

 Membase: A distributed key-value database for modern web applications - tzury
http://www.membase.org/

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chewbranca
I'm curious to read more about Membase, their current homepage is rather
sparse and lacking in content, but one of the things that really intrigues me
about Membase is how they are adding a persistence layer on top of Memcached
that gradually moves less used data down the stack to progressively slower and
more expansive storage hardware, starting from ram, going to ssds, then down
to hard drives.

One thing that they make a big deal about is ease of use in installing,
saying:

"Start storing data in five minutes, or less. Membase is a single-package
install. It is easy to get, install, configure and begin using. We consider it
a failure if it takes more than five minutes to get up and running."

While I appreciate ease of use and their dedication to that, if I'm looking
for something to handle 500,000+ requests per second, then getting it up and
running initially within 5 minutes is not something I concerned with.

But that's just a nit pick. I'm intrigued to hear more, and I like that they
are building this on top of Memcached while utilizing the existing client API.

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Maro
Problem is, how is this different than something else: the days when you can
claim to be fast, scalable, distributed etc. and get some traction are over.
These terms are so overused and overhyped that they have lost all meaning to
potential users. In the database world, "scalable" is the new "object-
oriented".

~~~
memoryfault
I've been working on a distributed scalable social web 2.0 AJAX HTML5 iPhone
database in the cloud...it's going to be awesome.

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_debug_
The front page says, "A distributed key-value database for modern web
applications".

The heading of this HN submission is "Yet Another Distributed Scalable
Key/Value? (answer: no way!)"

The schizophrenia continues on the home page. "Does the world really need
another NoSQL database?"

This deliberate confusion is beyond idiotic.

~~~
ingenthr
It's not deliberate confusion. There was a lot of work to just getting the
code out there, and we're now working on more and more docs.

Have a look at [http://blog.northscale.com/northscale-blog/2010/07/what-
exac...](http://blog.northscale.com/northscale-blog/2010/07/what-exactly-is-
membase.html) and <http://dustin.github.com/2010/06/29/memcached-
vbuckets.html> for good technical content.

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StavrosK
I am baffled by these new trends. I have seen websites that need scalability
cache all the DB queries in memcached, but the queries didn't have any large
degree of temporal locality. How is this supposed to do anything other than
move the database into memory? Shouldn't the DBMS already do that by itself?
The only benefit I can see is that the queries would be memoized instead of
having to be run again and again, but I'm not sure that would be such a great
advantage if the entire DB was loaded in memory.

Anyway, I'm just thinking aloud here, but it seems to me that in many cases
you really don't want a caching layer above the DB...

~~~
sketerpot
This one isn't just a cache; it's a database with a simple key-value data
model. It has very good clustering support. It can handle datasets too large
for memory. It's fast, allegedly easy to set up (I haven't tried it), and you
can communicate with it using existing memcached client libraries. I think it
sounds like an interesting option.

I also think that, in a few months, Redis will probably have the same nice
characteristics of Membase, but with a much nicer set of datatypes. Membase
does everything I described _right now_ , though, which is worth something.

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lecha
After quickly reading the info on the front page I didn't see a direct
comparison with other distributed key-value stores. Could anyone point to a
comparison? (sorry if I've missed it)

I _think_ membase is analogous to redis (HD-backed memcached), but unlike
redis it distributes the data across multiple physical nodes. AFAIK Redis
needs the DB to fit on a single disk.

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wanderr
No way? Explain?

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jamesmphillips
yes, please. What the heck did that mean?

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tghw
Documentation is pretty much nonexistent. It looks like it could be
interesting, but I can't even tell what sort of operations, data types, etc.
are supported.

~~~
sketerpot
To clients, it looks exactly like a memcached server.

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maw
It may indeed look exactly like a memcached server, but that's not enough. A
client that speaks the memcache protocol assuming that it's talking to a cache
can make assumptions and cut corners which a client talking to a persistent
store ought not, and users and implementors of clients that speak the protocol
need to be aware of these issues.

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Smihsmih88
I downloaded and it looks like I can put all my session data into it instead
of MySQL

~~~
fizz972
What kind of session data do you store in MySQL?

