An Interactive Browser For BaBar Databases Adeyemi Adesanya Stanford Linear Accelerator Center 11/5/2019 yemi@slac.stanford.edu

* 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 11/5/2019 yemi@slac.stanford.edu *

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 11/5/2019 yemi@slac.stanford.edu

Java Suitability: Comprehensive set of GUI components Platform independent for wide deployment Objectivity/Java binding has limitations related to language interoperability (today). 11/5/2019 yemi@slac.stanford.edu

CORBA A STANDARD for distributed inter-object communication (http://www.omg.org) ORB’s form the middleware layer along with the IIOP Java/C++ ORB bindings readily available 11/5/2019 yemi@slac.stanford.edu

The framework 100% Java provides the client GUI C++ servers handle Objectivity access 1 server process per Objectivity federation NamingService stores server addresses 11/5/2019 yemi@slac.stanford.edu

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 11/5/2019 yemi@slac.stanford.edu

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 11/5/2019 yemi@slac.stanford.edu

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 11/5/2019 yemi@slac.stanford.edu

The TAO ORB Designed for real-time environments Aim is reliable, predictable CORBA service Optimized client & server stubs Fine grained thread control 11/5/2019 yemi@slac.stanford.edu

Multithreading Reduce idle CPU time during IO tasks Exploit multiprocessor hardware Priority control two models currently in use: thread-per-connection thread pool 11/5/2019 yemi@slac.stanford.edu

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 11/5/2019 yemi@slac.stanford.edu

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 11/5/2019 yemi@slac.stanford.edu