man page index isn't rebuilt after yum update

Issue

• After yum updates, running a man -k $PHRASE results in 'nothing appropriate':

[root@localhost ~]# man -k vg
vg: nothing appropriate

• However, after waiting overnight, the -k option works:

[root@localhost ~]# man -k vg
setfont              (8)  - load EGA/VGA console screen font
showconsolefont      (8)  - Show the current EGA/VGA console screen font
vgcfgbackup          (8)  - backup volume group descriptor area
vgcfgrestore         (8)  - restore volume group descriptor area
vgchange             (8)  - change attributes of a volume group
vgck                 (8)  - check volume group metadata
vgconvert            (8)  - convert volume group metadata format
vgcreate             (8)  - create a volume group
vgdisplay            (8)  - display attributes of volume groups
vgexport             (8)  - make volume groups unknown to the system
vgextend             (8)  - add physical volumes to a volume group
vgimport             (8)  - make exported volume groups known to the system
vgimportclone        (8)  - import and rename duplicated volume group (e.g. a hardware snapshot)
vgmerge              (8)  - merge two volume groups
vgmknodes            (8)  - recreate volume group directory and logical volume special files
vgreduce             (8)  - reduce a volume group
vgremove             (8)  - remove a volume group
vgrename             (8)  - rename a volume group
vgs                  (8)  - report information about volume groups
vgscan               (8)  - scan all disks for volume groups and rebuild caches
vgsplit              (8)  - split a volume group into two