[erlang-questions] MySQL cluster - MnesiaXXL(tm) :)

Pat e <>
Sat Oct 21 22:00:19 CEST 2006


On 10/21/06, Ulf Wiger <> wrote:
> Den 2006-10-21 16:32:34 skrev Pat e <>:
>
> > How much work would it be needed to tweak Mnesia for massive database
> > storing?
>
> I think more than tweaking is involved, as Jay pointed out.
> You may, for example, read the following document from a
> vendor that claims to manage database storage in the petabyte
> range:
>
> http://www.teradata.com/t/pdf.aspx?a=83673&b=84876
>
That's cool, but let the Wal-Mart use that :)

> (They may even have some patents that will get in the way
> of such tweaking...)
>
>
> > Will it be necessary to completley rewrite mnesia for
> > multi-terabyte disk-only tables?
>
> Quite possibly, but this seems like an unrealistic undertaking.
> OTOH, developing pieces that would bring erlang closer to
> supporting multi-gigabyte disk storage solutions might be
> of value.
>
> Then again, the larger the data volume, the higher the price
> of failure (most likely). There are products that can do this
> today. They are usually quite expensive, but then again, most
> people who juggle terabytes of data are prepared to pay a pretty
> large sum of money for solid products and support. It's a
> difficult problem, to say the least.
>
> I would assume that if anyone would develop such a beast in
> Erlang, they wouldn't put it up on SourceForge, but sell it
> for big bucks. ;)
>
That's for sure, although forking several MM's$US upfront without
knowing if the project will pay it off is a bit risky. :)

It's more cautious to take the SourceForge way, and from there
build forward - only there is a problem from transacting with
two or three database systems instead of one.
That is why i ask about TB sizes.... imagine in year one
having say 10 to 20 thousand subscribed users, and then
going to 5 to 10 million users, AND keeping the staff of
1 to 2 developers (we could take extra 200 employees,
fork some 10 to 15MM$US on several thousand servers
upfront ... THEN WHAT??? if it goes wrong... VC's will
want to hang us :(

>
> > Has anyone have any idea how to bypass 2GB limit for
> > disk only tables, and how to effecivlly operate ram caching?
>
>
> You may google on 'site:erlang.org dets limit' and find several posts on
> the list on this topic. Here are two:
>
> http://www.erlang.org/ml-archive/erlang-questions/200004/msg00077.html
>
> http://www.erlang.org/ml-archive/erlang-questions/200604/msg00264.html
>
> As Håkan Mattsson's post (first one above) points out, ram caching
> would only solve one problem. Remote table load remains to be
> solved as well.
>
>
> > I think we will need to develop some blueprint in next years of
> > how to develop such powerful upgrade for Mnesia.
> >
> > Ulf... again, can you help? :)
>
> Not much, I think. I prototyped a low-level interface,
> as part of the rdbms patches, that would allow for plugging in
> other table types in mnesia. I did toy with the idea of trying
> to use it for a caching disk-only table type, but haven't even
> started an implementation for it. I'm not completely convinced
> that the (external_copies) approach I took was the right one,
> and (more importantly), neither is Dan Gudmundsson, who
> maintains mnesia.
>
> And right now, I have lots of other things that get higher
> priority.
>
Tell us more :)

On 10/21/06, Pat e <> wrote:
> On 10/21/06, Ulf Wiger <> wrote:
> > Den 2006-10-21 16:32:34 skrev Pat e <>:
> >
> > > How much work would it be needed to tweak Mnesia for massive database
> > > storing?
> >
> > I think more than tweaking is involved, as Jay pointed out.
> > You may, for example, read the following document from a
> > vendor that claims to manage database storage in the petabyte
> > range:
> >
> > http://www.teradata.com/t/pdf.aspx?a=83673&b=84876
> >
> That's cool, but let the Wal-Mart use that :)
>
> > (They may even have some patents that will get in the way
> > of such tweaking...)
> >
> >
> > > Will it be necessary to completley rewrite mnesia for
> > > multi-terabyte disk-only tables?
> >
> > Quite possibly, but this seems like an unrealistic undertaking.
> > OTOH, developing pieces that would bring erlang closer to
> > supporting multi-gigabyte disk storage solutions might be
> > of value.
> >
> > Then again, the larger the data volume, the higher the price
> > of failure (most likely). There are products that can do this
> > today. They are usually quite expensive, but then again, most
> > people who juggle terabytes of data are prepared to pay a pretty
> > large sum of money for solid products and support. It's a
> > difficult problem, to say the least.
> >
> > I would assume that if anyone would develop such a beast in
> > Erlang, they wouldn't put it up on SourceForge, but sell it
> > for big bucks. ;)
> >
> That's for sure, although forking several MM's$US upfront without
> knowing if the project will pay it off is a bit risky. :)
>
> It's more cautious to take the SourceForge way, and from there
> build forward - only there is a problem from transacting with
> two or three database systems instead of one.
> That is why i ask about TB sizes.... imagine in year one
> having say 10 to 20 thousand subscribed users, and then
> going to 5 to 10 million users, AND keeping the staff of
> 1 to 2 developers (we could take extra 200 employees,
> fork some 10 to 15MM$US on several thousand servers
> upfront ... THEN WHAT??? if it goes wrong... VC's will
> want to hang us :(
>
> >
> > > Has anyone have any idea how to bypass 2GB limit for
> > > disk only tables, and how to effecivlly operate ram caching?
> >
> >
> > You may google on 'site:erlang.org dets limit' and find several posts on
> > the list on this topic. Here are two:
> >
> > http://www.erlang.org/ml-archive/erlang-questions/200004/msg00077.html
> >
> > http://www.erlang.org/ml-archive/erlang-questions/200604/msg00264.html
> >
> > As Håkan Mattsson's post (first one above) points out, ram caching
> > would only solve one problem. Remote table load remains to be
> > solved as well.
> >
> >
> > > I think we will need to develop some blueprint in next years of
> > > how to develop such powerful upgrade for Mnesia.
> > >
> > > Ulf... again, can you help? :)
> >
> > Not much, I think. I prototyped a low-level interface,
> > as part of the rdbms patches, that would allow for plugging in
> > other table types in mnesia. I did toy with the idea of trying
> > to use it for a caching disk-only table type, but haven't even
> > started an implementation for it. I'm not completely convinced
> > that the (external_copies) approach I took was the right one,
> > and (more importantly), neither is Dan Gudmundsson, who
> > maintains mnesia.
> >
> > And right now, I have lots of other things that get higher
> > priority.
> >
> Tell us more :)
>
> > BR,
> > Ulf W
> > --
> > Ulf Wiger
> >
>




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