Manual:$wgInterwikiExpiry

Interwiki cache: $wgInterwikiExpiry
Expiry time for memcached cache of interwiki table.
Introduced in version:1.2.6
Removed in version:Still in use
Allowed values:Unspecified
Default value:10800 (3 hours)

Details

Expiry time for memcached cache of interwiki table.

The units are in seconds.