Hi, Jon,

Thanks for your interest in FastBit.  Here is a web page with a little 
bit more information about -part.txt: 
<https://sdm.lbl.gov/fastbit/doc/dataLoading.html>

If you use FastBit software directly, each "column" of a "table" is 
stored in its own file in raw binary format (with no padding, no 
decoration).  Guess that is what you describe as 0 offset, dense 
columnar binary data.

It is possible to write a wrapper to allow FastBit indexing capability 
to work with data in different organizations.  I imagine that you will 
need to write this wrapper layer in order for FastBit to work with 
your data that packs multiple columns into a single file.  The 
In-memory API might be something helpful for you in this case.  Here 
is a pointer to the documentation generated by doxygen 
<https://sdm.lbl.gov/fastbit/doc/html/group__FastBitIAPI.html>.

Please feel free to let us know if you have more quesitons.

John


On 11/3/16 4:32 PM, Woodring, Jonathan Lee wrote:
> I was looking to see if there was more documentation on -part.txt for the 
> Ibis implementation.
>
> In particular, is it possible to use an binary data that is a appended arrays 
> of columnar data, by providing the offset per array? As a related question, 
> could you specify a struct offset if the data happen to be an array of 
> structs (this particular use case isn't, but other data might be).
>
> Or does FastBit fundamentally require that the data are written as 0 offset, 
> dense columnar binary data?
>
> If not, how easy/hard would it be to use the library to be able to generate 
> indices on that sort of data? Essentially, the use case will not/cannot 
> reformat/copy the data because it is too big. Though, it is essentially 
> columnar, but not separate files per column (columns are offsets into a 
> single file).
>
> Thanks,
> -Jon
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