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

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Expiry time for memcached cache of interwiki table.

The units are in seconds.