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Discussion items

DM Leadership changes announcement and discussion

    • Jacek will be taking on broader project management responsibilities for entire DM
    • Fritz to back-fill management for qserv team
    • K-T returning from interim Project Engineer to system architect role

Project planning

    • Looking like we will insert a 3-month cycle to break alignment between end-of-cycle and LSST project meetings
    • Review of Jacek's preliminary resource loading matrix for next (3 month) cycle – no objections offhand
    • We should elaborate epics involved in this 3-month cycle (e.g. large-results) with as much detail as is currently known
    • Jacek would like to institute cross-team end-of-sprint demos/reports
    • Jacek concerned about generic, under-specified epic and story definitions – please focus and drive toward more specific definitions

Shared-scan scheduler

    • Design and implementation changes are in progress subsequent to clarification of multiple-DR requirements last week.  John has emailed the group with some design ideas seeking feedback.  Scan balancing and prioritization with multiple DRs requires a somewhat more complicated design.
    • Memory manager "flexi-lock" design needs a revisit to more exactly meet John's needs (design worked and subsequently agreed-upon during meeting, Andy will implement.)
    • Next steps
      • slot in "MemManReal" memory manager implementation which has been provided by Andy
      • update css in qserv_testdata with new shared scan metadata to get integration test coverage
      • spin up the new implementation on in2p3 cluster and begin to test

Secondary Index prototyping

    • Bulk update (sorted interleaved insert/update) experiments running now.  Mike was getting slower results than expected (turned out to be mistaken use of LOAD LOCAL, server-side loading subsequently during meeting looked much better).  Jacek recommends looking into inno-db "reserve" options to pre-flight the load to help performance.

Thread ID

    • LWP-based utility provided by Andy
    • Would be nice to roll into Log package so we don't have to elaborate every log point in qserv code.
    • Ideas developed later in meeting to use TLS ctor, enable via call from C++ code so not enabled all the time for all Log clients.  Andy S will handle.


    • NCSA resources as currently specified will only support non-replicated, single-copy data
    • Should have sufficient resources at IN2P3 to experiment with replicated data


    • Dell willing to provide them with new nvm-express storage for experimentation (like ssd, but directly on pic-express without intervening controller).  Might be interesting to try this out with secondary index.  Fabrice to ask for one machine with 2TB of the new tech to experiment.
    • 25 nodes of cluster have been updated now to Centos 7; we can do the rest after we test them out.
    • Docker updates have been requested, but may take a week or two to get this into puppet scripts and deployed.
    • Fabio inquired about cross-datacenter copying via network.  Right now plans are not to copy data over network.

Multi-node integration tests on single machine (via docker)

    • Vaikunth and Josh have now each run it successfully
    • Need to talk to Josh at JTM about integrating this into CI.  Tricky with current scripts because they use eups build strategy with "qserv-dev" tag explicitly – maybe use lsstw instead for CI to support multiple branches

Vertical Partitioning

    • Test nearly complete.  More or less linear result for 10-20 joins.  Will run tests for order 50 joins, also test on a different storage engine, then write up tech-note with results.


    • Decisions made on which info needed from logs
    • Vaikunth working with Fabrice to run test queries
    • Query-id needed very soon in order to make any use of syslog-gathered info

Sizing model update

    • Probably falls to Fritz' plate from Jacek because Jacek won't have time to drive it
    • Fritz okay to drive issue administratively, but will need technical help because outside areas of expertise
    • Andy H. recommends we include requirement for 40G link per node
    • K-T informs next official refresh is scheduled for Aug., but warns that software and data center designs continue to be made based on current known-obsolete models