web server - Borland Technical Publications

Getting debug output
Table 22.1
maxPreparedStatemen
tsPerQuery
Connection Pool Properties for a JDBC Datasource (continued)
Name Allowed Values Description Default Value
Integer
Under certain conditions such as
high concurrency or when CMP
2.0 entity beans are processed,
more than one PreparedStatement
can be processed concurrently for
the same SQL query on the same
pooled connection. For example, a
SQL query SELECT name FROM table1
WHERE id=? can return distinct result
sets when different values are
used for ?. Although the
PreparedStatement cache has a
single entry for each SQL query,
two or more PreparedStatements can
exist in the cache for the query.
This property specifies the
maximum number of cached
PreparedStatements for a single
query. If the limit is exceeded for a
particular query, subsequent
javax.sql.Connection.prepareStatem
ent() calls result in non-cached
instances of PreparedStatement
objects created and returned to
the caller. Like
maxPreparedStatementCacheSize, this
property is only effective when the
reuseStatements property of the
datasource is set to true (default).
20
Getting debug output
A number of system properties can be set to log activity at datasource, connection
pool, connection and statement levels during application processing. It is not
necessary to configure these properties during normal application runtime execution
but should a situation arise where details of JDBC flow of control is needed these
options are useful. Runtime output generated with these properties set can be provided
to Borland Technical Support to help resolve issues involving JDBC datasource and
connections. Setting these properties for a partition results in log message generation
during JDBC activity. Note that additional log4j configuration is required to ensure that
the messages are actually written to the partition log. Locate the partition's log4j
configuration file, called logConfiguration.xml, and add the following element:
...
...
...
System Property
Name Type Description Default
DataSourceDebug Boolean Reports activity at datasource level for all
datasources
ConnectionPoolDebug Boolean Reports activity at connection pool level for
all datasources
False
False
Chapter 22: Using JDBC 203