Feedback on Tag Support
dormando at rydia.net
Fri May 9 18:09:25 UTC 2008
Shoot; All of the items that were tagged by that tag. Which could be a
million if you're using tags instead of namespaces.
> On skimming the code it looks like tag invalidating loops over all items
> and removes them from a linked list, then removes the tag from the splay
> Jonathan Ariel wrote:
>> It doesn't seems to be a loop, it says "We use hash and splay tree,
>> make the tag_add and tag_delete commands very quickly, and save memory
>> as much as possible."
>> On Fri, May 9, 2008 at 2:44 PM, Dustin Sallings <dustin at spy.net
>> <mailto:dustin at spy.net>> wrote:
>> On May 9, 2008, at 9:52, John Kramlich wrote:
>>> Is anyone using the variant of memcached v 1.2.4 that supports
>>> tagging found at the following
>>> URLhttp://code.google.com/p/memcached-tag/ ? I am in the planning
>>> stages of major feature additions to my web application and would
>>> really like to use this version. I'm looking for feedback from
>>> others who have used it. Is it stable enough for production use?
>>> Any issues?
>> I think tagging is a generally useful feature, but we honestly
>> haven't put a lot of effort into reviewing the tag code.
>> In particular, we want tagging to be cheap on both setting and
>> invalidating. If either operation has to perform more than a single
>> lookup, then it may not be desirable. In particular, deleting by
>> tag is a loop (within a lock and with another nested loop within
>> it), which may cause the server to hang for long periods of time
>> when invalidating a widely-used tag. It *should* be possible to do
>> this without such a loop.
>> -- Dustin Sallings
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