func (rs *localRegion) getIndexRowFromRange(ctx *selectContext, ran kv.KeyRange, desc bool, limit int64) (count int64, err error) {
idxInfo := ctx.sel.IndexInfo
txn := ctx.txn
var seekKey kv.Key
if desc {
seekKey = ran.EndKey
} else {
seekKey = ran.StartKey
}
ids := make([]int64, len(idxInfo.Columns))
for i, col := range idxInfo.Columns {
ids[i] = col.GetColumnId()
}
for {
if limit == 0 {
break
}
var it kv.Iterator
if desc {
it, err = txn.SeekReverse(seekKey)
if err != nil {
return 0, errors.Trace(err)
}
seekKey = it.Key()
} else {
it, err = txn.Seek(seekKey)
if err != nil {
return 0, errors.Trace(err)
}
seekKey = it.Key().PrefixNext()
}
if !it.Valid() {
break
}
if desc {
if it.Key().Cmp(ran.StartKey) < 0 {
break
}
} else {
if it.Key().Cmp(ran.EndKey) >= 0 {
break
}
}
values, b, err1 := tablecodec.CutIndexKey(it.Key(), ids)
if err1 != nil {
return 0, errors.Trace(err1)
}
var handle int64
if len(b) > 0 {
var handleDatum types.Datum
_, handleDatum, err = codec.DecodeOne(b)
if err != nil {
return 0, errors.Trace(err)
}
handle = handleDatum.GetInt64()
} else {
handle, err = decodeHandle(it.Value())
if err != nil {
return 0, errors.Trace(err)
}
}
gotRow, err := rs.valuesToRow(ctx, handle, values)
if err != nil {
return 0, errors.Trace(err)
}
if gotRow {
limit--
count++
}
}
return count, nil
}
func (h *rpcHandler) getIndexRowFromRange(ctx *selectContext, ran kv.KeyRange, desc bool, limit int64) ([]*tipb.Row, error) {
idxInfo := ctx.sel.IndexInfo
startKey := maxStartKey(ran.StartKey, h.startKey)
endKey := minEndKey(ran.EndKey, h.endKey)
if limit == 0 || bytes.Compare(startKey, endKey) >= 0 {
return nil, nil
}
var rows []*tipb.Row
var seekKey kv.Key
if desc {
seekKey = endKey
} else {
seekKey = startKey
}
ids := make([]int64, len(idxInfo.Columns))
for i, col := range idxInfo.Columns {
ids[i] = col.GetColumnId()
}
for {
if limit == 0 {
break
}
var (
pairs []Pair
pair Pair
err error
)
if desc {
pairs = h.mvccStore.ReverseScan(startKey, seekKey, 1, ctx.sel.GetStartTs())
} else {
pairs = h.mvccStore.Scan(seekKey, endKey, 1, ctx.sel.GetStartTs())
}
if len(pairs) > 0 {
pair = pairs[0]
}
if pair.Err != nil {
// TODO: handle lock error.
return nil, errors.Trace(pair.Err)
}
if pair.Key == nil {
break
}
if desc {
if bytes.Compare(pair.Key, startKey) < 0 {
break
}
seekKey = pair.Key
} else {
if bytes.Compare(pair.Key, endKey) >= 0 {
break
}
seekKey = []byte(kv.Key(pair.Key).PrefixNext())
}
values, b, err := tablecodec.CutIndexKey(pair.Key, ids)
var handle int64
if len(b) > 0 {
var handleDatum types.Datum
_, handleDatum, err = codec.DecodeOne(b)
if err != nil {
return nil, errors.Trace(err)
}
handle = handleDatum.GetInt64()
} else {
handle, err = decodeHandle(pair.Value)
if err != nil {
return nil, errors.Trace(err)
}
}
row, err := h.valuesToRow(ctx, handle, values)
if err != nil {
return nil, errors.Trace(err)
}
if row != nil {
rows = append(rows, row)
limit--
}
}
return rows, nil
}