Notes from the fourth memcached hackathon of undetermined frequency

Trond Norbye Trond.Norbye at Sun.COM
Wed Apr 16 18:14:10 UTC 2008

On Apr 16, 2008, at 9:52 AM, Dustin Sallings wrote:
> 	Stats are ugly and required a lot of thought.  We tried to hold of  
> on designing a mechanism as long as we could (Trond suggested we  
> wait for, you know, someone to care), but in the end, we decided to  
> do something like an implied multi-get since Dormando claims to care  
> a lot.  Enough to implement it anyway.  :)
> 	A stats command is issued with a single string parameter, and the  
> server returns multiple responses, each containing a key, and a  
> string value.  A terminating packet indicates the server has nothing  
> more to say.  [We didn't really talk about the details of this, but  
> I'd recommend terminating with a stat with a 0 length key and 0  
> length value.]

I was thinking of this on my drive home trying to figure out a  
solution, and I was thinking that a better solution might be to return  
an "xml" document (yes, I know you all are screaming now).. But.. who  
is the main consumer for the stats command? well it is some sort of a  
management agent. Most languages contains libraries to parse xml- 
documents, so it should be easy for them to "suck out" the data they  
need (and it's not that much overhead to create it)..

XML is a verbose format, but if we return a single "packet" pr stat- 
item we add a 24 byte header for each item so I don't know if we  
actually save anything by using single packets over the tag-overhead  
in xml...

Well, that's just an idea. (I think it will be easier to create a  
management agent to use the data if it is encoded in XML with all the  
XML libraries out there).. but then again, I didn't see the point of  
creating the stats command before we had an actual use-case for the  
command ;-)

The other thing I remembered in the car was that the version-command  
is not specified in the protocol. I sent a suggestion for it a time  
ago to the mailing list.. any comments on that format, or should we go  
ahead and use it?

Too bad I didn't see Toru's suggestion, but I was so tired that I had  
to drive home :( Anyway I had a great time last night, and it was nice  
to meet all of you.


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