So I've been getting warnings from my host lately regarding high CPU and memory use on my VPSs. From what I could tell, the offending process was update-apt-xapi - it would be consuming all the CPU time for hours and use quite a bit of RAM. Some research pointed to the update-apt-xapian-index script in /etc/cron.weekly. It's suppose to be responsible for maintaining an index of packages to speed up search on Synaptic.

Looks something like this:

#!/bin/sh

CMD=/usr/sbin/update-apt-xapian-index
IONICE=/usr/bin/ionice

# Rebuild the index
if [ -x $CMD ]
then
 if [ -x $IONICE ]
 then
  nice $IONICE -c3 $CMD --quiet
 else
  nice $CMD --quiet
 fi
fi

The -n 19 option may already be in place, so in that case simply replace the following:

nice $IONICE -c3 $CMD --quiet

nice $CMD --quiet

with

nice -n 19 $IONICE -c 3 $CMD --update --quiet

nice -n 19 $CMD --update --quiet

First -n 19 flag gives it the least favorable scheduling priority while --update prevents the index from being rebuilt every time. This should reduce CPU use when the script is being run.