本文整理匯總了Golang中github.com/pingcap/tidb/kv.Iterator類的典型用法代碼示例。如果您正苦於以下問題：Golang Iterator類的具體用法？Golang Iterator怎麽用？Golang Iterator使用的例子？那麽, 這裏精選的類代碼示例或許可以為您提供幫助。
在下文中一共展示了Iterator類的5個代碼示例，這些例子默認根據受歡迎程度排序。您可以為喜歡或者感覺有用的代碼點讚，您的評價將有助於係統推薦出更棒的Golang代碼示例。
示例1: getIndexRowFromRange
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
}示例2: getRowsFromRange
func (rs *localRegion) getRowsFromRange(ctx *selectContext, ran kv.KeyRange, limit int64, desc bool) (count int64, err error) {
if limit == 0 {
return 0, nil
}
if ran.IsPoint() {
var value []byte
value, err = ctx.txn.Get(ran.StartKey)
if terror.ErrorEqual(err, kv.ErrNotExist) {
return 0, nil
} else if err != nil {
return 0, errors.Trace(err)
}
var h int64
h, err = tablecodec.DecodeRowKey(ran.StartKey)
if err != nil {
return 0, errors.Trace(err)
}
gotRow, err1 := rs.handleRowData(ctx, h, value)
if err1 != nil {
return 0, errors.Trace(err1)
}
if gotRow {
count++
}
return
}
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 0, 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 0, errors.Trace(err)
}
gotRow, err := rs.handleRowData(ctx, h, it.Value())
if err != nil {
return 0, errors.Trace(err)
}
if gotRow {
limit--
count++
}
}
return count, nil
}示例3: getRowsFromRange
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
}示例4: getIndexRowFromRange
func getIndexRowFromRange(idxInfo *tipb.IndexInfo, txn kv.Transaction, ran kv.KeyRange, desc bool, limit int64) ([]*tipb.Row, error) {
var rows []*tipb.Row
var seekKey kv.Key
if desc {
seekKey = ran.EndKey
} else {
seekKey = ran.StartKey
}
for {
if limit == 0 {
break
}
var it kv.Iterator
var err error
if desc {
it, err = txn.SeekReverse(seekKey)
if err != nil {
return nil, errors.Trace(err)
}
seekKey = it.Key()
} else {
it, err = txn.Seek(seekKey)
if err != nil {
return nil, 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
}
}
datums, err := tablecodec.DecodeIndexKey(it.Key())
if err != nil {
return nil, errors.Trace(err)
}
var handle types.Datum
if len(datums) > len(idxInfo.Columns) {
handle = datums[len(idxInfo.Columns)]
datums = datums[:len(idxInfo.Columns)]
} else {
var intHandle int64
intHandle, err = decodeHandle(it.Value())
if err != nil {
return nil, errors.Trace(err)
}
handle.SetInt64(intHandle)
}
data, err := codec.EncodeValue(nil, datums...)
if err != nil {
return nil, errors.Trace(err)
}
handleData, err := codec.EncodeValue(nil, handle)
if err != nil {
return nil, errors.Trace(err)
}
row := &tipb.Row{Handle: handleData, Data: data}
rows = append(rows, row)
limit--
}
return rows, nil
}示例5: valToStr
func valToStr(c *C, iter kv.Iterator) string {
val := iter.Value()
return string(val)
}