Hi Lars
My question is not about loading the delta loading mechanism which is at the application level ,I am more concern about the database layer , once the data is loaded how the existing records will be modified if the same record was already there and some changes happened to the existing data, how it differentiates which one to consider
Also whether it overwrites the existing data or it keeps both records with time factors to differntiate past and current information.
Thanks
Hello Santosh,
HANA employs multi-version concurrency to manage data changes and to evaluate which records are valid to which transaction at any given time.
Once there are entries in the delta log, it will always be considered during command execution.
A more detailled explanation of the technical solution is not (yet) documented in a public way.
regards,
Lars
Thanks Lars I came across merginig process while looking at the architecture ,do merging and multi-version concurrency have any relation ?
Yes Manoj in BW we have adding mechanism incase of infocubes and overwrite & add incase of DSO, several other mechanisms which help us to handle delta changes.How Hana handles all the changes in data , Thanks for your inputs.
Edited by: varada santosh on Mar 4, 2012 5:36 AM
edited by me
Hi Manoj
Thanks for your quick response ,but what I am looking at it is at the core of HANA , how the changes are handled, like in BW the before ,after ,reverse image ,0recordmode etc forms the base for delta process.what is the technique in HANA to handle changes in data whether it overwrites ,add it and how it manages time dependency.
Add comment