Frequently Asked Questions

1. General questions
   1. What is SDSS Log Viewer? What can I do with it?
   2. What background knowledge is expected?
   3. How should I learn the tool
2. Technical questions
   1. Why I cannot run the tool?
   2. Why do I see nothing other than the timeline?
   3. Why do the tool stop at "Rendering visualization"?
   4. Why do a Java "Bad Version Exception" occur?
   5. Why do the tool run very slow or even stop?
3. Support and Collaboration
   1. Who designed the tool?
   2. Are the source codes available?

Answers

1. General Questions
   1. What is SDSS Log Viewer? What can I do with it?

      SDSS Log Viewer is an information visualization tool that can process, visualize, and analyze the SDSS' SQL query log data with interactive features, e.g. zoom in and out, details on demand, tool tips, dynamic query and etc.. The tool is designed with Java SD language and the Prefuse visualization toolkit. It has the following functions:

      • View and interact the SDSS SQL traffic on the time unit of a day, a month, and a year.
      • View and interact contents of SDSS SQL query logs.
      • View and interact sky areas specified by SDSS SQL queries.
   2. What background knowledge is expected?

      Knowledge of Sloan Digital Sky Survey is necessary. Knowledge of SQL query for retrieving data from SDSS data archive is a plus. Knowledge with basic Java running environment would help a lot.

      Ideally, knowing the SDSS SQL query log could fully take advantage of the tool.

   3. How should I learn the tool

      Read through the Manual page will be a good practice to learn the tool.

      Check the Interesting Cases page. You might find useful insights of the SDSS SQL log data, and know capabilities of the tool.

2. Technical questions
   1. Why I cannot run the tool?

      This problem is mainly due to two issues:

      • Your Java JRE (Java Running Environment) is an older version. To run this tool, you need a JRE version 6 or latest. This problem is severe in Mac machines, which do not automatically update their JRE. A possible solution can be found on "Java in Mac OS" in the download page. In Windows machines, auto-update is not a problem.
      • The log CSV data you used might have some fields compromised. If this occurred, the tool may stop running. Download your data again, and try not to edit the CSV data.
   2. Why do I see nothing other than the timeline?

      The initial GUI of SDSS Log Viewer ONLY shows the timeline view. You need to use the "Open Data File" function, either from the "File" menu, or from the icon at the toolbar, to open a SDSS SQL log CSV file.

   3. Why do the tool stop at "Rendering visualization"?

      This is mainly due to bad log data, which are seen frequently in data at early 2003. So avoid using data from this period.

   4. Why do a Java "Bad Version Exception" occur?

      Please update your Java JRE to version 6.0 or latest. This problem is seen in many Mac computers, purchased a few years ago. A possible solution can be found on "Java in Mac OS" in the download page.

   5. Why do the tool run very slow or even stop?

      Close the tool, and run it again. The tool needs a large amount of memory. When visualize too many rounds, e.g. rendering ~50 times, it will use the maximum reserved memory and become very slow and even stop working.

Support and Collaboration

1. Who designed the tool?

   The tool is designed by Jian Zhang during his Ph.D study at Drexel University, You can find me at about me. Any questions regarding using this tool and results I present in the cases and demos should go to me.

   Want to collaborate on similar log data? Ask me. I am interested in any kinds of collaborations.

2. Are the source codes available?

   Please email me about the source codes. You can find my email from my home page