func (rs *localRegion) getRowsFromSelectReq(ctx *selectContext) error {
// Init ctx.colTps and use it to decode all the rows.
columns := ctx.sel.TableInfo.Columns
ctx.colTps = make(map[int64]*types.FieldType, len(columns))
for _, col := range columns {
if col.GetPkHandle() {
continue
}
ctx.colTps[col.GetColumnId()] = distsql.FieldTypeFromPBColumn(col)
}
kvRanges := rs.extractKVRanges(ctx)
limit := int64(-1)
if ctx.sel.Limit != nil {
limit = ctx.sel.GetLimit()
}
for _, ran := range kvRanges {
if limit == 0 {
break
}
count, err := rs.getRowsFromRange(ctx, ran, limit, ctx.descScan)
if err != nil {
return errors.Trace(err)
}
limit -= count
}
if ctx.aggregate {
return rs.getRowsFromAgg(ctx)
}
return nil
}
func (h *rpcHandler) getChunksFromSelectReq(ctx *selectContext) ([]tipb.Chunk, error) {
// Init ctx.colTps and use it to decode all the rows.
columns := ctx.sel.TableInfo.Columns
ctx.colTps = make(map[int64]*types.FieldType, len(columns))
for _, col := range columns {
if col.GetPkHandle() {
continue
}
ctx.colTps[col.GetColumnId()] = distsql.FieldTypeFromPBColumn(col)
}
kvRanges, desc := h.extractKVRanges(ctx)
limit := int64(-1)
if ctx.sel.Limit != nil {
limit = ctx.sel.GetLimit()
}
var chunks []tipb.Chunk
var err error
for _, ran := range kvRanges {
if limit == 0 {
break
}
chunks, err = h.getRowsFromRange(ctx, ran, &limit, desc, chunks)
if err != nil {
return nil, errors.Trace(err)
}
}
if ctx.aggregate {
return h.getRowsFromAgg(ctx)
}
return chunks, nil
}
// Put column values into ctx, the values will be used for expr evaluation.
func (rs *localRegion) setColumnValueToCtx(ctx *selectContext, h int64, row map[int64][]byte, cols map[int64]*tipb.ColumnInfo) error {
for colID, col := range cols {
if col.GetPkHandle() {
if mysql.HasUnsignedFlag(uint(col.GetFlag())) {
ctx.eval.Row[colID] = types.NewUintDatum(uint64(h))
} else {
ctx.eval.Row[colID] = types.NewIntDatum(h)
}
} else {
data := row[colID]
ft := distsql.FieldTypeFromPBColumn(col)
datum, err := tablecodec.DecodeColumnValue(data, ft)
if err != nil {
return errors.Trace(err)
}
ctx.eval.Row[colID] = datum
}
}
return nil
}