Hi, In the current TsFile structure, PageHeader and PageData are compactly put together in a Chunk, like a chain structure [1].
The basic unit that is read from the hard disk each time is the Chunk. For the query scenario of device * sensor, it would appear that we read too much data, so we considered a new optimization direction: use PageHeaders to filter the data first, then we can be more precise about which Pages need to be read.. But we still have a debate about where to put the PageHeaders: 1.put the PageHeader into the ChunkMetaData. The nice thing about this is that we can start filtering the data once the IO is done. 2.put the PageHeader in the ChunkHeader. so we need to read the PageHeader one more time, but the advantage is that we save more memory when we read the List of the device. For details, please see [2] What do you think? Regards, --- Dawei Liu [1] https://user-images.githubusercontent.com/33376433/69341240-26012300-0ca4-11ea-91a1-d516810cad44.png <https://user-images.githubusercontent.com/33376433/69341240-26012300-0ca4-11ea-91a1-d516810cad44.png> [2] https://issues.apache.org/jira/secure/attachment/12994279/131582515824_.pic_hd.jpg <https://issues.apache.org/jira/secure/attachment/12994279/131582515824_.pic_hd.jpg>
