I suspect asking this means my usage is wrong, but here goes.
There's no way to "touch" a cached entry to update the expires time,
correct?
So, I have a pretty large item cached. It's mostly read only. It has an
expires time, but every time it's read (or written) I want to extend the
expires time. Basically I want an inactivity time out on the cached item --
keep it in the cache as long as it's being used within a time period.
I can write the item back to memcached each time, but that seems a bit of a
waste if the item does not change (and it's large).
Or I can avoid setting an expires on the item itself and have a separate
second item that is just used to expire the item. Trade off here is I'm
doing an extra memcached access
each time.
if ( get( expires_key ) ) {
item = get( key );
set( expires_key, 1, expires_seconds );
}
else {
item = fetch_item();
set( key, item );
set( expires_key, 1, expires_seconds );
}
That's not exactly correct. In this specific case that fetch_item()
requires re-authorization for the item, but that's not really pertinent.
Does it matter that the item doesn't have an expires time in this case? Or
is there any reason to set a very long expires on the item and a short
expires on the cache item that tracks the real expires time?
IIRC, memcached will toss out "expired" items first, then items w/o an
expires time when memory is needed. Are there stats that will show the
difference?
Thanks,
--
Bill Moseley
[email protected]
