[wp-trac] [WordPress Trac] #23059: if object cache entry for last_changed in term and comments groups is purged, it invalidase too many cached items

[WordPress Trac]

#23059: if object cache entry for last_changed in term and comments groups is
purged, it invalidase too many cached items
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 Reporter:  mark-k        |       Owner:
     Type:  defect (bug)  |      Status:  new
 Priority:  normal        |   Milestone:  Awaiting Review
Component:  Cache         |     Version:  3.5
 Severity:  normal        |  Resolution:
 Keywords:                |
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Comment (by ryan):

 > This might be an edge case, but IMO it means that whenever
 'last_changed' is purged/garbage collected all the terms related cached
 values are practically invalidated as well.
 > I really don't understand why the value is part of the cache key at all,
 but if it has to be shouldn't it be stored in a less volatile storage?

 Invalidating the caches is the entire purpose of last_changed. When
 anything term related is changed, last_updated is bumped and all term
 related query caches are passively invalidated as a result. Caches with
 old last_updated values will eventually be pushed out of the cache and
 garbage collected.

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Ticket URL: <http://core.trac.wordpress.org/ticket/23059#comment:2>
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