Re: using log4j in user defined system procedure

Tue, 22 Dec 2015 18:00:00 -0800 

Hi Anjana,
I'm not an expert on using log4j but it seems to be loaded with features. I'm confident that you can find a way to force the default Logger to write to a PrintStream which you have created. For instance, I believe that the default logger is an org.apache.logging.log4j.simple.SimpleLogger, and that class has a setStream() method. What you need to do is create a static public method which returns a PrintStream which writes to the file of your choice. Poke that PrintStream into the log4j machinery. You can poke that PrintStream into Derby by pointing derby.stream.error.field at the static public method which you created. 

More inline...

On 12/22/15 9:26 AM, Anjana Prakash wrote:


Hi Rick,


Thanks for follow-up. I looked into the option of 
derby.stream.error.file. However there is issue accessing this value 
of this in system procedure.



My requirement is in system procedure I have implemented log4j. We 
want all the logging from procedure and log level should be using 
derby.log.


Question is


1.Is there any logger API existing in derby that can be used in system 
procedure



2.Is there is way to log to derby.log using log4j from our system 
procedure



What you want to do is force Derby to use the PrintStream being used by 
log4j.



3.We have not set derby.stream.error.file i.e. want the default 
derby.log   Then why is accessing value of derby.stream.error.file 
using system property return null.



I'm afraid I don't understand the question.



4.Also system procedure that refers log4j fail with classnotfound 
exception. Is there is way to log4j in derby.



You want log4j to be visible to the same ClassLoader which contains your 
procedure. If your procedure is in a jar file on the VM classpath, then 
the log4j jar should be on the VM classpath. If  your procedure is in a 
jar file stored in the database, then you want to store the log4j jar in 
the database too and wire it into the database's classpath via the 
derby.database.classpath property.


Hope this helps,
-Rick


Appreciate guidance on same.

Thanks,

Anjana

*From:*Rick Hillegas [mailto:rick.hille...@gmail.com]
*Sent:* Friday, December 18, 2015 8:42 AM
*To:* derby-dev@db.apache.org
*Cc:* Anjana Prakash <anjana.prak...@actian.com>
*Subject:* Re: using log4j in user defined system procedure

On 12/17/15 6:39 AM, Anjana Prakash wrote:

    Hi ,

    Does user defined system procedure enable logging using log4j. or
    using derby.log for logging the output from system procedure.

    Appreciate any reference on same.

    Thanks

    Anjana

Hi Anjana,


Take a look at the derby.stream.error properties documented at 
http://db.apache.org/derby/docs/10.12/ref/crefproper22250.html. Your 
procedure should be able share the diagnostic log with the engine by 
setting derby.stream.error.field or derby.stream.error.file or 
derby.stream.error.method.


Hope this helps,
-Rick

























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