$ ps -elf | grep
...
0 D nobody   27320 27319  2  90  10 - 353471 sleep_ 07:54 ?       00:02:19 /usr/bin/find / -ignore_readdir_race ( -fstype NFS -o -fstype nfs -o -fstype nfs4 -o -fstype afs -o -fstype binfmt_misc -o -fstype proc -o -fstype smbfs -o -fstype autofs -o -fstype iso9660 -o -fstype ncpfs -o -fstype coda -o -fstype devpts -o -fstype ftpfs -o -fstype devfs -o -fstype mfs -o -fstype shfs -o -fstype sysfs -o -fstype cifs -o -fstype lustre_lite -o -fstype tmpfs -o -fstype usbfs -o -fstype udf -o -fstype ocfs2 -o -type d -regex \(^/tmp$\)\|\(^/usr/tmp$\)\|\(^/var/tmp$\)\|\(^/afs$\)\|\(^/amd$\)\|\(^/alex$\)\|\(^/var/spool$\)\|\(^/sfs$\)\|\(^/media$\)\|\(^/var/lib/schroot/mount$\) ) -prune -o -print0                          
...

This job always start automatically and consumes my memory. Even after I kill it, it will starts several hours later.

What's that job?

EDIT

Note: the pid is different from the above because I killed the above one, wait for several hours, then the second one comes.

$ pstree -psl
|-anacron(25920)---sh(25929)---run-parts(25930)---locate(26343)---updatedb.findut(26348)-+-frcode(26358)
|                                                                                        |-sort(26357)
|                                                                                        `-updatedb.findut(26356)---su(26387)---sh(26402)---find(26403)

This is what it look like in a graphical tool: