ROOT I/O Meeting

Friday 21 Jun 2019, 16:00 → 17:40 Europe/Zurich

32/1-A24 (CERN)

Brian Paul Bockelman (University of Nebraska-Lincoln (US)), Philippe Canal (Fermi National Accelerator Lab. (US))

Attendees: Philippe, Jakob, Axel, Guilherme, Oksana.

Jakob: Spend time in Mainz.  Talked about PhD student dram disk.  Agreed in principle, need to write 2 pages project description.  He has 2 candidates in mind.  Dateline for submission is in October.  Nice chat with Stefan, RooFit may be a customer for RTuple since it has a concept of interchangeable backend and also has some vector operations.

Jakob: Plan for summer: improvements for RTuple, focused on the storage side, memory management, storage access routines/interface.  (one goal is to have asynchronous interface) … and benchmarks.

Chep2019:  Jakob’s talk is accepted as oral.  Oksana’s talk as poster.

Oksana: Introducing Alfonso the GSOC student working on compression.

Alfonso: Working on incorporating Zstd, cleaning up the existing PR.   To take advantage of Zstd, we will need to update TBasket and the like.

Oksana: lz4 can use compression dictionary but it can not generate them … we need Zstd for that.

Axel: humm but lz4 in normal operation is creating a compression dictionary.  Could we update the code so that we can capture it?

Axel: One thing we could do is to ‘capture’ the compression dictionary after the first basket and re-use for the the other basket.  This might be a generic solution without needing Zstd.

Alfonso: We also need to understand the cases where the compression is not very successfull.

Oksana: In Kiev dealing with PhD bureaucracy.  

Guilherme: RAS.

Philippe: TClonesArray streaming: add support for v5 TF1 and TFormula.   Add support for changing the data type (user driven.

Axel:  Trying to get the release done …. (And talked to Jakob about the RTuple code) … Will be working on asynchronous part of RTuple (still using TFile for now).

 

Meetings:  Oksana will chair the I/O meeting for the next 6 weeks.

 

16:00 → 16:20 Round Table