// SeekFirst returns an iterator which points to the first entry of the KV index.
func (c *index) SeekFirst(r kv.Retriever) (iter table.IndexIterator, err error) {
it, err := r.Seek(c.prefix)
if err != nil {
return nil, errors.Trace(err)
}
return &indexIter{it: it, idx: c, prefix: c.prefix}, nil
}
// ScanMetaWithPrefix scans metadata with the prefix.
func ScanMetaWithPrefix(retriever kv.Retriever, prefix kv.Key, filter func(kv.Key, []byte) bool) error {
iter, err := retriever.Seek(prefix)
if err != nil {
return errors.Trace(err)
}
defer iter.Close()
for {
if err != nil {
return errors.Trace(err)
}
if iter.Valid() && iter.Key().HasPrefix(prefix) {
if !filter(iter.Key(), iter.Value()) {
break
}
err = iter.Next()
if err != nil {
return errors.Trace(err)
}
} else {
break
}
}
return nil
}
func iterRecords(retriever kv.Retriever, t table.Table, startKey kv.Key, cols []*table.Column,
fn table.RecordIterFunc) error {
it, err := retriever.Seek(startKey)
if err != nil {
return errors.Trace(err)
}
defer it.Close()
if !it.Valid() {
return nil
}
log.Debugf("startKey:%q, key:%q, value:%q", startKey, it.Key(), it.Value())
colMap := make(map[int64]*types.FieldType, len(cols))
for _, col := range cols {
colMap[col.ID] = &col.FieldType
}
prefix := t.RecordPrefix()
for it.Valid() && it.Key().HasPrefix(prefix) {
// first kv pair is row lock information.
// TODO: check valid lock
// get row handle
handle, err := tablecodec.DecodeRowKey(it.Key())
if err != nil {
return errors.Trace(err)
}
rowMap, err := tablecodec.DecodeRow(it.Value(), colMap)
if err != nil {
return errors.Trace(err)
}
data := make([]types.Datum, 0, len(cols))
for _, col := range cols {
if col.IsPKHandleColumn(t.Meta()) {
data = append(data, types.NewIntDatum(handle))
} else {
data = append(data, rowMap[col.ID])
}
}
more, err := fn(handle, data, cols)
if !more || err != nil {
return errors.Trace(err)
}
rk := t.RecordKey(handle)
err = kv.NextUntil(it, util.RowKeyPrefixFilter(rk))
if err != nil {
return errors.Trace(err)
}
}
return nil
}
// Seek searches KV index for the entry with indexedValues.
func (c *index) Seek(r kv.Retriever, indexedValues []types.Datum) (iter table.IndexIterator, hit bool, err error) {
key, _, err := c.GenIndexKey(indexedValues, 0)
if err != nil {
return nil, false, errors.Trace(err)
}
it, err := r.Seek(key)
if err != nil {
return nil, false, errors.Trace(err)
}
// check if hit
hit = false
if it.Valid() && it.Key().Cmp(key) == 0 {
hit = true
}
return &indexIter{it: it, idx: c, prefix: c.prefix}, hit, nil
}
func iterRecords(retriever kv.Retriever, t table.Table, startKey kv.Key, cols []*table.Column,
fn table.RecordIterFunc) error {
it, err := retriever.Seek(startKey)
if err != nil {
return errors.Trace(err)
}
defer it.Close()
if !it.Valid() {
return nil
}
log.Debugf("startKey:%q, key:%q, value:%q", startKey, it.Key(), it.Value())
prefix := t.RecordPrefix()
for it.Valid() && it.Key().HasPrefix(prefix) {
// first kv pair is row lock information.
// TODO: check valid lock
// get row handle
handle, err := tables.DecodeRecordKeyHandle(it.Key())
if err != nil {
return errors.Trace(err)
}
data, err := rowWithCols(retriever, t, handle, cols)
if err != nil {
return errors.Trace(err)
}
more, err := fn(handle, data, cols)
if !more || err != nil {
return errors.Trace(err)
}
rk := t.RecordKey(handle, nil)
err = kv.NextUntil(it, util.RowKeyPrefixFilter(rk))
if err != nil {
return errors.Trace(err)
}
}
return nil
}