[Mondrian] RE: MDX Logger

Julian Hyde jhyde at pentaho.org
Wed Jan 30 19:50:36 EST 2008

RE: bug 1863097, "Log For Mdx"


> Will Gorman wrote:
> I added a new log4j Logger ("mondrian.mdx") to
> RolapConnection.execute(query) for logging the MDX statements.  I also
> configured the log4j.xml file to dump those statements out to 
> an mdx.log
> file.  Do we want to log any additional information about the MDX
> statement?  

I'd like to see the elapsed time to execute the statement. Unlike the SQL
tracing, you can't print this information on the same line, because it might
take a long time to execute an MDX statement. You should print the statement
id and the MDX when the statement starts, and print the elapsed time when it
finishes execution.

You may need to invent a statement id. Statement id will help people using
the olap4j driver, because olap4j/JDBC have a better defined concept of
'statement' than mondrian does currently. I guess use an ascending integer
counter inside RolapResult for now. Some time in the future we will create a
statement & session tables inside MondrianServer, but not now.

> Should I update Mondrian's approach for logging the SQL 
> statements in a
> similar manner?  Right now the SQL log includes execution 
> time, is that
> something we want to log with this new approach, or should that be
> logged separately?

Right now SQL tracing is controlled by the property mondrian.trace.level. I
would like to obsolete that before we release 3.0, and have everything
controlled by log4j properties.

> Also, in which html doc should I add this information to?  
> Right now the
> configuration.html doc does not include a log4j configuration 
> / logging
> section, but that might be a natural place for this to live.

Configuration.html is the right place for this. Yes, there should be a log4j
config section. I found it difficult to set up without.

Also, as part of this change, please obliterate all references
mondrian.trace.level in the code and the doc.


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