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In-file Metadata Considerations . David Malon malon@anl.gov Argonne National Laboratory 22February 2012. In-file metadata. Brief presentation because much/most of what we have considered for in-file metadata has already been discussed on Monday
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In-file Metadata Considerations David Malon malon@anl.gov Argonne National Laboratory 22February 2012
In-file metadata • Brief presentation because much/most of what we have considered for in-file metadata has already been discussed on Monday • Should do a survey of current in-file metadata content • Bookkeeping (complete/incomplete lumiranges, cutflows and counts, …) • Caching of IOV information (from COOL, trigger(?), …) • Summary statistics and information (EventStreamInfo, etc.) • … • Today: further ideas, summary, actions(?) David Malon
Main points thus far • What would we do differently with in-file metadata in mind? • Merging of many kinds of metadata will always take semantic knowledge? • Will always require callout of some kind to user code? • Action: explore new ROOT type-specific merge machinery • Shared event and metadata stream improvements • Multiple itemlists with different write policies, etc. • Some improvements for file merging in general will help metadata • Reference swizzling/remapping • Some metadata are obvious candidates for TKey treatment • Metadata that tend inherently to be one per file • Means to ensure correct output metadata when a stream writes a sequence of files • Design ideas to be summarized • Other actions: means for offline to add metadata to bytestream • What about IOV-style info in bytestream? David Malon