Logging is an important means of gaining insight into your application's runtime behavior. Kodo provides a flexible logging system that integrates with many existing runtime systems, such as application servers and servlet runners.
There are four built-in logging plugins: a default logging framework that covers most needs, a Log4J delegate, an Apache Commons Logging delegate, and a no-op implementation for disabling logging.
Warning | |
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Logging can have a negative impact on performance. Disable
verbose logging (such as logging of SQL statements) before
running any performance tests. It is advisable to limit or
disable logging for a production system. You can
disable logging altogether by setting
the |
Logging is done over a number of logging channels, each of which has a logging level which controls the verbosity of log messages recorded for the channel. Kodo uses the following logging channels:
kodo.Tool
: Messages issued by the Kodo
command line and Ant tools. Most messages
are basic statements detailing which classes or files the
tools are running on. Detailed output is only available via
the logging category the tool belongs to, such as
kodo.Enhance
for the enhancer
(see Section 5.2, “Enhancement”) or
kodo.MetaData
for the mapping tool
(see Section 7.1, “Forward Mapping”).
This logging category is provided so that you can
get a general idea of what a tool is doing without having to
manipulate logging settings that might also affect runtime
behavior.
kodo.Configuration
: Messages issued
by the configuration framework.
kodo.Enhance
: Messages pertaining to
enhancement and runtime class generation.
kodo.MetaData
: Details about the generation
of metadata and object-relational mappings.
kodo.Runtime
: General Kodo runtime messages.
kodo.Query
: Messages about queries.
Query strings and any parameter values, if applicable, will be
logged to the TRACE
level at execution
time. Information about possible performance concerns
will be logged to the INFO
level.
kodo.jdbc.JDBC
: JDBC connection information.
General JDBC information will be logged to the TRACE
level. Information about possible performance
concerns will be logged to the INFO
level.
kodo.jdbc.SQL
: This is the most common
logging channel to use. Detailed information about the
execution of SQL statements will be sent to the
TRACE
level. It is useful to enable this
channel if you are curious about the exact SQL that Kodo
issues to the datastore.
When using the built-in Kodo logging facilities, you can
enable SQL logging by adding SQL=TRACE
to
your kodo.Log
property.
Kodo can optionally reformat the logged SQL to
make it easier to read. To enable pretty-printing,
add PrettyPrint=true
to the
kodo.ConnectionFactoryProperties
property. You can control how many columns wide the
pretty-printed SQL will be with the
PrettyPrintLineLength
property. The default
line length is 60 columns.
While pretty printing makes things easier to read, it can make output harder to process with tools like grep.
Pretty-printing properties configuration might look like so:
JPA XML format:
<property name="kodo.Log" value="SQL=TRACE"/> <property name="kodo.ConnectionFactoryProperties" value="MaxActive=100, PrettyPrint=true, PrettyPrintLineLength=72"/>
JDO properties format:
kodo.Log: SQL=TRACE kodo.ConnectionFactoryProperties: MaxActive=100, PrettyPrint=true, PrettyPrintLineLength=72
kodo.jdbc.Schema
: Details about operations
on the database schema.
kodo.Profile
: Information related to Kodo's
profiling framework.