web server - Borland Technical Publications

Defining the Connection Pool Properties for a JDBC Datasource
Table 22.1
maxPreparedStatemen
tCacheSize
Connection Pool Properties for a JDBC Datasource (continued)
Name Allowed Values Description Default Value
Integer
Each connection within a BES
JDBC pool caches
java.sql.PreparedStatement objects
for reuse.
Each PreparedStatement cache is
organized by SQL literal strings
representing unique SQL
statement requests.
This property limits the number of
PreparedStatements cached per
pooled JDBC connection. It
specifies the maximum size of the
cache. If a cache reaches the limit,
any subsequent
javax.sql.Connection.prepareStatem
ent() calls result in non-cached
instances of PreparedStatement
objects being created and
returned to the caller. The lifecycle
of the cache is the same as the
JDBC connection lifecycle. For
example, if an idle connection
times out, both the connection and
its PreparedStatement cache are
discarded. Unresolved
parameterized SQL statements
are cached, for example, the
statement SELECT NAME FROM
CUSTOMER WHERE AGE=20 is cached as
SELECT NAME FROM CUSTOMER WHERE
:age='?'. Note that this property is
only effective when the
reuseStatements property of the
datasource is set to true (default).
The default value is 40, which is
usually sufficient for applications.
40
202 BES Developer’s Guide