
}
if _, err := ru.updateRow(writeBatch, oldValues, updateValues); err != nil {
return err
}
}
if i < ColumnTruncateAndBackfillChunkSize {
done = true
}
if err := txn.Run(writeBatch); err != nil {
return convertBackfillError(tableDesc, writeBatch)
}
return nil
})
return curIndexKey.PrefixEnd(), done, err
}