[Boston.pm] pre-extending strings for apache/mod-perl application

I have an apache/mod-perl application that can results in large xml 
strings which are then transformed by xslt into html. A database query 
can result in an xml string with a length greater than 300,000 . In a 
normal perl allocation you can pre-extend the string to prevent repeated 
new allocations and copies. Does anyone know what happens in a mod-perl 
application? Does pre-extending have any benefit?

Don Leslie