I have about 580 active products. Even more if you count the non-active.
My /feed/jbtech_products.xml only has 203 products.
max_execution_time 30
memory_limit 90M
max_input_time 60
And when running the update the page doesn't timeout or crash or anything so it does finish.
"Google Base File Complete In 7.416975 Seconds 203 Records"
ZenCart v1.3.7
@version $Id: googlefroogle.php 9 2008-09-20 01:17:30Z numinix $
'GOOGLE_FROOGLE_VERSION', '1.7.0 09.019.2008 17:38:59'
Bookmarks