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Data Management. Machine / Application State Data. Outline. EPICS Archiver Gathering related datasets File vs. database storage. EPICS Archiver. EPICS toolkit does provide an archiver > 100,000 different signals are archived at SNS (various rates)
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J-PARC Data Management Machine / Application State Data
Outline EPICS Archiver Gathering related datasets File vs. database storage
EPICS Archiver EPICS toolkit does provide an archiver > 100,000 different signals are archived at SNS (various rates) Great for looking for unanticipated correlations between different effects Is beam loss related to cooling temperature? Great for seeing what failed first Uses the time of arrival to the archiver as the time-stamp Not good for fine-scale time resolution (< 1 sec) Cumbersome to gather collected sets of large amounts of data What were all the magnets in a beamline set to at 11:23:01 AM on 05/11/2008 ?
EPICS Archive Viewer CSS – Powerful archive -viewer
Collected Data Set Storage Why Bother ? Often applications do not work in the control room when connected to live data for the first time. It is useful to have a “beam replay” mode for diagnosing application problems after a beam shift (i.e. the next day after you’ve slept some). When analyzing beam behavior at some moment, it is useful to know the value of all the magnets / BPM readings at that time – difficult to do with the Archiver
XAL Services – A Digression Services are headless executables (no GUI) Run continuously in the background Typically on one instance runs Sometimes more than one instance can run across servers Provides remote communication with user interfaces XAL defines an API for communication between client and service Uses open standards XML-RPC for communication mDNS for dynamic service discovery
PV-Logger Service It will grab a prescribed set of PVs as a collection Can prescribe a collection rate Can trigger on demand a set e.g. when a beam measurement is done Can define many independent sets of data to log These definition sets are defined in a database Data sets are stored in a database Allows easy browsing Other tools can access these sets (e.g. Online Model)
Machine Save – Compare-Restore (SCORE) In order to restore the state of a machine, need to capture all settable values in the beamline Magnet fields, RF amplitude/phases, foil poisition, timing setup, … Need to monitor readback values for these devices A power supply could be tripped Need convenient restore mechanism Need convenient browsing of save-sets Viewable comments helpful
USPAS Data Storage: File vs. Database • File Storage • Pros • Easy to implement • Can readily get you hands on the information (editor) • Cons • Problem archiving • Not easy to browse contents of many files • Database • Pros • Easy management of old data • Wealth of query tools available • Cons • More trouble for the initial deployment
File Data Storage Useful for Physics Application Setup Information What sequence is used, what range is being scanned, plot configurations, etc. Can be used for data storage as well XML data format is used in XAL See gov.sns.tools.xml.samples Easy to create hierarchal storage Typically this type configuration is managed in the “document” part of the application (document – view – control architecture model)