How can I increase the Java max heap size (-Xmx) of a Job calling a child Job with the tRunJob component? Setting -Xmx in JobServer does not seem to have an effect.
Any JVM setting you set in JobServer only applies to the JobServer process. Jobs (parent and child) themselves are run from different JVM processes.
From TAC, select the task of the main Job, then select the JVM parameters tab. Click Add to set the JVM options without rebuilding or redeploying the task:
However, this only applies to the main/parent Job and any child Job where the tRunJob component is not set to run as new/independent process.
If the tRunJob component is set to run as new/independent process, you need to set the JVM at the Job level. Open the child Job in the Run view, click the Advanced settings tab, then select the Use specific JVM arguments checkbox and set the JVM options.
To set this globally, at a Project level, so that it applies to all Jobs: from Studio, navigate to Window > Preferences > Talend > Run/Debug > Job Run VM arguments.