Hi Haimei, Good work! This doc is comprehensive :)
As for the implementation in IoTDB, here are some points: (1) First, SDT could act as a new Encoding method in IoTDB. It works inside each Page (PageWriter and PageReader). (2) The interface of Encoder could be changed to encode(long time, XX value). The interface of Decoder could be change to getTime(), getXXValue(). Which is, the encoder and decoder is not only responsible for one data column but a series. This involves some reconstruction of the Encoder and Decoder, the data buffers should be stored inside each encoder. (3) For the SDT without timestamps, we need to record the count of each segment. (4) We could offer two encodings, SDT with timestamps and SDT without timestamps. Thanks, -- Jialin Qiao School of Software, Tsinghua University 乔嘉林 清华大学 软件学院 > -----原始邮件----- > 发件人: "runhus...@foxmail.com" <runhus...@foxmail.com> > 发送时间: 2020-09-25 11:56:16 (星期五) > 收件人: dev <dev@iotdb.apache.org> > 抄送: > 主题: Re: Support SDT compression > > Great work！ > > > > Thanks. > > Chao Wang > BONC Ltd > > > From: Eileen Guo > Date: 2020-09-25 11:47 > To: dev > Subject: Support SDT compression > Hi all, > > I've completed a design draft for supporting swinging door compression. > > Jira: jira SDT link > <https://issues.apache.org/jira/browse/IOTDB-890?filter=-4&jql=assignee%20in%20(haimeiguo)%20order%20by%20created%20DESC> > design doc: SDT design doc link > <https://docs.google.com/document/d/1VeTwVsm4CkQSVR65bWw9pKg6gRdiDYUz0lBBhWXHl5A/edit?usp=sharing> > > The doc explains SDT algorithm, compression and decompression process, > performance tests and SDT + IoTDB implementation and usage. > > There is still some question about where to use this algorithm. If you have > any idea, welcome to comment. > > Thank you! > Haimei Guo
