1. An Interactive Browser For BaBar Databases
Adeyemi Adesanya
Stanford Linear Accelerator Center
11/5/2019

2. *
07/16/96
Why?
We need an interactive Objectivity/DB utilities, for physicists and administrators
Program supplied by vendor offers limited functionality and does not scale
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3. BaBar’s Functional Demands
Scalability! 64k database files
Presenting the right abstraction
No general external product is BaBar-aware
A logical, BaBar database hierarchy needs to be incorporated
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4. Java
Suitability:
Comprehensive set of GUI components
Platform independent for wide deployment
Objectivity/Java binding has limitations related to language interoperability (today).
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5. CORBA
A STANDARD for distributed inter-object communication (
ORB’s form the middleware layer along with the IIOP
Java/C++ ORB bindings readily available
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6. The framework 100% Java provides the client GUI
C++ servers handle Objectivity access
1 server process per Objectivity federation
NamingService stores server addresses
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8. Key features View the Database & Event collection hierarchy
Iterate through collections using simple selection (tags)
Access individual events and browse their headers
Identify “cloned” components
Scan a collection for databases
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12. CORBA performance A high-level protocol, not an alternative to TCP-IP!
Data marshalling is a major factor
Consider size/complexity of data types
Database IO overshadows CORBA latency
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13. Minimizing the overhead
Server: Models the GUI components
No persistent objects are converted to CORBA
Transactions are kept as short as possible
Warn user of locking issues if necessary
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14. The TAO ORB Designed for real-time environments
Aim is reliable, predictable CORBA service
Optimized client & server stubs
Fine grained thread control
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15. Multithreading Reduce idle CPU time during IO tasks
Exploit multiprocessor hardware
Priority control
two models currently in use:
thread-per-connection
thread pool
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16. Future: admin. tools Browser database tasks strictly read-only
Develop separate GUI for administrators
Aid import/export of files between sites
Search engine
Drag and drop files and event collections
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17. Summary CORBA offers: 100% Java for platform independent GUIs
distributed object communication
platform interoperability
more than just a transport protocol
100% Java for platform independent GUIs
Not all ORBs are created equally
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