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Posted to dev@activemq.apache.org by JustinSands <ju...@yahoo.com> on 2010/07/22 20:26:07 UTC

KahaDB PageFile binary page layout

I am trying to use KahaDB to write a large binary file which will be read by
a C++ process.  I'm mainly using Kaha for the transaction support. 
Everything looks really good so far!, however I have a few things I need to
make sure of:

1) Is the binary page file layout really just as simple as:
     Page: [ [ header (PAGE_HEADER_SIZE bytes) ] 
                [ ... unstructured (getPageContentSize() bytes)) ]
              ]
     ...

2) Are pages always allocated consecutively in 'Page Space'?


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Re: KahaDB PageFile binary page layout

Posted by Hiram Chirino <hi...@hiramchirino.com>.

On Thu, Jul 22, 2010 at 2:26 PM, JustinSands <ju...@yahoo.com> wrote:
>
> I am trying to use KahaDB to write a large binary file which will be read by
> a C++ process.  I'm mainly using Kaha for the transaction support.
> Everything looks really good so far!, however I have a few things I need to
> make sure of:
>
> 1) Is the binary page file layout really just as simple as:
>     Page: [ [ header (PAGE_HEADER_SIZE bytes) ]
>                [ ... unstructured (getPageContentSize() bytes)) ]
>              ]
>     ...

Sorta.. you got to also consider that page type is PAGE_PART_TYPE,
then the content size field actually points to the next page.

>
> 2) Are pages always allocated consecutively in 'Page Space'?
>

Yeah

BTW.. the next generation KahaDB is actually at http://hawtdb.fusesource.org/
So you might also want to take peek at that since it's independently
released from ActiveMQ.  It's has most of the same concepts except
that it also throws in MVCC transaction support.

>
> --
> View this message in context: http://old.nabble.com/KahaDB-PageFile-binary-page-layout-tp29239196p29239196.html
> Sent from the ActiveMQ - Dev mailing list archive at Nabble.com.
>
>

-- 
Regards,
Hiram

Blog: http://hiramchirino.com

Open Source SOA
http://fusesource.com/