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Date: Wed, 28 Apr 2004 14:31:45 +0200
To: general@logging.apache.org
From: Ceki =?iso-8859-1?Q?G=FClc=FC?= <ceki@qos.ch>
Subject: Persisting LoggingEvents across languages
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Hi all,

For log4j 1.3, I would like DBAppender, i.e. the successor to JDBCAppender,=
=20
to be able to persist to a database in a format independent of the Java=20
language.

For most fields this is not a problem except for the MDC (a map),=20
properties (a map) and exceptions (an array of type string).

I am thinking of persisting each of these multi-valued fields into their=20
own table. Thus, there will be a table for LoggingEvents containing most=20
fields except for the throwable, MDC and properties.
The MDC field will be stored in its own table, consisting of a foreign key=
=20
to the owning LoggingEvent instance, a column for the key and a column for=
=20
the value. Each row in the MDC table will correspond to one (value,key)=20
pair in an MDC instance. The throwable would also be stored in its own=20
table, with each row corresponding to a line in the stack trace. The=20
properties map will be stored in the same way as the MDC.

The advantage over java object serialization is that none of the fields=20
would be opaque for the database and also programming language independent.=
=20
Thus, one would be able to perform SQL queries on the MDC or the=20
properties. (Give me all the events for userid=3Djohn).

Do log4cxx, log4net, or log4pgp support persistence of logging events into=
=20
a db? Should we work on this in a coordinated fashion?

--=20
Ceki G=FClc=FC

      For log4j documentation consider "The complete log4j manual"
      ISBN: 2970036908 http://www.qos.ch/shop/products/clm_t.jsp =20