STAR C OMPUTING STAR Analysis Operations and Issues Torre Wenaus BNL STAR PWG Videoconference BNL August 13, 1999

STAR C OMPUTING Torre Wenaus, BNL PWG meeting 8/99 Basis of planning CAS processing with DST input based on managed production at the PWG level using the Grand Challenge Architecture Later stage processing on uDSTs (standardized at the PWG level) and ‘nanoDSTs’ (defined by individuals or small groups) occurs under the control of individual physicists and small groups Mix of LSF-based batch, and interactive  and later PROOF-like analysis?  on both Linux and Sun, but with far greater emphasis on Linux For I/O intensive processing, local Linux disks (14GB usable) and Suns available  Usage of local disks and availability of data to be managed through the file catalog

STAR C OMPUTING Torre Wenaus, BNL PWG meeting 8/99 Production Database Components of the (for want of a better term) production database:  File catalogs l Simulation data catalog §populated with all simulation-derived data, from fzd to dst, in HPSS and on disk l Real data catalog §populated with all real raw data in HPSS; dst data and disk resident data not yet in DB (disk raw data shown in web interface)  Run log and online log l fully populated and interfaced to online run log entry  Event tag databases l database of DAQ-level event tags exists. Populated by offline scanner; needs to be interfaced to buffer box  Machine catalog (not yet existing)  Disk volume catalog (not yet existing)

STAR C OMPUTING Torre Wenaus, BNL PWG meeting 8/99 Needed to implement GC in STAR GC client gcaClient interfaced to StIOMaker in root4star  User provides query, or  User provides list of run/events, and components needed  StIOMaker ‘file open’ is submission of query/list to GC  StIOMaker ‘event read’ in event loop is l delivery of ‘this event is ready’ from GC event iterator; files containing needed components are available on disk in locations returned by GC l perform file open/data load for the needed components of the event l proceed to the loop over makers as usual  Will look to user like just another input type handled by StIOMaker GC interface to STAR file catalog  Catalog itself is in place  Currently, event boundaries of files the same for all components l Need to answer ‘what file is each event component in for this event’ in general case l File catalog must include event ranges for files

STAR C OMPUTING Torre Wenaus, BNL PWG meeting 8/99 Grand Challenge queries Queries based on physics tag selections: SELECT (component1, component2, …) FROM dataset_name WHERE (predicate_conditions_on_properties) Example: SELECT dst, hits FROM Run WHERE glb_trk_tot>0 & glb_trk_tot<10 Event components: fzd, raw, dst-xdf, dst-root, hits, StrangeTag, FlowTag, StrangeMuDst, … Mapping from run/event/component to file via the database GC index assembles tags + component file locations for each event Tag based query match yields the files requiring retrieval to serve up that event Event list based queries allow using the GCA for general-purpose coordinated HPSS retrieval Event list based retrieval: SELECT dst, hits Run Event 1 Run Event 24 Run Event 3...

STAR C OMPUTING Torre Wenaus, BNL PWG meeting 8/99 Physics tag generation In doEvents.C based chain (or tacked onto end of bfc)  include StXxxTagMakers in chain  each tag maker provides a tag() method to return tag pointer  gather tags for output in a following maker  Spit them out to a Tag.root or XxxTag.root file(s)  Catalog them along with other event components in DB David Zimmerman is working on writing them out; then  Add them to catalog available to users and use them in GC index building  Add their generation/output to standard production  Multi-file, directory-scanning modes of doEvents.C can be used to process sets of tag files, or they can be catenated StFlowTagMaker* flowMaker = (StFlowTagMaker *) GetMaker("FlowTag"); FlowTag_st* aTag = flowMaker->tag();