SQL/MX 3.2.1 Guide to Stored Procedures in Java (H06.26+, J06.15+)

Scope of JVM Startup Options in an MXCI Session

During an MXCI session, you can issue a CONTROL QUERY DEFAULT statement that sets the

UDR_JAVA_OPTIONS default attribute. This setting applies only to CALL statements that you issue

in MXCI after you issue the CONTROL QUERY DEFAULT statement.

For example, the first CONTROL QUERY DEFAULT statement sets the class path for the SPJ

environment of subsequent CALL statements that you issue in MXCI. When you call the LOWERPRICE

procedure after issuing the CONTROL QUERY DEFAULT statement, the JVM uses the

/usr/otherclasses class path to search for and load classes that are not in the external path

of that SPJ. The second CONTROL QUERY DEFAULT statement resets the UDR_JAVA_OPTIONS

setting to the class path in effect, if any, at the start of the current MXCI session:

>>CALL samdbcat.sales.monthlyorders(1,?);

NUMBER

-----------

--- SQL operation complete.

>>CONTROL QUERY DEFAULT UDR_JAVA_OPTIONS

'-Djava.class.path=/usr/myclasses';

--- SQL operation complete.

>>CALL samdbcat.sales.lowerprice();

--- SQL operation complete.

>>CONTROL QUERY DEFAULT UDR_JAVA_OPTIONS RESET;

--- SQL operation complete.

For more information about MXCI, see the SQL/MX Reference Manual.

Displaying the UDR_JAVA_OPTIONS in Effect for an MXCI Session

To show the UDR_JAVA_OPTIONS setting in effect for a CONTROL QUERY DEFAULT statement

issued in MXCI, enter the SHOWCONTROL command in the current MXCI session. For more

information about SHOWCONTROL, see the SQL/MX Reference Manual.

Using Multiple UDR_JAVA_OPTIONS Settings in One Application

In the same application, you can set multiple UDR_JAVA_OPTIONS, each of which controls the

JVM startup options in an SPJ environment. Two or more UDR_JAVA_OPTIONS settings are

considered different or identical, depending on how you specify them in CONTROL QUERY

DEFAULT statements. See Determining the Uniqueness of UDR_JAVA_OPTIONS Settings (page 39).

If you specify different UDR_JAVA_OPTIONS settings in the same application, be aware of the

Performance Considerations of Using Multiple UDR_JAVA_OPTIONS Settings (page 40).

Determining the Uniqueness of UDR_JAVA_OPTIONS Settings

Two or more UDR_JAVA_OPTIONS settings are considered to be different when their character

string literals do not match during a case-sensitive string comparison. The case, white space, and

order in which the options appear within each character string literal must be the same for

UDR_JAVA_OPTIONS settings to be considered identical.

For example, these UDR_JAVA_OPTIONS settings in separate CONTROL QUERY DEFAULT

statements are considered to be the same:

CONTROL QUERY DEFAULT UDR_JAVA_OPTIONS

'-Xmx32M -Djava.class.path=/usr/otherclasses';

Controlling JVM Startup Options 39