update_goals is called through the 'Run Goal Challenge Checker'
cron, potentially on a large amount of goals.
With self containing ~400k records a worker has been observed to use
~3.4 GiB. With sensible memory limits this will probably cause the
worker to be killed.
To avoid this turn of prefetching in this initial loop. Performance
shouldn't be affected too much because in the following loop
prefetching for goals will still take place per definition.
opw-1840666
Joren Van Onder
a91512daf6