func (rs *localRegion) getRowsFromRange(ctx *selectContext, ran kv.KeyRange, limit int64, desc bool) ([]*tipb.Row, error) {
if limit == 0 {
return nil, nil
}
var rows []*tipb.Row
if ran.IsPoint() {
_, err := ctx.txn.Get(ran.StartKey)
if terror.ErrorEqual(err, kv.ErrNotExist) {
return nil, nil
} else if err != nil {
return nil, errors.Trace(err)
}
h, err := tablecodec.DecodeRowKey(ran.StartKey)
if err != nil {
return nil, errors.Trace(err)
}
match, err := rs.evalWhereForRow(ctx, h)
if err != nil {
return nil, errors.Trace(err)
}
if !match {
return nil, nil
}
row, err := rs.getRowByHandle(ctx, h)
if err != nil {
return nil, errors.Trace(err)
}
if row != nil {
rows = append(rows, row)
}
return rows, nil
}
var seekKey kv.Key
if desc {
seekKey = ran.EndKey
} else {
seekKey = ran.StartKey
}
for {
if limit == 0 {
break
}
var (
it kv.Iterator
err error
)
if desc {
it, err = ctx.txn.SeekReverse(seekKey)
} else {
it, err = ctx.txn.Seek(seekKey)
}
if err != nil {
return nil, errors.Trace(err)
}
if !it.Valid() {
break
}
if desc {
if it.Key().Cmp(ran.StartKey) < 0 {
break
}
seekKey = tablecodec.TruncateToRowKeyLen(it.Key())
} else {
if it.Key().Cmp(ran.EndKey) >= 0 {
break
}
seekKey = it.Key().PrefixNext()
}
h, err := tablecodec.DecodeRowKey(it.Key())
if err != nil {
return nil, errors.Trace(err)
}
match, err := rs.evalWhereForRow(ctx, h)
if err != nil {
return nil, errors.Trace(err)
}
if !match {
continue
}
row, err := rs.getRowByHandle(ctx, h)
if err != nil {
return nil, errors.Trace(err)
}
if row != nil {
rows = append(rows, row)
limit--
}
}
return rows, nil
}
func (h *rpcHandler) getRowsFromRange(ctx *selectContext, ran kv.KeyRange, limit int64, desc bool) ([]*tipb.Row, error) {
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
if ran.IsPoint() {
val, err := h.mvccStore.Get(startKey, ctx.sel.GetStartTs())
if len(val) == 0 {
return nil, nil
} else if err != nil {
return nil, errors.Trace(err)
}
handle, err := tablecodec.DecodeRowKey(kv.Key(startKey))
if err != nil {
return nil, errors.Trace(err)
}
match, err := h.evalWhereForRow(ctx, handle)
if err != nil {
return nil, errors.Trace(err)
}
if !match {
return nil, nil
}
row, err := h.getRowByHandle(ctx, handle)
if err != nil {
return nil, errors.Trace(err)
}
if row != nil {
rows = append(rows, row)
}
return rows, nil
}
var seekKey []byte
if desc {
seekKey = endKey
} else {
seekKey = startKey
}
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 = []byte(tablecodec.TruncateToRowKeyLen(kv.Key(pair.Key)))
} else {
if bytes.Compare(pair.Key, endKey) >= 0 {
break
}
seekKey = []byte(kv.Key(pair.Key).PrefixNext())
}
handle, err := tablecodec.DecodeRowKey(pair.Key)
if err != nil {
return nil, errors.Trace(err)
}
match, err := h.evalWhereForRow(ctx, handle)
if err != nil {
return nil, errors.Trace(err)
}
if !match {
continue
}
row, err := h.getRowByHandle(ctx, handle)
if err != nil {
return nil, errors.Trace(err)
}
if row != nil {
rows = append(rows, row)
limit--
}
}
return rows, nil
}